Laparoscopic versus conventional Nissen fundoplication: the influence on plasma insulin-like growth factor-I and insulin-like growth factor binding protein-3

BACKGROUND

Conventional surgery is known to influence postoperative insulin-like growth factor-I (IGF-I) levels and to increase protein breakdown. Recent animal data described that laparoscopic surgery, in contrast to conventional surgery, maintains postoperative IGF-I levels, suggesting a reduced postoperative catabolic response.

AIM

The aim of this study was to demonstrate differences in the postoperative catabolic response between laparoscopic and conventional surgery.

METHODS

Seventeen patients scheduled for Nissen fundoplication were randomly assigned to undergo either a laparoscopic or a conventional procedure. The catabolic response was assessed by measuring total IGF-I and insulin-like growth factor binding protein-3 (IGFBP-3).

RESULTS

IGF-I levels decreased significantly 4 days after both types of surgery. IGFBP-3 decreased more rapidly after conventional surgery than after the laparoscopic technique; however, the differences between the groups were not significant.

CONCLUSION

In contrast to animal data, no differences in plasma IGF-I or IGFBP-3 were seen in patients undergoing laparoscopic or conventional Nissen fundoplication.

Flavonoids: a review of probable mechanisms of action and potential applications

The aim of this review, a summary of the putative biological actions of flavonoids, was to obtain a further understanding of the reported beneficial health effects of these substances. Flavonoids occur naturally in fruit, vegetables, and beverages such as tea and wine. Research in the field of flavonoids has increased since the discovery of the French paradox,ie, the low cardiovascular mortality rate observed in Mediterranean populations in association with red wine consumption and a high saturated fat intake. Several other potential beneficial properties of flavonoids have since been ascertained. We review the different groups of known flavonoids, the probable mechanisms by which they act, and the potential clinical applications of these fascinating natural substances.

Glutamine alimentation in catabolic state

Glutamine should be reclassified as a conditionally essential amino acid in the catabolic state because the body's glutamine expenditures exceed synthesis and low glutamine levels in plasma are associated with poor clinical outcome. After severe stress, several amino acids are mobilized from muscle tissue to supply energy and substrate to the host. Glutamine is one of the most important amino acids that provide this function. Glutamine acts as the preferred respiratory fuel for lymphocytes, hepatocytes and intestinal mucosal cells and is metabolized in the gut to citrulline, ammonium and other amino acids. Low concentrations of glutamine in plasma reflect reduced stores in muscle and this reduced availability of glutamine in the catabolic state seems to correlate with increased morbidity and mortality. Adding glutamine to the nutrition of clinical patients, enterally or parenterally, may reduce morbidity. Several excellent clinical trials have been performed to prove efficacy and feasibility of the use of glutamine supplementation in parenteral and enteral nutrition. The increased intake of glutamine has resulted in lower septic morbidity in certain critically ill patient populations. This review will focus on the efficacy and the importance of glutamine supplementation in diverse catabolic states.

Low arginine plasma levels do not aggravate renal blood flow after experimental renal ischaemia/reperfusion

BACKGROUND

Ischaemic renal dysfunction is present in many clinical settings, including cardiovascular surgery. Renal hypoperfusion seems to be the most important pathophysiologic mechanism. Arginine plasma levels are rate limiting for NO synthesis, and low arginine plasma levels are seen after major vascular surgery.

OBJECTIVE

to establish the effects of low arginine plasma levels on renal blood flow after renal ischaemia/reperfusion.

DESIGN

Wistar rats were used in this unilateral renal ischaemia/reperfusion model. After 70 min of ischaemia, the kidney was reperfused for 150 min. Arginase infusion was used to lower arginine plasma levels. Blood flow measurement was performed at the end of the experiment using radiolabelled microspheres. Additional experiments were performed for histopathology.

RESULTS

Arginase efficiently decreased arginine plasma levels to about 50% of normal. There was a lower blood flow in the ischaemic kidney than the contralateral (non-ischaemic) kidney. Lowering arginine plasma levels did not reduce renal blood flow in the ischaemic kidney. Renal histopathology was not influenced by lowered arginine plasma levels.

CONCLUSIONS

Lowering arginine plasma levels did not affect blood flow or histology following renal ischaemia and reperfusion.

Arginase release from red blood cells: possible link in transfusion induced immune suppression?

Arginine stimulates lymphocyte function and is degraded by arginase, an enzyme that is abundantly present in red blood cells. Arginase impairs lymphocyte function and responses in vitro. Leakage of arginase from stored red blood cells may be involved in the lymphocyte dysfunction associated in allogenic blood transfusion. In the present study, arginase activity was determined in bags of red cells stored for transfusion. Buffy coat depleted red blood cells were obtained routinely from four healthy donors and stored in bags for a maximum period of five weeks at 4 degrees C. The bags were sampled for determination of arginase, lactate dehydrogenase, and potassium. In addition, a random sample of 36 bags of red blood cells about to be transfused to patients were studied. Levels of arginase, lactate dehydrogenase, and potassium showed a time dependent increase in the bags of the four donors. This time dependent increase in arginase activity could be confirmed in the additional bags sampled (P < 0.0001, r = 0.78). The results for the first time show that arginase is released from red blood cells during storage for transfusion. Arginase infusion may play an important role in the immune suppression observed after blood transfusion.

The sentinel lymph node status is an important factor for predicting clinical outcome in patients with Stage I or II cutaneous melanoma

BACKGROUND

In a cohort of patients, the authors investigated whether and to what extent the sentinel lymph node (SLN) status contributes to predicting the probability of remaining disease free for at least 3 years. In addition, several traditional prognostic factors were analyzed: Breslow thickness, Clark invasion level, ulceration, lymphatic invasion, location, type of the melanoma, and age and gender of the patient.

METHODS

In 263 consecutive patients with proven American Joint Committee on Cancer Stages I and II cutaneous melanoma, the triple technique SLN procedure was used, i.e., preoperative visualization of the lymph channels from the initial site of the melanoma toward the SLN by (dynamic) lymphoscintigraphy, intraoperative visualization of those particular lymph channels and lymph nodes with blue dye, and a gamma probe to measure accumulated radioactivity in radiolabeled lymph nodes. Median follow-up time was 48 months (range, 36-84 months). Multivariate logistic regression analysis was performed to examine the influence of the SLN status and several other prognostic factors on a minimum 3-year disease free survival.

RESULTS

In 20% of patients, the SLN proved to be tumor positive. For SLN negative patients, the 5-year disease free survival rate was 91% (+/- 2.4%), and for SLN positive patients it was 49% (+/- 9%). Five variables showed a strong and statistically significant independent prognostic association with outcome, i.e., SLN status (P = 0.0007), thickness of primary melanoma (1.01-2.0 mm; P = 0.04), ulceration (P = 0.05), and lymphatic invasion (P = 0.01) of primary melanoma, and age (40-50 years; P = 0.01).

CONCLUSIONS

The SLN status-along with Breslow thickness, ulceration, lymphatic invasion, and age--seems to have strong additional value in predicting a minimum 3-year disease free period after the SLN procedure. Patients with a positive SLN have a poorer prognosis than those with a negative SLN.

No indication for performing sentinel node biopsy in melanoma patients with a Breslow thickness of less than 0.9 mm

In thin melanomas, the involvement of regional nodes is very uncommon. Recent sentinel node (SN) studies have confirmed the absence of positive regional lymph nodes in melanomas < 0.76 mm and a 5% positivity in melanomas between 1.0 and 1.99 mm. The chance of regional lymph node involvement - and therefore whether it is relevant to perform the SN procedure - seems to depend on the Breslow thickness of the primary tumour. However, a Breslow thickness cut-off point has not yet been established. We evaluated a melanoma population that had undergone an SN procedure to determine this point, so that the procedure can be restricted to a smaller group of patients in future. In a total of 348 patients with proven American Joint Committee on Cancer (AJCC) stages I or II cutaneous melanoma with a Breslow thickness > or = 0.5 mm the triple technique was used, consisting of preoperative visualization of the lymph channels from the initial site of the melanoma towards the SN by (dynamic) lymphoscintigraphy, intraoperative visualization of those particular lymph channels and nodes with blue dye, and a gamma probe to measure accumulated radioactivity in radiolabelled lymph nodes. In melanomas thinner than 0.90 mm, no positive SN was found (95% confidence interval 0-5%). This group consisted of 75 patients (22%), with a median follow-up of 31 months. Our data suggest that this procedure need no longer be indicated for almost a quarter of the patient population, because the cut-off point for nodal involvement appears to be a Breslow thickness of 0.90 mm.

Metastatic pattern of CC531 colon carcinoma cells in the abdominal cavity: an experimental model of peritoneal carcinomatosis in rats

BACKGROUND

Peritoneal spread of tumour cells is a major source of morbidity and mortality in patients with colorectal cancer. In order to develop strategies to prevent intraperitoneal dissemination and to treat peritoneal carcinomatosis, the spread of tumour cells in the peritoneal cavity was studied.

METHODS

Two million CC531 colon carcinoma cells were administered intraperitoneally in five groups of eight rats. The rats were killed after 1, 2, 4 and 8 hours and 3, 7, 14 and 21 days. After inspection of the abdominal cavity, samples of blood and ascites were taken. Liver, spleen, omentum, mesentery, diaphragm, parathymic lymph nodes and lungs were removed for histology and immunohistochemistry.

RESULTS

No abnormalities were seen in the abdominal cavity until day 3. Subsequently the peritoneum and omentum became thickened and after 21 days all rats had haemorrhagic ascites and peritoneal carcinomatosis. The abdominal fluid contained tumour cells at all stages. The number of tumour cells decreased in the first 8 hours, and increased thereafter. At microscopy the peritoneum was completely covered by tumour cells after 3 days. Tumour cells concentrated in the milky spots (MS) of the omentum within 4 hours. The size of the MS increased as a result of an increase in number of tumour cells and macrophages. After 7--21 days the MS were completely replaced by tumour cells and new MS were formed. In the diaphragm tumour cells invaded the lymphatic lacunae after 8 h, and obliterated these after 3--7 days. Also invasion of the muscle fibres was seen after 3 days. Microscopically no tumour cells were found in blood, liver, spleen, parathymic nodes and lung.

CONCLUSION

After intraperitoneal administration of CC531 colon carcinoma cells, tumour cells spread throughout the abdominal cavity, and concentrate in the milky spots of the greater omentum, the paracolic gutters, the subhepatic and subphrenic spaces and in the lymphatic lacunae of the diaphragm.

Perioperative treatment with bactericidal/permeability-increasing protein (rBPI21) in major liver surgery: a concise summary

INTRODUCTION

Major hepatic resections are still associated with considerable morbidity. Gut-derived bacteria and bacterial endotoxin are considered to play a central role in the pathophysiology of complications. Experimental studies suggest that bactericidal/permeability-increasing protein (BPI), which has both antibacterial and endotoxin-neutralising properties, can reduce postoperative complications.

MATERIAL AND METHODS

A phase II, double-blind, placebo-controlled, multicentre, dose escalation trial was conducted in patients undergoing major liver resection, and clinical outcome, infectious complications, plasma amino acid patterns, coagulation and fibrinolytic cascade systems and neutrophil functions were compared between the two treatment groups and an extra group of patients undergoing major abdominal non-hepatic surgery.

RESULTS

Drug administration in this patient group was safe, and resulted in a significant reduction of infectious complications. Furthermore, beneficial effects were found in the postoperative amino acid ratio and fibrinolytic cascades, and rBPI21 preserved leukocyte functions.

CONCLUSION

Administration of rBPI21 in patients undergoing major liver resection is well tolerated and results in improvement of both clinical and biochemical parameters.

Immune-stimulating effects of low-dose perioperative recombinant granulocyte-macrophage colony-stimulating factor in patients operated on for primary colorectal carcinoma

BACKGROUND

Surgery induces a postoperative immunosuppression, thereby possibly facilitating the outgrowth of pre-existing occult metastases or the seeding of disseminated tumour cells in patients with primary colorectal carcinoma operated on with curative intent. The hypothesis that adjuvant therapy with perioperative recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) would minimize postoperative immunosuppression was investigated in this pilot study.

METHODS

Patients were allocated randomly to receive daily subcutaneous injections with either saline (n = 8) or rhGM-CSF 2.8 microg per kg body-weight (n = 8) from 3 days before operation until 4 days afterwards. Phytohaemagglutinin (PHA) skin test reactivity, monocyte human leucocyte antigen (HLA) DR expression and the extent of the acute-phase response, by determination of white blood cell count and differentiation, plasma interleukin (IL) 6 levels and body temperature in the perioperative period, were examined.

RESULTS

rhGM-CSF treatment minimized postoperative suppression in PHA skin test reactivity and increased the numbers of neutrophils and monocytes while enhancing the expression of HLA-DR in the postoperative period. Additionally, both postoperative plasma IL-6 levels and the incidence of fever tended to be higher in the rhGM-CSF group.

CONCLUSION

In this pilot study, perioperative administration of low-dose rhGM-CSF stimulated certain immune functions that are normally depressed after operation. The implications for the antitumour responses directly after operation and the formation of liver metastases are currently under investigation.

Coagulopathy following major liver resection: the effect of rBPI21 and the role of decreased synthesis of regulating proteins by the liver

This prospective study investigated the role of reduced hepatic synthesis of regulating proteins in coagulopathy after partial hepatectomy (PH) compared with major abdominal surgery (MAS) without involvement of the liver. Furthermore, we studied the effect of rBPI21, an endotoxin-neutralizing agent, on coagulopathy after PH was studied. Compared with MAS, PH resulted in significantly elevated levels of thrombin-antithrombin-III and plasmin-alpha2-antiplasmin complexes. Levels of antithrombin-3, alpha2-antiplasmin, fibrinogen, plasminogen, alpha2-macroglobulin (alpha2-M), and C1-inhibitor remained lower following PH. Treatment with rBPI21 led to significantly lower levels of tissue-type plasminogen activator (t-PA). Post-operative disseminated intravascular coagulation (DIC) was associated with significantly higher bilirubin and t-PA plasma levels and significantly lower levels of alpha2-M. This study indicates that PH induced hepatic failure results in decreased synthesis of hepatic regulating plasma proteins and subsequent activation of coagulation and fibrinolysis. Prevention of t-PA release by rBPI21 may have important clinical implications. Decreased availability of alpha2-M may be a factor in post-operative DIC.

Effect of perioperative nutrition, with and without arginine supplementation, on nutritional status, immune function, postoperative morbidity, and survival in severely malnourished head and neck cancer patients

BACKGROUND

Malnourished head and neck cancer patients are at increased risk of postoperative complications.

OBJECTIVE

We studied the effect of perioperative, arginine-supplemented nutritional support on nutritional status, immune status, postoperative outcome, and survival in severely malnourished (weight loss >10% of body weight) head and neck cancer patients undergoing major surgery.

DESIGN

Forty-nine patients were randomly assigned to receive 1) no preoperative and standard postoperative tube feeding, 2) standard preoperative and postoperative tube feeding, or 3) arginine-supplemented preoperative and postoperative tube feeding.

RESULTS

Patients in both prefed groups received approximately 9 d of preoperative tube feeding, resulting in energy intakes of 110% and 113% of calculated needs (compared with 79% in the control group; P = 0.007). Compared with no preoperative feeding, preoperative enteral nutrition did not significantly improve nutritional status or any of the studied biochemical or immunologic indexes. Major postoperative complications occurred in 53%, 47%, and 59% of patients in study groups 1, 2, and 3 (NS). A trend was seen toward better survival in the arginine-supplemented group (P = 0.15). Secondary analysis showed that survivors had better human leukocyte antigen-DR expression on monocytes (P = 0.05) and higher endotoxin-induced cytokine production (P = 0.010 for tumor necrosis factor alpha and P = 0.042 for interleukin 6) at the start of the study than did patients who died.

CONCLUSIONS

Nine days of preoperative tube feeding, with or without arginine, did not significantly improve nutritional status, reduce the surgery-induced immune suppression, or affect clinical outcome in severely malnourished head and neck cancer patients. Patients supplemented with arginine-enriched nutrition tended to live longer. Some markers of immune function may distinguish patients with good or bad prognoses.

Major liver resection results in a changed plasma amino acid pattern as reflected by a decreased Fischer ratio which improves by bactericidal/permeability increasing protein

BACKGROUND/AIMS

Major liver resection results in a high morbidity and mortality, and endotoxin plays a role in post-resection hepatic failure. Severe hepatic failure as seen in hepatitis and cirrhosis may be accompanied by hepatic encephalopathy and is characterized by a typical plasma amino acid pattern reflected by a decreased Fischer ratio. This study was performed to evaluate the plasma amino acid pattern in patients undergoing major liver surgery receiving placebo or the endotoxin-neutralizing agent bactericidal/permeability-increasing protein (rBPI21).

PATIENTS AND METHODS

Forty-eight patients were randomized in this phase II, dose escalation, multicenter trial. Plasma amino acid profiles were determined preoperatively, and on the first (day 1) and third (day 3) postoperative day.

RESULTS

In the placebo group the Fischer ratio decreased significantly on both postoperative days. Administration of rBPI21 also resulted in a decreased Fischer ratio on day 1, but not on day 3. Highly elevated alanine plasma levels were observed on day 1 in placebo-treated patients, whereas rBPI21 prevented this elevation. Plasma alanine levels on day 1 correlated with the duration of post-resection hepatic failure.

CONCLUSIONS

Major liver resection results in a decreased Fischer ratio and a rise in plasma alanine levels. Plasma levels of alanine on the first postoperative day correlated with the duration of the post-resection hepatic failure. rBPI21 improved the Fischer ratio and prevented the rise of plasma alanine levels.

Survival of malnourished head and neck cancer patients can be predicted by human leukocyte antigen-DR expression and interleukin-6/tumor necrosis factor-alpha response of the monocyte

BACKGROUND

Patients with advanced stages of head and neck cancer are often characterized by malnutrition and by an impaired immune system. Because some of the suppressed immune parameters were shown to be of prognostic importance in trauma and sepsis, we investigated whether these would also correlate with survival in head and neck cancer.

METHODS

Severely malnourished head and neck cancer patients undergoing ablative and reconstructive surgery were followed prospectively and their perioperative immune parameters were related to long-term survival.

RESULTS

Forty-nine patients with a preoperative weight loss of more than 10% were followed up for a period of at least 16 months after surgery. Analyses of variance revealed that preoperative human leukocyte antigen-DR (HLA-DR) expression on monocytes and endotoxin-induced production of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) were different between patients who survived and patients who died. Proportional hazards identified a weight loss of more than 12%, the presence of coexistent disease, and an HLA-DR expression on monocytes below the cutoff points (mean fluorescence index < 15, peak channel index < 9) to be of significant influence on survival.

CONCLUSIONS

In addition to known prognostic parameters such as tumor stage, coexistent disease, and weight loss, the immune parameters HLA-DR expression on monocytes and endotoxin-induced cytokine production may carry prognostic value in cancer patients. Immunomodulating therapies leading to improvement of these parameters might in the future lead to increased options for treatment.

The influence of laparoscopic surgery on postoperative polymorphonuclear leukocyte function

BACKGROUND

Laparoscopic surgery is thought to result in a better preservation of patients' immunological defenses. Polymorphonuclear leukocytes (PMN) are the most important effector cells in the elimination of pathogenic microorganisms. Because little is known about their function after laparoscopic surgery, we studied PMN phagocytosis, antigen expression, and oxygen radical production.

METHODS

In this study, 17 patients scheduled for Nissen fundoplication were randomly assigned to undergo either a laparoscopic or conventional procedure. To study phagocytic capacity, PMN were incubated with fluorescein isothiocyanate (FITC)-labeled Staphylococcus aureus. Plasma opsonic capacity was measured by comparing PMN phagocytosis in the presence of patients' own plasma with phagocytosis in the presence of control plasma. Cellular activation was measured by the expression of various cell surface markers and by assessment of PMA-stimulated oxidative burst.

RESULTS

Phagocytosis by PMN in the presence of patients' plasma was significantly lower 2 h after the conventional operation. No decrease in phagocytosis was observed when control plasma was used, indicating a decreased opsonic capacity of plasma after conventional surgery. No changes were observed after laparoscopic surgery. Furthermore, CD11b expression was significantly lower after the laparoscopic approach, indicating a blunted cellular activation. A significantly lower PMA-stimulated oxidative burst further confirmed the tempered stimulation after laparoscopic surgery.

CONCLUSIONS

Laparoscopic surgery results in a preservation of the plasma opsonic capacity, and thereby the ability of PMN to phagocytose bacteria. Moreover, the postoperative cellular activation is reduced. The preserved phagocytosis and the blunted activation may prevent the development of postoperative infectious complications.

Interleukin-10 appearance following thoraco-abdominal and abdominal aortic aneurysm repair is associated with the duration of visceral ischaemia

OBJECTIVES

to evaluate the plasma IL-10 levels during elective operative repair of thoraco-abdominal and abdominal aortic aneurysm repair. To study whether IL-10 plasma levels are associated with the duration of cross-clamping (ischaemia) and clinical outcome.

MATERIALS

fifteen consecutive patients undergoing surgery for TAAA and 10 consecutive patients undergoing surgical repair of AAA were included.

METHODS

plasma concentrations of IL-10 were measured by ELISA technique. Clinical outcome of the TAAA patients was prospectively analysed.

RESULTS

during aortic clamping IL-10 was produced in both populations. The plasma IL-10 peak (934+/-172 pg/ml) of the TAAA group was seen at 4 h after declamping and remained detectable after 48 h. The plasma IL-10 peak (212+/-32 pg/ml) of the AAA group was seen 30 min after declamping and fell to undetectable levels by 24 h. These data show that the peak IL-10 plasma levels in TAAA repair are significantly (p<0.05) higher compared to the peak IL-10 plasma levels as seen during AAA repair. A positive correlation was seen between cross-clamping and peak plasma IL-10 and organ dysfunction.

CONCLUSIONS

IL-10 plasma concentrations appear higher, later and are longer detectable in patients undergoing TAAA. Correlations were seen with duration of cross-clamping and MSOD.

Bactericidal/permeability-increasing protein preserves leukocyte functions after major liver resection

OBJECTIVE

To analyze postoperative leukocyte functions in patients undergoing hemihepatectomy, and to assess the effect of treatment with the endotoxin-neutralizing agent bactericidal/permeability-increasing protein (rBPI21).

SUMMARY BACKGROUND DATA

Extensive liver resection is associated with a high incidence of infectious complications. Because elimination of pathogenic microorganisms occurs mainly by leukocytes, this increased rate of infections is most likely due to an impaired function of these cells. Endotoxin, translocated from the gut into the systemic circulation as a result of increased gut permeability and reduced hepatic clearance function after major liver resection, may play an important role in the impairment of posthepatectomy leukocyte function.

METHODS

To investigate whether hemihepatectomy results in impaired leukocyte functions and to determine the role of endotoxin in this process, leukocyte oxidative burst and leukocyte antigen expression were studied in three groups of patients: patients undergoing a hemihepatectomy and receiving rBPI21 treatment, patients undergoing hemihepatectomy and receiving placebo, and as an extra control group patients undergoing other major abdominal surgeries. Blood samples were collected before surgery, 2 hours after surgery, and at days 1, 2, 5, and 7. Phorbol myristate acetate-stimulated oxidative burst was measured using dihydrorhodamine, and leukocyte surface expression of the antigens CD11b, CD16, and CD14 was investigated by indirect immunofluorescence. Both oxidative burst and membrane surface expression were quantified by flow cytometry. An indication of the antiendotoxin effect of rBPI21 treatment was provided by assessment of plasma lipopolysaccharide binding protein (LBP) levels by enzyme-linked immunosorbent assay.

RESULTS

The oxidative burst in the hemihepatectomized patients receiving placebo and the controls increased 2 hours after surgery, whereas it decreased in the rBPI21-treated patients, resulting in significant differences between the groups. On day 1, neutrophil CD11b expression and monocyte CD14 expression in the rBPI21-treated patients and controls were significantly lower than in the placebo group. At 2 hours, CD16 expression in the placebo-treated patients was significantly higher than in the rBPI21-treated patients and controls. On day 5 and day 7, plasma LBP levels were significantly higher in the placebo-treated patients compared with the rBPI21-treated patients.

CONCLUSIONS

The results of this study show that patients undergoing major liver resection have an increased activation of leukocytes compared with those undergoing other major abdominal surgery. This enhanced activation may contribute to the increased risk of infection in these patients. Administration of the endotoxin-neutralizing agent rBPI21 to hemihepatectomy patients was shown to reduce plasma LBP levels, to preserve leukocyte functions partially, and to reduce leukocyte activation to the level of other, nonhepatic abdominal surgery.

Low arginine plasma levels in patients after thoracoabdominal aortic surgery

OBJECTIVE

Thoracoabdominal aortic surgery is a high-risk procedure and associated with a significant morbidity and mortality. Ischemia reperfusion of visceral organs and lower extremities is one of the most important determinants of this morbidity. Arginine is the precursor of nitric oxide and arginine plasma levels are important in maintaining organ blood flow. Furthermore, arginine is important in wound healing and the immune system. Because of increased utilization of arginine, low arginine plasma levels could be expected after thoracoabdominal aortic surgery. We therefore measured arginine plasma levels in these patients.

DESIGN

Six patients with thoracoabdominal aortic aneurysm were included in this study.

SETTING

University Hospital Vrije Universiteit, Department of Surgery, Amsterdam, The Netherlands.

SUBJECTS

Six patients undergoing thoracoabdominal aortic surgery.

INTERVENTION

Plasma levels of arginine were measured by high-performance liquid chromatography.

RESULTS

Very low arginine plasma levels were seen on the first postoperative day. From day 1 arginine slowly increased, but did not reach normal plasma levels on day 6.

CONCLUSIONS

A significant decrease of arginine plasma levels was found and because of the fact that arginine has multiple functions, it may be important to keep these arginine plasma levels at normal or even higher levels in patients undergoing major vascular surgery. European Journal of Clinical Nutrition (2000) 54, 615-617.

Reliability of the sentinel node procedure in melanoma patients: analysis of failures after long-term follow-up

BACKGROUND

The sentinel node (SN) concept assumes that early lymphatic metastases, if present, always are found first in the SN. The aim of this study was to determine the reliability of this procedure by establishing the success rate and number of failed procedures during a follow-up period of at least 2 years.

METHODS

From August 1993 to November 1996, 204 consecutive patients with stage I and II cutaneous melanoma underwent SN biopsy by a triple technique. Preoperatively, all patients underwent (dynamic) lymphoscintigraphy. A gamma probe and blue dye helped localize the SN(s) during surgery, and these nodes subsequently were excised. These lymph nodes were step-sectioned and examined by routine and immunohistochemical staining. If the SN contained tumor cells, a lymphadenectomy was performed at a later date.

RESULTS

The median follow-up time was 42 months. The success rate was 99%. Three patients developed a recurrence in the negative SN basin during follow-up, without simultaneous appearance of (locoregional) metastases.

CONCLUSIONS

With a 99% success rate and a 1.5% rate of failed SN procedures (7% false-negative rate) after a median follow-up of 3.5 years, we concluded that the combined triple technique approach of detecting the SN was a reliable method to accurately identify and retrieve the SN.

The effect of mild endotoxemia during low arginine plasma levels on organ blood flow in rats

OBJECTIVE

Arginine is the sole precursor in the generation of the vasodilating agent nitric oxide. Arginine plasma levels are low in situations associated with endotoxemia such as major trauma, sepsis, and experimental obstructive jaundice. The aim of the study was to evaluate hemodynamics at low arginine plasma levels during a low-grade endotoxemia.

DESIGN

Randomized, placebo-controlled animal laboratory investigation.

SUBJECTS

Male Wistar rats (n = 29), anesthetized.

INTERVENTIONS

Rats were randomly assigned to receive (at t = 0 mins) an intravenous infusion of 1.5 mL of 0.9% NaCl (SAL, n = 12) or 1.5 mL of an arginase (3200 IU) solution (ASE, n = 17) over a 20-min period. After the SAL or ASE infusion, rats were randomly assigned to receive an intravenous endotoxin (lipopolysaccharide [LPS], 150 microg/kg in 1.0 mL of 0.9% NaCl; ASE/LPS, n = 10 and SAL/LPS, n = 6) challenge or a control infusion (1.0 mL of 0.9% NaCl; ASE/SAL, n = 7 and SAL/SAL, n = 6) at t = 30 mins.

MEASUREMENTS AND MAIN RESULTS

Organ blood flow was measured at t = 270 mins, using radiolabeled microspheres. At this time point, arginine plasma levels were lower in the ASE-treated rats (ASE/SAL vs. SAL/SAL and ASE/LPS vs. SAL/LPS, both p < .005, respectively). Cardiac output, mean arterial pressure, and therefore total peripheral resistance were similar for all groups. In the LPS-treated animals (SAL/LPS and ASE/LPS), cardiac output was maintained by a higher heart rate compensating the lower stroke volume. Organ blood flow to the small intestine and splanchnic blood flow was lower in the ASE/LPS-treated rats (both p < .05 when compared with other groups). Total liver blood flow was similar for all groups; the lower splanchnic blood flow was compensated for by a higher hepatic arterial blood flow.

CONCLUSION

The present study shows that low arginine plasma levels do not influence organ blood flow, whereas, during a low-grade endotoxemia, low arginine plasma levels result in reduced blood flow to the small intestine.

Laparoscopic surgery preserves monocyte-mediated tumor cell killing in contrast to the conventional approach

BACKGROUND

Experimental animal research shows that immunologic defenses against tumor cells are disturbed by surgical trauma, resulting in an increased rate of tumor implantation and the growth of subsequent metastases. Minimally invasive surgery is associated with a preservation of postoperative immunologic functions and, in animal models, with decreased tumor growth. The objective was to study the influence of several surgical procedures, approached conventionally and laparoscopically, on interleukin-6 (IL-6) and monocyte-mediated cytotoxicity (MMC).

METHODS

Five groups of five patients each were included in this prospective study: laparoscopic cholecystectomy (minor trauma) group, Nissen fundoplication (laparoscopic and conventional as moderate trauma) groups, and sigmoid colectomy (laparoscopic and conventional as major trauma) groups. Preoperatively, 1 and 4 days after surgery, IL-6 and MMC against SW948 colon cancer cell line were determined.

RESULTS

The IL-6 levels differed significantly between the three laparoscopic procedures (p = 0.004) and increased according to the degree of trauma. There was no significant difference in MMC between the three laparoscopic procedures. However, MMC was suppressed after conventional procedures and preserved after laparoscopic procedures (p = 0.001). There was no correlation between IL-6 levels and changes in MMC.

CONCLUSIONS

More extensive laparoscopic procedures induce increased levels of IL-6, reflecting higher levels of trauma. Conventional surgical procedures result in depressed MMC in the postoperative period. After laparoscopic procedures, MMC is preserved. These findings may be of importance in preventing implantation and growth of cancer cells spread by surgical manipulation.

High plasma levels of arginine and liver arginase in Kupffer-cell-depleted rats after partial hepatectomy

BACKGROUND/AIMS

The remnant liver after partial hepatectomy releases arginase into the plasma, which is a reliable indicator of hepatocellular damage. Little information is available on how this release affects arginine plasma levels. We hypothesized that Kupffer cells after partial hepatectomy may prevent further hepatocellular damage, contributing to lower arginase release. The aim of the study was to evaluate the role of Kupffer cells in plasma arginase activity and arginine plasma levels after partial hepatectomy.

METHODS

Wag/Rij rats (n=72, 250-275 g) were randomly assigned to receive 1 ml liposome-encapsulated dichloromethylene-diphosphonate in order to eliminate Kupffer cells (DMDP, n=24), 1 ml liposome encapsulated-phosphate buffered saline (PBS, n=24) or 1 ml NaCl 0.9% (NaCl, n=24) intravenously. Forty-eight hours later, all rats had a two-third liver resection. Rats were killed at 0, 24, 48 and 96 h after partial hepatectomy.

RESULTS

Arginase plasma activity was higher in the DMDP-treated group compared to NaCl and PBS (both p<0.01, p<0.05, p<0.01 and p<0.05 for 0, 24, 48 and 96 h after partial hepatectomy respectively). Arginine plasma levels increased, but were lower in the DMDP group compared to NaCl and PBS (both p<0.05, 24 h after hepatectomy).

CONCLUSION

The study showed that Kupffer cell depletion results in a higher arginase release from the remnant liver after partial hepatectomy, indicating a hepatocellular protective function of Kupffer cells. Despite this arginase release, arginine plasma levels were increased after partial hepatectomy.

Kupffer cell depletion by CI2MDP-liposomes alters hepatic cytokine expression and delays liver regeneration after partial hepatectomy

BACKGROUND

Although Kupffer cells (KCs) are capable of producing important growth-stimulating cytokines, their role in liver regeneration following partial hepatectomy (PH) remains poorly understood.

METHODS

In the present study liver regeneration was studied after KC-depletion by intravenous administration of liposome-encapsulated dichloromethylene-diphosphonate (C12MDP), a method known to physically eliminate KCs. Furthermore, splenectomy was performed one week prior to PH to exclude the effect of C12MDP-liposomes on macrophage populations in the spleen.

RESULTS

KC-depletion was confirmed in cryostat liver sections stained with the monoclonal antibody ED2, a marker for resident tissue macrophages. Forty-eight hours after PH, the cumulative hepatocyte DNA synthesis, as determined in liver sections by the hepatocyte bromodeoxyuridine labeling index, was significantly decreased in KC-depleted rats when compared to control-rats. The weight of the remnant liver, expressed as a percentage of the initial liver weight, was significantly less at 96 h after PH in KC-depleted rats. KC-depletion abolished the hepatic interleukin-6 (IL-6) and interleukin-10 (IL-10) mRNA synthesis and decreased hepatic expression of tumor necrosis factor-alpha (TNF-alpha), hepatocyte growth factor (HGF) and transforming growth factor-beta1(TGF-beta1) mRNA after PH, as was assessed by reverse-transcriptase polymerase chain reaction (RT-PCR). Moreover, at 4 h after PH the systemic release of IL-6 was significantly decreased in KC-depleted rats.

CONCLUSION

We conclude that KCs are important for hepatocyte regeneration after PH. Delayed liver regeneration in KC-depleted rats can be explained, at least in part, by an imbalanced hepatic cytokine expression, thereby suppressing important growth-stimulating cytokines.

Organ blood flow after partial hepatectomy in rats: modification by endotoxin-neutralizing bactericidal/permeability-increasing protein (rBPI23)

BACKGROUND/AIM

Both maintenance of adequate perfusion and regeneration of the remnant liver are important in the recovery of liver function after partial hepatectomy. In previous experiments, we have shown that profound hypotension and liver injury can be attenuated by neutralizing endotoxins. The relative contribution of endotoxemia to changes in liver blood flow and blood flow to other major organs after partial hepatectomy is not known. The aim of this study was to examine the effect of endotoxin neutralization on individual organ blood flows including hepatic artery and splanchnic blood flow after experimental partial hepatectomy and its relation to liver cell proliferation.

METHODS

Male Wistar rats underwent either two-thirds partial hepatectomy or sham operation. Treatment consisted of continuous infusion of recombinant N-terminal bactericidal/permeability-increasing protein (rBPI23) or control protein. At 4 h after surgery, organ blood flows were measured using the radiolabeled microsphere technique, and at 24 h, proliferation index in liver tissue was calculated.

RESULTS

After partial hepatectomy, blood flows to virtually all organs were significantly lower as compared to values obtained in sham-operated rats. rBPI23 greatly improved hepatic artery flow (p<0.001) but not portal venous flow. These effects of rBPI23 on liver flow preceded an equally enhanced liver cell proliferation (p<0.01). Endotoxin neutralization led to significantly higher flows to some but not all splanchnic organs. Lung perfusion was significantly improved by rBPI23.

CONCLUSIONS

Neutralization of endogenous endotoxins improves liver blood flow after partial hepatectomy and also periportal and pericentral liver cell proliferation. This proliferation effect may result from an increased hepatic artery flow. Lung, colon, spleen and pancreas flow but not kidney flow was greatly enhanced by rBPI23.

Glutamine-enriched enteral feeding in trauma patients: reduced infectious morbidity is not related to changes in endocrine and metabolic responses

BACKGROUND

Recently we have shown that glutamine-enriched enteral nutrition in trauma patients reduced the occurrence of pneumonia, bacteremia, and sepsis. In that study, no clear explanation for these results was found except for lower tumor necrosis factor (TNF)-soluble receptors, suggesting immunomodulation. Here we present data on the course of endocrine and metabolic plasma mediators that were analyzed to provide more insight into the working mechanism of glutamine.

METHODS

Endocrine and metabolic mediators were measured in plasma samples taken on admission (day 0) and on days 1, 2, 3, 7, and 10. Glucose, prealbumin, albumin, alanine, C-reactive protein, alpha1-antitrypsin, complement factors, cortisol, glucagon, insulin, and growth hormone were assessed by standard techniques.

RESULTS

The rate of feeding, demography, and injury severity did not differ between the glutamine and control group. There was a sustained hyperglycemic response in both groups. Insulin levels rose in the second phase of the period of observation. A moderate cortisol and glucagon response was seen in both groups. There was no alteration in growth hormone levels in either group. C-reactive protein, alpha1-antitrypsin, and complement factors showed similar increases in both groups but levels remained in the normal range. The course of alanine, albumin, and prealbumin also showed no difference between the groups.

CONCLUSIONS

Glutamine-enriched enteral nutrition had no influence on the endocrine and metabolic response in trauma patients. Therefore, the reduction in infectious morbidity seen in glutamine-supplemented trauma patients is most likely not explained by a modulation of the humoral stress response and its metabolic consequences.

The impact of nutritional status on the prognoses of patients with advanced head and neck cancer

BACKGROUND

Malnutrition has been recognized as a poor prognostic indicator for cancer treatment-related morbidity and mortality in general, and it is reported to affect 30-50% of all patients with head and neck cancer. In this study, the correlation of nutritional status with 3-year survival was studied prospectively in 64 patients with T2-T4 carcinomas of the head and neck who were treated surgically with curative intent; the surgery was often followed by radiotherapy.

METHODS

All patients underwent nutritional screening according to six different parameters on the day prior to surgery. Overall and disease specific survival analyses were performed with a follow-up period of at least 3 years. Survival analyses were performed with the log rank test and the Cox proportional hazards model.

RESULTS

Lymph node stage, nonradical resection margins, and occurrence of major postoperative complications were demonstrated to affect disease specific survival for the group as a whole. None of the investigated nutritional parameters were correlated with survival. When men and women were analyzed separately, however, a preoperative weight loss of >5% did have a prognostic value for men. The combination of male gender, preoperative weight loss, and major postoperative complications were related to early death.

CONCLUSIONS

Apart from the well-known prognostic parameters lymph node status (T classification) and status of surgical margins, preoperative weight loss and occurrence of major postoperative complications were also found to have a negative effect on the survival of male patients undergoing surgery for advanced head and neck cancer.

A prospective randomized study of the systemic immune response after laparoscopic and conventional Nissen fundoplication

BACKGROUND

Laparoscopic techniques are thought to reduce the postoperative immunologic and metabolic changes of conventional operations. Until now, the only clinical data available were obtained from patients operated on for symptomatic gallstones; moreover, few studies were randomized. This randomized prospective study compares the systemic immune response after laparoscopic and conventional Nissen fundoplication.

METHODS

Seventeen patients scheduled for Nissen fundoplication were randomly assigned to undergo either a laparoscopic or a conventional procedure. Postoperative inflammatory response was assessed by measuring the white blood cell count, C-reactive protein, and soluble tumor necrosis factor receptors p55 and p75. Postoperative immune function was assessed by measuring monocyte HLA-DR expression and the stress response was assessed by measuring plasma cortisol concentrations.

RESULTS

Laparoscopic surgery resulted in significantly lower plasma CRP levels 1 day after surgery. Both approaches resulted in a significant decrease in HLA-DR expression within 2 hours after surgery. After the laparoscopic approach, postoperative expression was restored to preoperative values within 1 day after surgery. However, after conventional surgery HLA-DR expression remained suppressed and did not return to preoperative values until the fourth postoperative day. No significant differences between the 2 procedures were observed in white cell blood count, sTNFr-p55 and p75, nor in postoperative cortisol levels.

CONCLUSIONS

Although both laparoscopic and conventional Nissen fundoplication result in an activation of the systemic immune response, this study suggests that this response could be less after the laparoscopic approach. The differences found may reflect a lower risk for postoperative infective complications.

Is major liver surgery associated with an increased systemic inflammatory response? A prospective comparison of hemihepatectomy and other major abdominal surgery

AIMS/BACKGROUND

Extensive liver resection is associated with a higher morbidity and mortality than other major abdominal surgery. Because the liver is responsible for the clearance of pathogenic particles as well as the clearance and degradation of several inflammatory mediators, the high rate of complications after liver surgery may be due to an enhanced or prolonged inflammatory response. The objective of this prospective study was to investigate whether major liver resection is associated with an enhanced systemic inflammatory response.

METHODS

The course of various inflammatory parameters was studied in 12 patients undergoing a hemihepatectomy and the results were compared with those of 12 patients undergoing other major abdominal surgery.

RESULTS

After hemihepatectomy, the plasma levels of IL-6, IL-8, sPLA2 and elastase were similar to the levels after other major abdominal surgery, though the hepatectomized patients showed higher levels of lactoferrin, possibly due to impaired hepatic clearance. In addition, the hemihepatectomized patients showed signs of impaired liver function, as was indicated by increased plasma bilirubin and ASAT levels, whereas the other patients did not.

CONCLUSIONS

The inflammatory response associated with major liver resection is not significantly different from that after other major abdominal surgery, and therefore does not explain the increased complication rate that is seen after major liver resection. We infer that the most important factor in the development of complications after liver resection may be the hepatic failure itself.

Impaired leukocyte phagocytosis in patients undergoing hemihepatectomy for liver metastases

Patients undergoing partial hepatectomy have an increased susceptibility to infection. To investigate whether this increased risk is related to impaired leukocyte function, we studied polymorphonuclear leukocyte (PMN) phagocytosis in patients undergoing a hemihepatectomy because of liver metastasis (LM, n = 11) and in patients undergoing major abdominal surgery because of abdominal malignancy (AM, n = 8). Eight healthy volunteers (HVs) served as controls. Leukocyte suspensions were incubated with fluorescein isothiocyanate-labeled Staphylococcus aureus, and phagocytosis was measured by flow cytometry. Preoperative PMN phagocytosis, in the presence of autologous plasma, was significantly less in patients with LM compared with patients with AM or HVs. This impaired phagocytosis was potentially restored in the presence of normal plasma. The decreased phagocytic capacity of PMNs from patients with LM was not related to levels of known plasma opsonins or phenotypic changes of PMNs. Rather, it was related to a deficiency of unidentified plasma factors. After surgery, the phagocytic capacity of PMNs of patients with AM decreased by approximately 30%, which correlated with decreasing levels of immunoglobulin G and C3. In conclusion, patients with LM had a decreased PMN phagocytic capacity before surgery. This impairment in phagocytosis disappeared 1 week after surgery. We propose that the presence of LM leads to a deficiency of factor(s) in the blood that impairs PMN phagocytic capacity.

Glutamine reduces phorbol-12,13-dibutyrate-induced macromolecular hyperpermeability in HT-29Cl.19A intestinal cells

BACKGROUND

Loss of mucosal integrity is associated with intestinal hyperpermeability, which may be inhibited by glutamine. The nature of this effect is unknown. The effect of glutamine on protein kinase C (PKC)-mediated hyperpermeability in HT-29Cl.19A intestinal cells was studied.

METHODS

Confluent monolayers of HT-29C1.19A cells were cultured on permeable filters and mounted in Ussing chambers for permeability studies. Apical to basolateral transepithelial permeability for intact horseradish peroxidase (HRP) was determined. Phorbol-12,13-dibutyrate (PDB) was used to activate PKC-mediated hyperpermeability, and the effect of glutamine (0.6 mmol/L) was studied.

RESULTS

Two hours of PDB stimulation increased the HRP flux, reaching five times control values after 4 hours. Bilateral exposure to glutamine for 4 hours reduced PDB-induced hyperpermeability (37%). Preincubation with glutamine 2 hours before PDB stimulation showed an earlier and greater effect (3 hours, 43%; 4 hours, 50%). This bilateral effect of glutamine was mimicked by separate apical exposure. Basolateral exposure alone had no effect.

CONCLUSIONS

Glutamine rapidly reduced the PKC-mediated hyperpermeability for HRP in HT-29Cl.19A intestinal cells. The dependency on apical exposure suggests that glutamine may be more effective when delivered by the enteral route.

Reduced arginine plasma levels are the drive for arginine production by the kidney in the rat

In bile duct ligated rats, arginase (ASE) release from damaged hepatocytes results in low arginine (ARG) levels despite maximal renal ARG production. Plasma ARG levels were restored by reducing gut-derived endotoxemia that lowered circulating ASE activity although maintaining increased renal production. From this it was not clear if the higher renal ARG production was induced by the low grade endotoxemia or the low arginine plasma levels. The separate and combined influence of both factors on ARG metabolism was studied in the rat. Male Wistar rats received either bovine liver ASE, to lower ARG levels, or saline (SAL). Following the ASE or SAL infusion, rats were randomized to receive a low dose endotoxin (LPS) or SAL infusion. In ASE/SAL- and ASE/LPS-treated rats, ARG levels were lower compared with SAL/SAL (p<.005) and SAL/LPS (p<.005). The increased ARG production by the kidneys and gut proved to be independent of LPS but related to reduced ARG plasma levels (both p<.05 when compared with SAL/SAL and SAL/LPS). Metabolism of related amino acids was not explanatory. The study concluded that a low grade endotoxemia did not influence the metabolism of ARG by the gut, kidney, and liver. Reductions in ARG plasma by ASE treatment, irrespective a low dose endotoxin, were the drive for ARG production by the gut and the kidney.

Randomised trial of glutamine-enriched enteral nutrition on infectious morbidity in patients with multiple trauma

BACKGROUND

Infections are an important cause of morbidity and mortality in patients with multiple trauma. Studies in both animals and human beings have suggested that glutamine-enriched nutrition decreases the number of infections.

METHODS

Patients with multiple trauma with an expected survival of more than 48 h, and who had an Injury Severity Score of 20 or more, were randomly allocated glutamine supplemented enteral nutrition or a balanced, isonitrogenous, isocaloric enteral-feeding regimen along with usual care. Each patient was assessed every 8 h for infection, the primary endpoint. Data were analysed both per protocol, which included enteral feeding for at least 5 days, and by intention to treat.

FINDINGS

72 patients were enrolled and 60 received enteral feeding (29 glutamine-supplemented) for at least 5 days. Five (17%) of 29 patients in the glutamine-supplemented group had pneumonia compared with 14 (45%) of 31 patients in the control group (p<0.02). Bacteraemia occurred in two (7%) patients in glutamine group and 13 (42%) in the control group (p<0.005). One patient in the glutamine group had sepsis compared with eight (26%) patients in the control group (p<0.02).

INTERPRETATION

There was a low frequency of pneumonia, sepsis, and bacteraemia in patients with multiple trauma who received glutamine-supplemented enteral nutrition. Larger studies are needed to investigate whether glutamine-supplemented enteral nutrition reduces mortality.

Pharmacokinetics of a recombinant amino terminal fragment of bactericidal/permeability increasing protein (rBPI21) after liver surgery in rats and humans

Major liver resections are associated with considerable morbidity and mortality. Gut-derived bacteria and bacterial endotoxin (LPS) are considered to play a central role in the pathophysiology of these complications. Like human BPI, rBPI21 binds to LPS from Gram-negative bacteria. By binding and clearing of LPS, rBPI21 can inhibit a number of endotoxin-induced humoral and cellular responses. Because of this capacity, rBPI21 could partially compensate for the loss of hepatic mononuclear phagocytic system function after liver resection. However, the liver is also thought to be an important organ for the clearance of BPI, and reduction of liver mass could result in a decreased clearance and exceedingly high plasma levels of rBPI21. In this study we therefore investigated the pharmacokinetics of rBPI21 in rats and in patients undergoing a major liver resection. Rats were administered an intravenous (i.v.) bolus of rBPI21 after undergoing a 60% or 80% hepatectomy (with sham-operated controls). Patients undergoing a hemihepatectomy and healthy volunteers received rBPI21 or placebo by continuous i.v. infusion for 48 h. Plasma concentrations were measured by sandwich ELISA. In rats, 60% hepatectomy did not consistently change the clearance of rBPI21, whereas 80% hepatectomy decreased the clearance of rBPI21 severalfold. In hemihepatectomized patients, the clearance of rBPI21 after major hepatectomy was also slower, when compared with healthy volunteers, but this difference had disappeared within 24 h. Our data indicate that the administration of rBPI21 in patients undergoing liver resection is well tolerated and does not result in exceedingly high plasma levels. Additional studies on the efficacy of rBPI21 in the prevention of complications after hepatectomy are needed.

Differences in immune status between well-nourished and malnourished head and neck cancer patients

Malnutrition is reported to occur in approximately 30% of head and neck cancer patients. Also, impaired immunocompetence is described as a common phenomenon in this patient group. The purpose of this study was to assess the possible relationship between malnutrition and some prognostically important immune parameters in head and neck cancer patients. Thirty-two malnourished (recent weight loss >/= 10%) and 34 well-nourished patients undergoing curative treatment for advanced head and neck cancer were studied prospectively, and six parameters of their immune status (leucocytes, lymphocytes, lymphocyte phenotyping, monocytes, HLA-DR expression on monocytes and serum interleukin-10) were determined on the day of panendoscopy. Reference values for monocytes, HLA-DR expression and interleukin-10 were obtained from 43 healthy controls. Although the number of monocytes was elevated in both patient groups, the HLA-DR expression on these monocytes was significantly lower in the malnourished than in the well-nourished and control groups. Tumor stage, tumor localization, recurrence after initial radiotherapy, age and gender were not correlated to HLA-DR expression. No relationships emerged between nutritional status and lymphocyte subsets. Malnourished head and neck cancer patients show a significantly lower HLA-DR expression on monocytes than well-nourished ones and healthy controls. According to the literature this would imply an increased risk for postoperative complications. Indeed, postoperative complications occur more frequently in malnourished than in well-nourished patients.

Paradoxical changes in organ blood flow after arginase infusion in the non-stressed rat

Arginine (ARG) is the precursor of nitric oxide (NO), a potent vasodilator. Arginase (ASE) is released following hepatocellular damage, resulting in low plasma ARG levels. The effect of ASE infusion on hemodynamics was studied. Rats received a 20 min ASE or saline infusion, and systemic hemodynamics and organ blood flow were studied, at 30 and 270 min, using radiolabeled microspheres. Compared with control, ASE resulted (30 min) in 1) undetectable ARG levels; 2) higher mean arterial pressure and total peripheral resistance (both p < .05); 3) higher blood flow to the heart, kidneys, stomach, small intestine (all p < .05), and spleen (p < .001); and 4) lower vascular resistance in the heart, kidneys, stomach, and small intestine (all p < .05) and in the spleen (p < .005). At 270 min, ASE rats had similar organ blood flow and higher nitrate levels in urine and plasma (both p < .05) compared with control. We conclude that ASE reduces ARG levels with simultaneous increase in mean arterial pressure and total peripheral resistance. Higher nitrate production, suggesting higher NO formation in the presence of low ARG plasma levels, is paradoxical but could explain the higher blood flow in some organs. The increased total peripheral resistance during higher nitrate formation suggests regional differences in dependency of NO production on plasma ARG levels.

Gut endotoxin restriction improves postoperative hemodynamics in the bile duct-ligated rat

BACKGROUND

Postoperative hemodynamic disturbances in obstructive jaundice are associated with complications such as shock and renal failure. Gut-derived endotoxemia may underlie these complications. Recently, we have shown that cholestyramine treatment prevents gut-derived endotoxemia in bile duct-ligated (BDL) rats (Houdijk APJ, Boermeester MA, Wesdorp RIC, Hack CE, van Leeuwen PAM: Tumor necrosis factor unresponsiveness following surgery in bile duct-ligated rats. Am J Physiol 271: G980-G986, 1996).

METHODS

The effect of cholestyramine on systemic hemodynamics and organ blood flows after a laparotomy was studied in 2 wk BDL rats using radioactive microspheres.

RESULTS

Compared with sham-operated rats, postoperative BDL rats had 1) lower blood pressure (p < .05) and heart rate (p < .001) with higher cardiac output (p < .05), 2) lower splanchnic blood flow (p < .05), 3) lower renal blood flow (p < .01), and 4) higher splanchnic organ and renal-vascular resistances. Cholestyramine treatment in BDL rats prevented the postoperative decrease in blood pressure by increasing cardiac output (p < .01). In addition, cholestyramine maintained splanchnic blood flow at sham levels (p < .05). Furthermore, cholestyramine also prevented the fall in renal blood flow after surgery in BDL rats.

CONCLUSION

Gut endotoxin restriction using cholestyramine treatment maintained normal blood pressure, improved splanchnic blood flow, and completely prevented the fall in renal blood flow in BDL rats. Reducing the gut load of endotoxin in patients with obstructive jaundice scheduled for abdominal surgery may prevent postoperative hemodynamic complications.

Use of a mixture of medium-chain triglycerides and longchain triglycerides versus long-chain triglycerides in critically ill surgical patients: a randomized prospective double-blind study

Twenty critically-ill surgical patients who needed total parenteral nutrition were randomly enrolled in a double-blind study comparing two intravenous fat emulsions: one containing a mixture of 50% medium-chain triglycerides and 50% long-chain triglycerides and another containing 100% longchain triglycerides. The purpose of this study was to investigate metabolic and biochemical differences between both emulsions with special reference to liver enzymes. After a baseline period of 24 h with only glucose and NaCl infusion, the lipid emulsion was added continuously during 24 h over 5 days. The parenteral nutrition was administered in mixture bags containing amino-acids, glucose and lipids together. Two-thirds of the non-protein calories were administered as glucose 40% and one third as either long-chain triglycerides or a mixture of medium-chain triglycerides and long-chain triglycerides. The total amount of non-protein calories received was the measured energy expenditure during the baseline period plus 10% and was fixed during the study. Plasma substrate concentrations, energy expenditure, and nitrogen balance were determined and arterial blood samples were taken. No toxic effects or complications attributable to one of the two emulsions were observed. There was no significant difference in energy expenditure, nitrogen balance, liver function tests, carnitine, transferrin, pre-albumin, albumin, cholesterol, triglycerides and free fatty acids. The only parameter that showed a different pattern of reaction between the two emulsions was serum bilirubin concentration. In this study no evidence of any advantageous effect of a mixture of medium-chain triglycerides and long-chain triglycerides was seen.

Dietary glutamine supplementation reduces plasma nitrate levels in rats

It was recently shown that L-glutamine inhibits vascular nitric oxide (NO) production in vitro. The present study investigated the effect of glutamine enriched enteral diets on in vivo NO production in the rat. Nitrate, the stable end-product of NO production, was measured in plasma and 24 h urine collections in glutamine supplemented rats (6.25%, 12.5% and 25% w/w) and compared to the effect of isocaloric, nitrogenous control diets. Glutamine supplementation increased plasma levels of glutamine (up to 91%), arginine (up to 17%) and citrulline (up to 54%). After 1 week of glutamine supplementation plasma nitrate levels were significantly reduced by 50% compared to control (P < 0. 0001); irrespective of the amount of supplementation. No further decrease was observed after 2 weeks of feeding. No differences in daily urinary losses were found between the groups. These results point to an in vivo inhibitory effect of glutamine supplemented enteral feeding on NO production.

Arginine deficiency in bile duct-ligated rats after surgery: the role of plasma arginase and gut endotoxin restriction

BACKGROUND & AIMS

Arginine deficiency may underlie the cellular immune depression after surgery in obstructive jaundice, which is associated with gut-derived endotoxemia. The aim of this study was to study arginine metabolism in the bile duct-ligated rat (BDL) after laparotomy.

METHODS

Treatment with cholestyramine, a known endotoxin binder, was used to evaluate the role of gut-derived endotoxemia.

RESULTS

In BDL rats, arginine levels were lower compared with those in sham-operated controls (P < 0.005), despite a three-fold increase in renal arginine release (P < 0.01). Liver and gut arginine handling also could not explain the reduced arginine levels. Higher plasma arginase activity (P < 0.0001) was measured in BDL rats, explaining both the lower arginine levels (r = 0.73, P < 0.01) and the increase in arginase product levels: ornithine (P < 0.005 and r = 0.72; P < 0.01) and urea (P < 0.01). Cholestyramine treatment prevented the decrease in postoperative arginine deficiency by reducing plasma arginase activity by 43% (P < 0.005). In addition, it significantly lowered plasma levels of the other liver enzymes (aspartate transaminase, alanine transaminase, gamma-glutamyl transpeptidase, and alkaline phosphatase; P < 0.05) in BDL rats.

CONCLUSIONS

The study concluded that arginine deficiency in BDL rats after surgery is caused by high plasma liver arginase activity. Cholestyramine prevented the arginine deficiency by reducing plasma arginase activity through the inhibition of additional endotoxin-mediated hepatocellular damage after surgery in BDL rats.

Assessment of malnutrition parameters in head and neck cancer and their relation to postoperative complications

BACKGROUND

Malnutrition is reported frequently in head and neck cancer patients. The impact of malnutrition on surgical outcome is not clearly understood. The purpose of this study was to define the usefulness of six different parameters in scoring malnutrition and to determine the nutritional parameter primarily related to postoperative complications.

METHODS

Sixty-four patients undergoing major surgery for advanced head and neck cancer were studied prospectively, and six different parameters were used to define malnutrition. Logistic regression was used to relate nutritional parameters to postoperative complications.

RESULTS

The parameters applied all identified different aspects of the nutritional status, as malnutrition varied between 20% and 67%. Logistic regression analysis identified a weight loss of more than 10% to be the most prominent predictive parameter for the occurrence of major postoperative complications.

CONCLUSIONS

Patients with weight loss more than 10% during the six months before surgery are at a great risk for the occurrence of major postoperative complications.

Assessment of malnutrition parameters in head and neck cancer and their relation to postoperative complications

BACKGROUND

Malnutrition is reported frequently in head and neck cancer patients. The impact of malnutrition on surgical outcome is not clearly understood. The purpose of this study was to define the usefulness of six different parameters in scoring malnutrition and to determine the nutritional parameter primarily related to postoperative complications.

METHODS

Sixty-four patients undergoing major surgery for advanced head and neck cancer were studied prospectively, and six different parameters were used to define malnutrition. Logistic regression was used to relate nutritional parameters to postoperative complications.

RESULTS

The parameters applied all identified different aspects of the nutritional status, as malnutrition varied between 20% and 67%. Logistic regression analysis identified a weight loss of more than 10% to be the most prominent predictive parameter for the occurrence of major postoperative complications.

CONCLUSIONS

Patients with weight loss more than 10% during the six months before surgery are at a great risk for the occurrence of major postoperative complications.

Gut endotoxin restriction prevents catabolic changes in glutamine metabolism after surgery in the bile duct-ligated rat

OBJECTIVE

The objective of this study was to investigate the role of gut-derived endotoxemia in postoperative glutamine (GLN) metabolism of bile duct-ligated rats.

SUMMARY BACKGROUND DATA

Postoperative complications in patients with obstructive jaundice are associated with gut-derived endotoxemia. In experimental endotoxemia, catabolic changes in GLN metabolism have been reported. Glutamine balance is considered important in preventing postsurgical complications.

METHODS

Male Wistar rats were treated orally with the endotoxin binder cholestyramine (n = 24, 150 mg/day) or saline (n = 24). On day 7, groups received a SHAM operation or a bile duct ligation (BDL). On day 21, all rats were subjected to a laparotomy followed 24 hours later by blood flow measurements and blood sampling. Glutamine organ handling was determined for the gut, liver, and one hindlimb. Intracellular GLN muscle concentrations were determined.

RESULTS

Compared to the SHAM groups, BDL rats showed lower gut uptake of GLN (28%, p < 0.05); a reversal of liver GLN release to an uptake (p < 0.05); higher GLN release from the hindlimb (p < 0.05); and lower intracellular muscle GLN concentration (32%, p < 0.05). Cholestyramine treatment in BDL rats maintained GLN organ handling and muscle GLN concentrations at SHAM levels.

CONCLUSIONS

Disturbances in postoperative GLN metabolism in BDL rats can be prevented by gut endotoxin restriction. Gut-derived endotoxemia after surgery in obstructive jaundice dictates GLN metabolism.

Endotoxin and interleukin-1 related hepatic inflammatory response promotes liver failure after partial hepatectomy

Impairment of various functions of the liver and concomitantly increased levels of parameters of liver damage, a clinical entity termed liver failure, is commonly seen after partial hepatectomy. We investigated in a rat model whether damage of the remnant liver was due to local inflammatory responses, and related to endotoxin or interleukin-1 (IL-1). To address this question, the effects of partial hepatectomy on infiltration of immunocompetent cells and expression of major histocompatibility complex (MHC) class II antigen of macrophages in the remnant liver was studied using immunohistochemical techniques. Specific intervention with recombinant N-terminal bactericidal/permeability-increasing protein (rBPI23) to neutralize endotoxin and with IL-1 receptor antagonist (IL-1ra) to block IL-1 activity was used to examine the respective roles of endotoxin and IL-1. After partial hepatectomy, we found an influx of neutrophils, an increased expression of MHC class II antigens, and morphologic changes of Kupffer cells consistent with activation. These inflammatory events coincided with increased serum levels of markers of liver damage (aspartate aminotransferase, alanine aminotransferase, ammonia). Both neutralization of endotoxin and blocking of IL-1 activity reduced hepatic inflammation and reduced serum levels of aminotransferases and ammonia. In addition, liver cell proliferation as assessed by staining for proliferating cell nuclear antigen (PCNA) expression was significantly enhanced when either endotoxin or IL-1 effects were blocked. Thus, our results suggest that local hepatic inflammatory responses inhibit liver cell proliferation and promote liver failure, presumably by affecting the functional capacity of the remnant liver.

Interleukin-1 blockade attenuates mediator release and dysregulation of the hemostatic mechanism during human sepsis

OBJECTIVE

To define the influence of interleukin-1 activity on coagulation and fibrinolytic system activation and the release of proinflammatory mediators in the early human response to severe infection.

STUDY DESIGN

All patients with severe sepsis syndrome who were enrolled from two surgical centers that were participating in a randomized, double-blind, placebo controlled, multicenter, multinational trial of recombinant human interleukin-1 receptor antagonist in the treatment of sepsis syndrome.

POPULATION

Twenty-six patients with sepsis syndrome received an intravenous loading dose of recombinant human interleukin-1 receptor antagonist (100 mg) or placebo followed by a continuous 72-hour infusion of recombinant human interleukin-1 receptor antagonist (1.0 [n = 9] or 2.0 [n = 8] mg/kg per hour) or placebo (n = 9).

OUTCOME MEASURE

Responses up to 72 hours after initiation of treatment.

RESULTS

Plasma levels of the anaphylatoxin C3a and thrombin-antithrombin III complexes were reduced in the high-dose recombinant human interleukin-1 receptor antagonist treatment group after 72 hours (P < .05). Similarly, parameters of fibrinolysis, tissue-type plasminogen activator, and plasminogen activator inhibitor type 1 but not plasmin-alpha 2-antiplasmin complexes, were also significantly reduced (P < .05) after 72 hours of treatment with a high dose of recombinant human interleukin-1 receptor antagonist. Neutrophil elastase-alpha 1-antitrypsin complexes and phospholipase A2 levels were also significantly reduced in the high-dose recombinant human interleukin-1 receptor antagonist treatment group after 72 hours.

CONCLUSIONS

The results confirm that activation of the coagulation and fibrinolytic systems and release of soluble inflammatory mediators are consistently observed in patients with severe sepsis syndrome. Interleukin-1 activity contributes to activation of these processes as documented by the reduction in surrogate activation markers during recombinant human interleukin-1 receptor antagonist treatment.

Glutamine-enriched enteral diet increases renal arginine production

BACKGROUND

Arginine (Arg) is generated in the kidney by the conversion of circulating citrulline. The most important source for circulating citrulline is the metabolism of glutamine (Gln) by the gut. In this study, we investigated the influence of an enteral diet enriched with Gln on renal Arg synthesis in the rat.

METHODS

Rats were fed a 12.5% Gln-enriched diet or an isocaloric, isonitrogenous control diet for 14 days. Kidney plasma flow and arterial and renal venous plasma levels of a number of amino acids were measured, and kidney amino acid fluxes were calculated.

RESULTS

Compared with the control diet, Gln enrichment resulted in significantly higher arterial plasma levels of circulating citrulline (30%, p < .0001) and Arg (31%, p < .0005). The uptake of circulating citrulline and the subsequent production of Arg by the kidneys were significantly higher in the Gln-enriched group (40% and 38%, respectively) and showed an equimolar relationship in both the control (r = .84, p < .0001) and the Gln-enriched group (r = .83, p < .0001).

CONCLUSIONS

The findings indicate that enteral Gln supplementation caused significantly increased arterial plasma levels of Arg as a result of increased renal Arg production from circulating citrulline. Considering the multiple important biologic properties of Arg, the reported beneficial effects of Gln in catabolic states might be explained in part by increased renal Arg production.

Plasma amino acids determined by liquid chromatography within 17 minutes

We present an HPLC method for the determination of amino acids in plasma. The method is based on automated precolumn derivatization of amino acids with o-phthalaldehyde, separation of the derivatives by reversed-phase chromatography, and quantification by fluorescence detection. Complete separation was achieved within 12 min. Total analysis time, including derivatization, chromatography, and reequilibration of the column, was 17 min. The assay was linear from 5 to 800 mumol/L for all amino acids. Recovery of amino acids added to plasma samples was 96-106%, except for tryptophan (89%). Within-run precision (CV) was 1.8-6.4%, and between-run precision was 2.1-7.2%. The method can be used for determining primary amino acids in plasma and cerebrospinal fluid. The simple sample preparation and short analysis time make the method particularly suitable for routine analysis of large series of samples.

Plasma amino acids determined by liquid chromatography within 17 minutes

We present an HPLC method for the determination of amino acids in plasma. The method is based on automated precolumn derivatization of amino acids with o-phthalaldehyde, separation of the derivatives by reversed-phase chromatography, and quantification by fluorescence detection. Complete separation was achieved within 12 min. Total analysis time, including derivatization, chromatography, and reequilibration of the column, was 17 min. The assay was linear from 5 to 800 mumol/L for all amino acids. Recovery of amino acids added to plasma samples was 96-106%, except for tryptophan (89%). Within-run precision (CV) was 1.8-6.4%, and between-run precision was 2.1-7.2%. The method can be used for determining primary amino acids in plasma and cerebrospinal fluid. The simple sample preparation and short analysis time make the method particularly suitable for routine analysis of large series of samples.