Effect of surgical trauma on plasma concentrations of cyclic AMP and cortisol

Epidural administration of large dose of opioid μ receptor agonist may impair cardiac functions and myocardial viability via desensitizing transient receptor potential vanilloid 1

The incidence of postoperative myocardial injury remains high as the underlying pathogenesis is still unknown. The dorsal root ganglion (DRG) neurons express transient receptor potential vanilloid 1 (TRPV1) and its downstream effector, calcitonin gene-related peptide (CGRP) participating in transmitting pain signals and cardiac protection. Opioids remain a mainstay therapeutic option for moderate-to-severe pain relief clinically, as a critical component of multimodal postoperative analgesia via intravenous and epidural delivery. Evidence indicates the interaction of opioids and TRPV1 activities in DRG neurons. Here, we verify the potential impairment of myocardial viability by epidural usage of opioids in postoperative analgesia. We found that large dose of epidural morphine (50 μg) significantly worsened the cardiac performance (+dP/dtmax reduction by 11% and -dP/dtmax elevation by 24%, all P < 0.001), the myocardial infarct size (morphine vs Control, 0.54 ± 0.09 IS/AAR vs. 0.23 ± 0.06 IS/AAR, P < 0.001) and reduced CGRP in the myocardium (morphine vs. Control, 9.34 ± 2.24 pg/mg vs. 21.23 ± 4.32 pg/mg, P < 0.001), while induced definite suppression of nociception in the postoperative animals. It was demonstrated that activation of μ-opioid receptor (μ-OPR) induced desensitization of TRPV1 by attenuating phosphorylation of the channel in the dorsal root ganglion neurons, via inhibiting the accumulation of cAMP. CGRP may attenuated the buildup of ROS and the reduction of mitochondrial membrane potential in cardiomyocytes induced by hypoxia/reoxygenation. The findings of this study indicate that epidurally giving large dose of μ-OPR agonist may aggravate myocardial injury by inhibiting the activity of TRPV1/CGRP pathway.

Biochemistry of uridine in plasma

Uridine is a pyrimidine nucleoside that plays a crucial role in synthesis of RNA, glycogen, and biomembrane. In humans, uridine is present in plasma in considerably higher quantities than other purine and pyrimidine nucleosides, thus it may be utilized for endogenous pyrimidine synthesis. Uridine has a number of biological effects on a variety of organs with or without disease, such as the reproductive organs, central and peripheral nervous systems, and liver. In addition, it is used in clinical situations as a rescue agent to protect against the adverse effects of 5-fluorouracil. Since the biological actions of uridine may be related to its plasma concentration, it is important to examine factors that have effects on that concentration. Factors associated with an increase in plasma concentration of uridine include enhanced ATP consumption, enhanced uridine diphosphate (UDP)-glucose consumption via glycogenesis, inhibited uridine uptake by cells via the nucleoside transport pathway, increased intestinal absorption, and increased 5-phosphribosyl-1-pyrophosphate and urea synthesis. In contrast, factors that decrease the plasma concentration of uridine are associated with accelerated uridine uptake by cells via the nucleoside transport pathway and decreased pyrimidine synthesis.

Lymphocytic subpopulation changes after open and laparoscopic cholecystectomy: a prospective and comparative study on 38 patients

Up to now it has been unclear whether laparoscopic surgery has fewer immunosuppressive effects than traditional laparotomic procedures. In a series of 38 patients affected by symptomatic gallstone disease and operated on either by laparoscopy (group 1) or by traditional open surgery (group 2), we determined the postoperative changes in lymphocyte subpopulations up to postoperative day (POD) 30. We collected 15 ml of venous blood from all patients in both groups on the day before surgery and on POD 1, 7, 15, and 30. A control group (group 3) comprised 56 healthy volunteers; the control group was used only to ensure that baseline values were totally comparable with a normal population; only one blood sample was obtained from the subjects in group 3. Patients undergoing open cholecystectomy had a significant decrease in total lymphocyte count on POD 1. Basal levels of lymphocyte subpopulations did not differ significantly in the study and control groups. No differences were found in the preoperative lymphocyte cell counts in the two groups who underwent cholecystectomy. Pan-T cells (CD3) showed a statistically significant marked reduction throughout the observation period. The counts of helper (CD4), suppressor (CD8), and natural killer NK (CD16) T cells were reduced on POD 1; the NK cell (CD16) count remained low until POD 30, B lymphocytes showed no postoperative reduction. In patients who underwent laparoscopic cholecystectomy, a significant postoperative decrease in total lymphocyte count, and in CD3, CD4, and CD8 subpopulations was observed on day 1 only. There was no reduction in CD16 and CD19 subpopulations. A comparative statistical analysis of lymphocyte subpopulations in the two groups was carried out: In the open cholecystectomy group, compared with the laparoscopy group, CD3, CD4, CD8, and CD16 lymphocyte subpopulations showed marked reductions at different time points. In particular, statistically significant differences were found in CD3 levels from POD 1 through POD 30, in CD4 from day 1 through day 7, and in CD8 and CD16 only on day 1.

Impact of thymopentin on the incidence and severity of postoperative infection: a randomized controlled trial

The effectiveness of perioperative administration of thymopentin in preventing postoperative infection was evaluated in 206 patients with cancer (54 gastric, 152 colorectal) who underwent elective major surgery. Comparable subsets of patients were obtained with respect to age (proportion over 65 years) and nutritional status (patients with serum albumin level less than 30 milligrams or weight loss of 10 per cent or more of usual body-weight were considered to be malnourished). Patients were then randomly assigned to a control group or to a group receiving thymopentin. All patients received perioperative short-term antibiotic prophylaxis and postoperative parenteral nutrition. Levels of CD3-, CD4- and CD8-positive T cell subsets were evaluated before and after surgery in 20 (ten elderly) patients from each group. The severity of postoperative infection was evaluated using a sepsis score. In elderly patients thymopentin prevented the postoperative drop in CD3- and CD4-positive T cell subpopulations that was observed in controls (P < 0.05d). The postoperative infection rate was 17.5 per cent in the group given thymopentin and 24.3 per cent in controls (P not significant). The mean (s.d.) sepsis score was 6.7 (3.1) in the group receiving thymopentin and 9.4 (5.8) in controls (P not significant). Considering only elderly patients, the mean (s.d.) sepsis score was significantly lower in those treated with thymopentin than in control patients (6.9(2.1) versus 11.3(4.7)). In conclusion, administration of thymopentin did not significantly reduce the postoperative infection rate. However, it prevented the drop in number of CD3- and CD4-positive T cells after operation and reduced the severity of postoperative infection in elderly patients.

Thyroid hormone profiles in experimental acute renal failure

Thyroid hormone profiles were determined in two groups of dogs made uremic, either by i.v. uranyl nitrate 10 mg/kg BW injection or by bilateral ureteral ligation, and in one group of sham-operated animals. Each group consisted of 6 dogs and served as its own control. From blood samples taken in 12-h intervals up to 144 h for uranyl nitrate-injected dogs and 96 h for operated dogs, serum levels of T4, T3, fT4, fT3, rT3, and cortisol were measured by radioimmunoassays. The results obtained in both groups of uremic dogs showed an initial sharp fall of T4, T3, fT4, and fT3 followed by a plateau or retarded decrease. In sham-operated dogs the fall of these hormones was slight and of short duration. Reverse T3 had a tendency to increase in all groups examined, but a significant elevation was recorded only after bilateral ureteral ligation. In this group cortisol serum levels were found the highest, being also significantly increased in the other two groups. The temporal coincidence of the most marked alterations in T3, rT3, and cortisol serum concentrations indicates a significant role of stress in thyroid dysfunction. Although serum creatinine rise and weight loss were not parallel with thyroid hormone alterations, the involvement of uremic compounds and malnutrition in this process is also quite clear. Thus, the data presented suggest simultaneous influences of uremic toxins, stress, and malnutrition on the induction of thyroid dysfunction in dogs made uremic by uranyl nitrate injection or bilateral ureteral ligation.(ABSTRACT TRUNCATED AT 250 WORDS)

The risk factors of median sternotomy infection: a current review

Sternal sepsis following median sternotomy is an infrequent yet devastating complication of cardiac surgery, leading to prolonged hospitalization, increased hospital expense, and a high associated morbidity and mortality. The development of sternotomy infection is multifactorial. Numerous prospective and retrospective studies have pointed to a multitude of clinical and perioperative variables as being causative, with as many other studies presenting evidence of the contrary. This has led to confusion about which clinical variables should be modified so as to minimize the individual patient's risk for developing this severe complication. Other less obvious factors also come into play. Malnutrition, whether overt or subclinical, is not uncommon in cardiac patients. Immune competency is affected by operative trauma, as well as a variety of perioperative factors including underlying nutritional status, transfusion, cardiopulmonary bypass, and anesthesia. This creates a complex milieu for the development of postoperative infection. In this review, the multiple risk factors of median sternotomy infection are studied and treatment options briefly discussed.

The effect of ECT on plasma cyclic nucleotides: a simulated ECT controlled study in melancholic patients

Concentrations of cAMP and cGMP in plasma were measured in 20 drug-free melancholic patients during a simulated electroconvulsive treatment (SECT) and a bilateral ECT session. Blood samples were taken every 15 min beginning 15 min before and ending 60 min after the SECT or the ECT. Two-way ANOVA and paired t-test demonstrated a significant and greater fall in cAMP over time following SECT. ECT induced a marginal increase (P less than 0.05) at 45 min postictally. It is postulated that ECT causes an increase in cAMP levels which is masked by the decrease observed during SECT, caused presumably by the anaesthetic medication. The plasma cGMP levels were increased gradually and significantly after SECT and the same rise was observed during ECT. These effects are discussed in relation to changes in adrenergic-cholinergic activities induced by the medication and the electrical stimulus.

The influence of surgical operations on components of the human immune system

Surgical operations have been shown to cause a variety of immunological disturbances in man both in vivo and in vitro. With few exceptions the overall picture is one of a generalized state of immunodepression in the postoperative period. The implications of these observations are that host defences may be compromised by surgical procedures, thus providing a 'fertile soil' for bacterial invasion and tumour cell metastasis at the very time when risks from invading pathogens and viable tumour cells are maximal. We have studied the effects of surgical operations on the immune system in 35 patients with benign disease. Surgical procedures were classified as either minor (n = 15) or major (n = 20). A panel of monoclonal antibodies was used to identify peripheral blood lymphocyte subpopulations and analysis was performed using flow cytometry. Simultaneous estimations of plasma alpha-1 proteinase inhibitor (alpha-1-PI), alpha-2-macroglobulin (alpha-2-M), alpha-2-pregnancy-associated glycoprotein (alpha-2-PAG) and plasma suppressive activity (PSA) on stimulated allogeneic lymphocytes were performed before operation and on postoperative days 1, 3, 7, 17 and 21. Circulating numbers of all lymphocyte subpopulations fell significantly following surgery, except for B lymphocytes which did not change. The magnitude, and duration of the reduction in cell numbers and the subpopulation affected was significantly related to the degree of surgical trauma, and returned to pre-operative values by postoperative day 7. Changes in alpha-1-PI, alpha-2-M, alpha-2-PAG and PSA were also significantly related to the degree of surgical trauma, and these plasma changes persisted longer than the cellular disturbances. Surgical operations induce a reversible depression of cellular immunity which precedes plasma suppressive activity in its return to pre-operative levels. Immunostimulating agents such as interferon and the interleukins deserve evaluation as prophylactic agents pre-operatively.

Metabolic and hormonal adjustments during hemorrhage in cats after interference with the sympatho-adrenal system

The relative contribution of the splanchnic sympathetic innervation and the adrenal medulla for metabolism and hormone secretion during two different levels of hemorrhagic hypotension was investigated in 3 groups of anesthetized cats, viz, intact, adrenalectomized and splanchnicotomized (adrenalectomy + cutting of splanchnic nerves). In intact cats, hemorrhage caused very marked elevations of arterial plasma glucose, adrenaline, noradrenaline, dopamine, lactate, cAMP, glycerol and glucagon concentrations whereas plasma insulin fell to only 20% of control values. Adrenalectomy attenuated the glucose, adrenaline, noradrenaline and cAMP responses whereas the normal insulin inhibition was abolished. Splanchnicotomy further reduced the hemorrhagic glucose and glycerol responses and, possibly, also that of glucagon. It is concluded that the adrenergic system as a whole is important for the adjustments of the release of glucose, cAMP, glycerol, insulin and glucagon that occur during hemorrhage in cats. The adrenal medulla seems to be of particular importance for the regulation of cAMP release.

Urinary excretion patterns of cyclic AMP and cyclic GMP following thermal injury

Measurement of 24-h urinary cyclic AMP and cyclic GMP levels in 19 patients for up to nine days after thermal injury has revealed differences in cyclic nucleotide excretion patterns between "severe" and "mild to moderate" groups of burned patients, classified according to a predictive index of burn mortality. Cyclic AMP excretion fell significantly from a high initial level in the "severe" group, but showed no significant change in the "mild to moderate" group. Differences in cyclic AMP excretion between the two groups of patients were only significant on the second day following burn injury. There was no correlation between cyclic AMP output averaged for each patient over the first nine days and percentage body surface area of the burn or the predictive index. In contrast to the results for cyclic AMP excretion, cyclic GMP output rose significantly over the 9-day period in severely burned patients, while levels reached a plateau on days four to six for the moderate to mild group. When cyclic GMP excretion was averaged over the first nine days for each patient, a significant correlation with both percent body surface area of burn and the predictive index of burn mortality was found. The tissue source or sources which are responsible for increased cyclic GMP excretion are as yet unknown.

Influence of morphine anaesthesia on the endocrine-metabolic response to open-heart surgery

Twelve patients scheduled for aortic valve replacement during extracorporal circulation were randomly allocated to either morphine anaesthesia or fluroxene anaesthesia. Morphine in a total dose of 4 mg/kg was administered before skin incision. At the start of extracorporal circulation all patients received 25 g glucose intravascularly. The endocrine-metabolic response to surgery, as expressed by changes in plasma ACTH, cortisol, insulin, growth hormone, cyclic adenosine-3',-5'-monophosphate (cyclic AMP), glucose, free fatty acids, blood b-hydroxybutyrate and cumulative nitrogen balance was measured before and during anaesthesia and surgery, and on the first five post-operative days. It was found that morphine anaesthesia blocked the increase in ACTH, cortisol, growth hormone, cyclic AMP, and glucose during surgery. However, after initiation of extracorporal circulation only ACTH, cortisol, and, to a lesser degree, the glucose and insulin response to glucose were lowered by morphine anaesthesia. From the first to the fifth days after operation no differences between the two groups could be demonstrated in any parameter. Cumulative nitrogen balance was similar in the two groups. It is concluded that morphine in large doses administered before skin incision inhibits the initial endocrine-metabolic response to open-heart surgery, but that the effect is short-lasting and without effect on overall postoperative protein catabolism.

Plasma cyclic AMP in manic-depressive illness

The postulated disturbance of cyclic AMP (cAMP) in manic-depressive illness was investigated by using plasma as the biological material. Cyclic AMP was measured by a protein-binding assay, which was found very satisfactory for the purpose of this study. In the drug-free state, depressed patients (n = 28) had significantly lower and manic patients (n = 9) significantly higher plasma concentrations of cAMP than controls. Unmedicated manic-depressive subjects had normal cAMP levels during normothymic phases (n = 7). Cyclic AMP was reduced by neuroleptics in mania and elevated by tricyclics in depression. Lithium exerted a normalizing effect on cAMP in both phases of the illness. It is concluded that manic-depressive illness is associated with a disturbance in the cAMP system. The use of plasma rather than urine for the investigation of the state of cAMP in psychiatric disorders is advocated.

Inhibition of plasma cyclic AMP, glucose and cortisol response to surgery by epidural analgesia

Cyclic AMP, glucose and cortisol in plasma were measured in three groups of patients undergoing hysterectomy. The operations were performed under general anaesthesia, under general anaesthesia combined with epidural analgesia and under epidural analgesia alone. Surgery elicited a significant rise in plasma cyclic AMP, glucose and cortisol when performed under general anaesthesia alone. Epidural analgesia extending from T4-6 to S5 combined with general anaesthesia abolished the rise in cyclic AMP and reduced the increase in glucose and cortisol and epidural analgesia alone extending from T4 to S5 blocked the rise in glucose and cortisol as well as that in cyclic AMP. The results support the theory that afferent nerve impulses from the area of trauma are of major importance for the catabolic state induced by surgical procedures and indicate that anaesthetic management which includes blockade of afferent nerve impulses which includes blockade of afferent nerve impulses from the area of trauma can be reduce the catabolic response to surgery. These observations could be of value in the operative management of patients with diabetes mellitus and possibly in other groups by patients with a high surgical morbidity.