The endocrine response to trauma

Blunt Adrenal Injury is Not Associated With Worse Outcomes in Adult Trauma Patients

INTRODUCTION

Blunt adrenal injury is rare. Given production of hormones including catecholamines, adrenal injury may lead to worse outcomes. However, there is a paucity of literature on this topic. As such, we compared blunt trauma patients (BTPs) with and without adrenal injuries, hypothesizing similar mortality and complications between cohorts.

METHODS

The 2017-2019 Trauma Quality Improvement Program database was queried for adult (≥18-year-old) BTPs. Patients with penetrating trauma, traumatic brain injury, severe thoracic injury, or who were transferred from another hospital were excluded. Patients with adrenal injury were compared to those without using a 1:2 propensity score model. Matched variables included patient age, comorbidities, vitals on admission and concomitant injuries (i.e., liver, spleen, kidney, pancreas, and hollow viscus). Univariable logistic regression was then performed for associated risk of mortality.

RESULTS

2287 (0.2%) BTPs had an adrenal injury, with 1470 patients with adrenal injury matched to 2940 without adrenal injury. The rate of all complications including sepsis (0.1% versus 0.0%) was similar between cohorts (all P > 0.05). Patients with adrenal injury had a lower rate of mortality (0.1% versus 0.6%, P = 0.035) but increased length of stay (4 [3-6] versus 3 [2-5] days, P = 0.002). However, there was no difference in associated risk of mortality for patients with and without adrenal injury (odds ratio = 0.234; confidence interval = 0.54-1.015; P = 0.052).

CONCLUSIONS

Blunt adrenal injury occurred in <1% of patients. After propensity matching, there was a similar associated rate of complications but longer hospital length of stay for patients with adrenal injury. Adrenal injury was not associated with an increased risk of mortality.

Prediction of Recovery From Severe Hemorrhagic Shock Using Logistic Regression

This paper implements logistic regression models (LRMs) and feature selection for creating a predictive model for recovery form hemorrhagic shock (HS) with resuscitation using blood in the multiple experimental rat animal protocols. A total of 61 animals were studied across multiple HS experiments, which encompassed two different HS protocols and two resuscitation protocols using blood stored for short periods using five different techniques. Twenty-seven different systemic hemodynamics, cardiac function, and blood gas parameters were measured in each experiment, of which feature selection deemed only 25% of the them as relevant. The reduced feature set was used to train a final logistic regression model. A final test set accuracy is 84% compared to 74% for a baseline classifier using only MAP and HR measurements. Receiver operating characteristics (ROC) curve analysis and Cohens kappa statistics were also used as measures of performance, with the final reduced model outperforming the model, including all parameters. Our results suggest that LRMs trained with a combination of systemic hemodynamics, cardiac function, and blood gas parameters measured at multiple timepoints during HS can successfully classify HS recovery groups. Our results show the predictive ability of traditional and novel hemodynamic and cardiac function features and their combinations, many of which had not previously been taken into consideration, for monitoring HS. Furthermore, we have devised an effective methodology for feature selection and shown ways in which the performance of such predictive models should be assessed in future studies.

The relationship of plasma glucagon to the hyperglycaemia and hyperinsulinaemia of surgical operation

In a controlled metabolic study of 42patients undergoing abdominal surgery a significant increase in basal values of immunoreactive glucagon (IRG) was found 24 hours postoperatively. No correlation between the onset and duration of hyperglycaemia and the increase of IRG was observed. No increase in immunoreactive insulin (IRZ) was seen during operation, but there was a rise 24 hours postoperatively.

The infusion of arginine was accompanied by a rise in IRG both pre- and postoperatively, but despite the high values obtained there was no accompanying further increase in basal plasma glucose in the postoperative situation. The pre- and postoperative IRI responses were similar. Our evidence suggests that glucagon is not a primary mediator of the stress response, or of the hyperglycaemia of surgical operation in these patients.

Simulated postaggression metabolism in healthy subjects: metabolic changes and insulin resistance

Postaggression metabolism (PAM) is difficult to study in critically ill patients. The objective of this study was to simulate PAM in healthy subjects to quantify insulin sensitivity under these conditions. Six healthy men (age, 24 +/- 1 years; body mass index, 22.0 +/- 0.7 kg/m2 [mean +/- SE]) received an intravenous (i.v.) infusion of insulin-counteracting hormones (epinephrine 100 ng/kg/min, glucagon 16 ng/kg/min, hydrocortisone 5 microg/kg/min, and growth hormone [GH]-releasing hormone 50 microg/h) for 4 hours in addition to glucose (270 mg/kg/h). Control experiments used glucose only. In additional experiments, insulin sensitivity was measured by a two-step hyperinsulinemic glucose clamp with and without concomitant hormone infusion (insulin infusion rate, 2.5 and 5.0 mU/kg/min for hormone infusion or 1.0 and 2.5 mU/kg/min for control experiments). Plasma stress hormones reached levels comparable to severe PAM (epinephrine, 1,085 +/- 89 pg/mL; glucagon, 1,100 +/- 114 pg/mL; cortisone, 1,004 +/- 32 ng/mL; and GH, 20.6 +/- 6.1 pg/mL) in the hormone infusion experiment. This resulted in hyperglycemia and hyperinsulinemia (steady-state blood glucose, 19.7 +/- 0.4 mmol/L; serum insulin, 352 +/-8 pmol/L) in comparison to the control experiments with glucose infusion only (maximal blood glucose 7.2 +/- 0.8 mmol/L; serum insulin, 110 +/- 16 pmol/L). The insulin sensitivity index (S(I)) was 88% +/- 6% lower during hormone infusion (0.6 +/- 0.4 mL/min/m2/microU/min) compared with the control experiments (4.5 +/- 1.3 mL/min/m2/microU/min). Infusion of insulin-counteracting hormones at high doses allows simulation of the changes in carbohydrate metabolism observed in PAM in healthy subjects. The observed profound decrease in insulin sensitivity explains the hyperglycemia observed in nondiabetic critically ill patients. With this experimental setup, standardized investigations of therapeutic interventions in PAM should be possible.

Surgical stress inhibits the growth of fibroblasts through the elevation of plasma catecholamine and cortisol concentrations

To investigate the influence of surgical stress on fibroblast proliferation, serum samples were collected from 12 patients within 1 week after they had undergone gastrointestinal surgery, and the effect of these samples on the growth of fibroblasts from neonatal mice were evaluated by an in vitro assay. In addition, the course of the postoperative plasma levels of the stress-induced hormones, adrenaline, noradrenaline, and cortisol, and the direct effects of these substances on the proliferation of fibroblasts, were also analyzed. The sera collected from patients on the 1st, 3rd, and 7th postoperative day had a significant antiproliferative effect on the growth of fibroblasts. The evaluation of the levels of plasma catecholamines (adrenaline and noradrenaline) and cortisol revealed elevated postoperative concentrations of these substances in three patients, and the peaks were seen on the 1st or 3rd postoperative day. Furthermore, the growth of cultured fibroblasts was inhibited when each of these substances was added to the medium at a concentration comparable to the level found in the postoperative sera. These results suggest that adrenaline, noradrenaline, and cortisol may thus be among the circulating fibroblast growth inhibitors in postoperative patients and that surgical stress affects the formation of granulation in an inhibitory manner through the elevation of these stress-induced substances.

Impact of surgery on nitric oxide in rats: evidence for activation of inducible nitric oxide synthase

We investigated the effect of euvolemic surgical preparation, on chemical indices of activity of the nitric oxide (NO) system, in anesthetized, acutely prepared rats. The urinary excretion of NO2+NO3 (UNOXV) and cGMP (UcGMPV) increased progressively during the experiment. Pretreatment with aminoguanidine or dexamethasone, inhibitors of inducible NO synthase (iNOS), prevented the increase in UNOXV and UcGMPV but had no impact on mean arterial pressure (BP), renal vascular resistance (RVR) or GFR. Since these variables did not change in the conscious rat, the increased UNOXV results from some aspect of the acute surgical preparation. When acutely prepared rats received L-NAME, a non-specific NOS inhibitor, BP and RVR increased but paradoxical increases in UNOXV and UcGMPV were also seen. Nonselective NOS inhibition (+L-NAME) was fatal in 50% of acutely prepared rats, causing cardiac contracture. The same dose of L-NAME produced no deaths in either conscious chronically catheterized rats or in acutely prepared rats, previously subjected to sterile surgery and acute L-NAME in the conscious state. These data indicate that acute, nonsterile surgery induces expression of iNOS, but that the additional NO generated has no obvious cardiovascular/renal actions. Acute UNOXV and UcGMPV do not predict total NO production, or "hemodynamically active" NO. Generalized NO inhibition in rats acutely stressed by surgery/anesthesia can be fatal.

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.

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.

Sternotomy infection: poor prediction by acute phase response and delayed hypersensitivity

Two hundred twenty-one consecutive adult cardiac surgical patients were examined prospectively for nutritional protein state, acute phase protein response, and delayed hypersensitivity reaction in an attempt to identify patients at high risk for the development of sternal wound infection, which occurred in 6 patients (2.7%). There was no significant correlation between preoperative nutritional protein concentrations (retinol-binding protein, prealbumin, and transferrin) and acute phase protein levels (C-reactive protein, alpha 1-acid glycoprotein, and complements B and C3), nor a statistically significant relationship between nutritional state or acute phase protein response and the development of sternal infection. Preoperative complement C3 levels were elevated, however, in 80.0% of those in whom sternal infections developed compared with 30.6% of those with well-healed wounds. Similarly, postoperative concentrations of alpha 1-acid glycoprotein were elevated in 80.0% of those in whom sternal infections developed compared with 28.6% of those with well-healed wounds. There was no correlation between delayed hypersensitivity and the risk of sternal infection, nor between preoperative nutritional protein and acute phase protein values. Seventy-three percent of patients were anergic on postoperative day 2. Stepwise logistic regression showed that age, body weight, preoperative intensive care unit stay, repeat median sternotomy, internal mammary artery grafting, postoperative hemorrhage, and postoperative cardiac arrest correlated with the development of sternal infection, whereas transfusion requirement, reexploration for bleeding, and the operation performed did not. We conclude that routine delayed hypersensitivity testing is of no value in predicting high-risk cardiac surgical patients when the anergy battery is placed on the preoperative day. Although statistically insignificant, possibly due to the small number of patients in whom sternal infection developed in this study (type II error), a larger study might find preoperative complement C3 and post-operative alpha 1-acid glycoprotein levels to be predictive of patients at risk for the development of sternal wound infection. The final logistic model for the predicted risk 2%) of sternal wound infection is: PREDSWC = exp(EQ)/1 + exp(EQ) where EQ = (0.38 x age) + (0.24 x weight) + (5.42 x preop ICU) + (4.39 x redo) + (7.14 x IMA) + (4.49 x hemorrhage) + (8.81 x arrest) - 62.72, and where preop ICU, redo, hemorrhage, and arrest are defined as yes (1) or no (0), IMA-is defined as 0, 1, or 2, age is in years, and weight is in kilograms.

Effect of halothane anaesthesia on salivary elimination of paracetamol

The effect of halothane anaesthesia on paracetamol elimination was studied in 6 male patients undergoing short surgical procedures. Seven males operated on for the same indications under epidural anaesthesia served as the control group. Paracetamol concentration in saliva was measured at intervals on the day before and after surgery. Paracetamol t1/2 significantly decreased from 2.1 to 0.96 h and clearance rate (CL) significantly increased from 8.7 to 17.0 ml min-1 kg-1, when compared with the preoperative values. The control group also showed a significant but smaller alteration in the parameters. The results suggest that halothane anaesthesia per se may enhance the hepatic metabolism of paracetamol.

Evidence against the hypothesis that prostaglandins are the vasodepressor agents of pregnancy. Serial studies in chronically instrumented, conscious rats

Renal hemodynamics increase dramatically during pregnancy, and pressor responsiveness to exogenous administration of vasoconstrictors is attenuated. We investigated whether or not vasodilatory prostaglandins mediate these phenomena. Trained, chronically instrumented, conscious pregnant rats were used. Control values of glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were elevated at midgestation (P less than 0.01 and P = 0.05 from prepregnant means, respectively), and effective renal vascular resistance was decreased (P = 0.05). Indomethacin (4.5-6.5 mg/kg body weight [BW]) failed to decrease renal hemodynamics at this stage of pregnancy; in fact, it raised GFR somewhat further (P less than 0.05). Systemic pressor responsiveness to bolus administration of norepinephrine and angiotensin II (AII) was significantly attenuated by at least gestational day 20. Neither indomethacin (7 mg/kg BW) or meclofenamate (6 mg/kg BW) affected the refractory response. The renal vasculature was also relatively unresponsive to an intravenous infusion of AII (5 ng X kg-1 X min-1) during late gestation (day 19); in particular, the fall in ERPF in response to AII (16 +/- 3%) was markedly less than that observed in the prepregnant condition (34 +/- 3%; P less than 0.05). Indomethacin (6 mg/kg BW) failed to restore this blunted response, and further attenuation was evident, despite the presence of the inhibitor (gestational day 21). We conclude that vasodilatory prostaglandins do not appear to mediate the rise in renal hemodynamics, and the attenuation of the systemic and renal pressor responsiveness observed during pregnancy, insofar as these phenomena were unaffected by acute cyclooxygenase inhibition in unstressed, conscious rats.

Determination of intraoperative plasma catecholamine concentrations using liquid chromatography with electrochemical detection

Liquid chromatography with electrochemical detection was used for the determination of norepinephrine and epinephrine in human plasma samples obtained prior to, after, and six times during the course of spinal fusion surgery for the correction of scoliosis. The catecholamines were extracted from plasma by alumina adsorption and chromatographed isocratically using a reversed-phase, ion-pairing system. Data obtained are compared to those obtained intraoperatively by other authors using a radioenzymatic method, and the mechanism of sympathetic activation during surgery is discussed. Preliminary data using 3-micron particle size columns and dual-parallel electrochemical detection are presented.

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.

Effect of short surgical procedures on salivary paracetamol elimination

The effect of short surgical procedures on paracetamol elimination was studied in seven male patients undergoing surgery with epidural anaesthesia. Five healthy volunteers who did not undergo surgery served as a control group. Paracetamol concentration was measured in saliva at various intervals 1 day before and after surgery. Paracetamol half-life (t1/2,z) decreased and metabolic clearance rate (CL) increased after surgery as compared to preoperative values. The results suggest that surgical stress may enhance the hepatic metabolism of paracetamol.

Endocrine and protein response to elective surgery: Effect of nursing at two different environmental temperatures

Twenty male patients undergoing elective abdominal surgery were studied on one control day pre-operatively and for the first 4 days postoperatively at an environmental temperature of either 20 degrees C or 28 degrees C. Glucose, insulin, growth hormone and urinary catecholamine levels all rose significantly on the first postoperative day returning to within normal limits by day 4. Urine nitrogen excretion also increased significantly postoperatively in both groups. Environmental temperature did not influence these responses. Concentrations of C-reactive protein and a1-antichymotrypsin increased significantly on the first postoperative day and were returning to normal by day 4 while concentrations of haptoglobin, a1-antitrypsin and a1-acid glycoprotein, which also showed a significant increase, remained elevated at the end of the study. Concentrations of albumin, transferrin, a2-macroglobulin, prealbumin and retinol binding protein all decreased significantly following operation. Elevated environmental temperature did not affect the protein response to surgery. Urine cortisol and 17-hydroxycorticosteroid excretion rose significantly postoperatively and remained elevated throughout the study. Patients nursed at 28 degrees C showed significantly lower postoperative excretion of both hormones than patients nursed at 20 degrees C.

Management of the diabetic surgical patient. A systematic but flexible plan is the key

Diabetes control is especially important when the patient is undergoing surgery, as the trauma can result in major metabolic changes. Complications of diabetes must be assessed preoperatively, since they themselves can lead to the need for surgery or can predispose to increased surgical or anesthetic risk. The preoperative blood glucose status of diabetics can be assessed by use of standard laboratory methods, self monitoring devices, urine glucose testing, or measurement of glycohemoglobin level. Blood glucose control can be maximized by designation of one physician on the health care team to be in charge of fluid, electrolyte, and insulin administration on perioperative days. This physician should follow a definite protocol of subcutaneous insulin administration guided by appropriate monitoring of blood glucose response. In special cases, such as surgery in the pregnant diabetic, a more complex scheme of management using low-dose insulin infusion may be required. Coexistence of another endocrine disease with diabetes should be recognized, since it may lead to otherwise unexpected changes in insulin requirements. A systematic and comprehensive yet flexible approach to the treatment of diabetes before, during, and after surgery puts a successful outcome well within the reach of the modern clinician.

Effect of a mixed meal on hepatic lactate and gluconeogenic precursor metabolism in dogs

The present experiments were undertaken to assess lactate and gluconeogenic precursor metabolism in the 30 h following consumption of a mixed meal by the overnight-fasted, conscious dog. The arterial glucose level rose by a maximum of 13 mg/dl 4 h after the meal and had returned to control levels by 12 h. Hepatic glucose production was suppressed for 12 h after feeding, but net hepatic glucose uptake did not occur. The arterial lactate level rose from 0.55 +/- 0.10 to 1.28 +/- 0.14 mM within 1 h of feeding and remained elevated for 12 h. Net hepatic lactate production, measured with an A-V difference technique, rose from 3.5 +/- 2.8 to 19.4 +/- 3.1 mumol X kg-1 X min-1 h after the meal and declined slowly over the next 22 h. The liver then began to consume lactate so that at 30 h net hepatic uptake was 5.7 +/- 0.5 mumol X kg-1 X min-1. The total hepatic uptake of the gluconeogenic amino acids (alanine, glycine, serine, threonine) increased from 5.3 +/- 0.8 to 11.5 +/- 2.5 mumol X kg-1 X min-1 at 1 h and remained elevated for 4 h. The arterial alanine level rose from 0.36 +/- 0.03 to 0.51 +/- 0.04 mM at 2 h and remained elevated for 18 h. Insulin increased from 11 +/- 2 microU/ml to a maximum of 44 +/- 5 4 h after the meal, and the glucagon level rose from 59 +/- 8 pg/ml to a maximum of 150 +/- 22 1 h after feeding.(ABSTRACT TRUNCATED AT 250 WORDS)

Renal hemodynamics during pregnancy in chronically catheterized, conscious rats

Two types of experiments were performed, cross-sectional and longitudinal. In the cross-sectional studies, rats were mated, later prepared surgically, and then 5 or more days after surgery, each examined twice during days 11 to 15 or days 18 to 20 of gestation. Nonpregnant rats matched for age and prepregnant weight served as controls. In the longitudinal studies, rats were catheterized and, starting 6 days later, examined twice; then the same rats were mated and each was studied on days 5, 8, 12, 16, and 20 of gestation, as well as on day 5 postpartum. In the cross-sectional studies, glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were elevated by approximately 26% and 20%, respectively, above nonpregnant controls at 11 to 15 days of gestation (GFR, 2739 +/- 94 vs. 2181 +/- 134 microliters . min-1, P less than 0.005; ERPF, 9367 +/- 295 vs. 7785 +/- 422 microliters . min-1, P less than 0.01). By 18 to 20 days of gestation, GFR and ERPF had returned to levels that were not significantly different from nonpregnant values. The longitudinal studies confirmed these findings in every respect and further revealed that GFR and ERPF were elevated above nonpregnant values as early as day 5 of gestation (P less than 0.005). Thereafter, they rose to peak values, at 12 and 16 days of gestation, of 3122 +/- 144 and 10,584 +/- 541 microliters . min-1, and then returned to nonpregnant levels by day 20 of gestation.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma cortisol levels. A comparison between sick patients and volunteers given intravenous cortisol

The plasma cortisol levels of 30 very sick patients were measured to determine whether evidence of suprarenal failure could be found. Volunteers were given 100 mg hydrocortisone intravenously and their plasma cortisol levels were measured. The results suggest that suprarenal failure is a very uncommon occurrence. The results obtained from the volunteers imply that relatively small amounts of hydrocortisone given intravenously cause a marked elevation of plasma cortisol levels.

Metabolism of phenazone in man after hydrocortisone administration

The influence of a high plasma concentration of hydrocortisone on the metabolism of phenazone in humans has been studied. Two series of experiments were carried out, Group A to demonstrate any enzyme-inducing effect of hydrocortisone, and Group B to study the immediate effect of hydrocortisone on the metabolism of phenazone. 9 subjects (Group A) received a total 250--400 mg hydrocortisone i.m. twice daily for three days and the 24-hour elimination of phenazone was studied before and afterwards. In a further 5 subjects (Group B) the elimination of phenazone was examined during administration of hydrocortisone of placebo. The elimination rate and the apparent volume of distribution of phenazone remained unchanged under both experimental conditions.

Urinary cyclic AMP and post-traumatic acute renal failure

Consecutive daily urinary excretion of cyclic AMP has been investigated in 16 patients with severe trauma or illness, five of whom developed acute renal failure (ARF). Fluctuations in the nucleotide excretion exceeded the range found in 20 healthy volunteers (1.26-14.74, mean 7.13+/-1.18 vs. 2.04-10.10, mean 5.07+/-2.21 micronmol/24 h). This resulted in a 41% increase of cAMP excretion in the group with normal renal function (P less than 0.003) with the highest individual increase of 87%. The excretion usually reached its peak by 24 h after trauma and its lowest value by the third day, (first day vs. third day; 7.82+/-4.23 vs. 3.96+/-2.58 micronmol/24 h, P less than 0.05 for a group of 11 patients), while creatinine clearance remained normal. In four patients with severe ARF, the mean urine volume was above control value but the cAMP excretion was reduced to 3.9 to 14.4% and in one patient with a mild ARF to 60.6%. Creatinine excretion of the group was less reduced than that of cAMP (41.2% vs. 19.6%, resp.). cAMP excretion declined proportionally with diminishing creatinine clearance. In the category of 33-65 ml/min it decreased by 33.4% to 3.39 micronmol+/-1.16 micronmol/24 h. cAMP/creatinine ratio proved to be a less sensitive indicator than cAMP/24 h. Daily output of cAMP and creatinine correlated highly with diuresis in ARF patients, controls (always P less than 0.001) and less in patients with normal renal function (P less than 0.02). Urinary cAMP appears to be a very sensitive and early indicator of the onset of ARF and subsequent recovery. This warrants its further study.

The site of synthesis and functions of acute phase plasma proteins: close relationship with the reticulo-endothelial system

The evidence that the acute phase glycoproteins of plasma are synthesized by the liver parenchymal cells is critically examined, and is found to be inconclusive. Some evidence is cited which favors the reticulo-endothelial system (RES) in general, and Kupffer cells in particular, as the site of synthesis of these proteins: 1. The entire RES contains non-glycogenic periodic acid Schiff-positive substances. 2. The diseases which affect glycoprotein levels are also known to affect the function of the RES. 3. When the animal is subjected to stress, the RES function is initially depressed and then stimulated. A similar biphasic behavior is shown by plasma glycoprotein levels. 4. Adrenal cortico-steriods are the major regulators of the RES function and of the synthesis of acute phase proteins. Moreover, both are stimulated at low concentrations, and depressed at high concentrations of the hormone. Some of the glycoproteins of the acute phase (prothrombin, the third component of complement, haptoglobin, transferrin and ceruloplasmin) have defense-related functions. The others seem to participate in phenomena like detoxification, promotion of phagocytosis, wound healing, prevention of tissue injury by lysosomal enzymes, prevention of trauma and recovery from inflammation. It is proposed that the acute phase proteins, together with antibodies, form major components of the definse system, and the RES attempts to deal with injury by mobilization of increased amounts of these substances.

Glycogen phosphorylase, glucose output and vasoconstriction in the perfused rat liver. Concentration-dependence of actions of adrenaline, vasopressin and angiotensin II

1. Glycogen phosphorylase (a form, in rapidly freeze-clamped samples) and glucose release were measured in the perfused liver, in response to a range of concentrations of adrenaline, [8-arginine]vasopressin (anti-diuretic hormone) and angiotensin II. 2. All three hormones increased phosphorylase a activity by about 10 mumol/min per g of fresh liver, which was more than sufficient to explain concomitant glucose release (1-2mumol/min per g). 3. Minimally effective concentrations which activated phosphorylase were: adrenaline, 10nM (2ng/ml); vasopressin, 40pM (40pg/ml, 15 muunits/ml); angiotensin II, 60pM (60pg/ml). 4. Glycogen synthase activity was inhibited by adrenaline and vasopressin but not significantly by angiotensin II. 5. Vasoconstriction observed with adrenaline and angiotensin II (but not vasopressin) might explain part of the activation of phosphorylase, since equivalent vasoconstriction (in separate perfusions) activated phosphorylase, did not stimulate glucose output or inhibit synthase. 6. The potency of these effects suggests that all three hormones can stimulate hepatic glycogen degradation in vivo (by direct hepatic action). It is proposed that hormones, and ischaemia, stimulate glycogen degradation to provide glucose phosphates for disposal within the liver cell, as well as for release as free gluose.

Effects of burn injury on insulin secretion and on sensitivity to insulin in the rat in vivo

Both insulin resistance and impairment of insulin secretion are know to occur in man after injury. The relative importance of these effects was studied in rats 2 h after a non-lethal 20 percent dorsal scald. No impairment of insulin secretion was found after this injury. Concentrations of both blood glucose and plasma insulin were elevated in scalded rats. Scalded rats responded to intravenous glucose injection (1-0 g/kg) with a further rise in plasma insulin concentration, which remained normal for the prevailing blood glucose concentration. However, marked impairment of glucose tolerance was observed, indicating the presence of insulin resistance. After intravenous insulin injection (1-0 U/kg) the initial rate coefficient for fall of blood glucose concentration was significantly lower (p less than 0-02) in scalded (mean 3-9 percent min.(-1) than in control rats (mean 6-3 percent min.(-1). The minimum in blood glucose concentration after insulin injection was reached at 10 min. in control rats, but not until 60 min. after injection in scalded rats. This difference was due to a delay in compensation for the hypoglycaemia in the scalded rats, since the rate of disappearance of insulin measured by injection of a tracer of 125I-labelled bovine insulin was not decreased after this injury. It was concluded that the impairment of glucose utilization in scalded rats (Heath and Corney, 1973) is due to decreased sensitivity to insulin rather than to suppression of insulin release.

Effects of abdominal surgery under general anaesthesia and of postoperative analgesic therapy on splanchnic exchange of some blood borne energy metabolites

Sixteen patients with gallbladder disease, but otherwise healthy, were studied in connection with cholecystectomy. For postoperative analgesia, seven patients were given a posterior splanchnic blockade, 30 ml of 0.5% plain lidocaine, and nine patients were given fentanyl intramuscularly in a dose of 3.5 mug/kg b.w. Immediately after the operation and before analgesia, the arterial blood concentrations of glucose, lactate, glycerol, 3-hydroxybutyrate, and free fatty acids increased significantly. The splanchnic exchange of these metabolites was also significantly increased, except for glucose, the splanchnic release of which was significantly reduced. Induction of analgesia, both methods, was followed by a rapid significant decrease of the arterial blood concentration of glycerol, which tended to rise later when the analgesia disappeared. The arterial blood concentration of glucose and lactate showed a tendency to decrease slowly following both kinds of analgesia, while the arterial blood concentration of 3-hydroxybutyrate remained stable. The splanchnic release of glucose was significantly reduced after administration of fentanyl, while it increased significantly following splanchnic blockade, the splanchnic glucose release being correlated to arterial blood pH. The splanchnic release of 3-hydroxybutyrate was significantly reduced during maximal analgesia in both groups. The splanchnic uptakes of glycerol and free fatty acids were correlated to their splanchnic inflows.

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

The response of plasma cortisol and cyclic AMP concentrations to surgical trauma was examined in 7 general surgical patients. Five patients made uncomplicated recoveries and showed peak cortisol levels at 6 hours postoperatively, returning to normal by 24 hours. On patient developed postoperative pneumonia and the plasma cortisol remained elevated up to 48 hours, and the final patient showed no cortisol response at all. The plasma cyclic AMP concentrations showed a consistent rise during the operation itself, which was statistically significant when compared with preoperative levels (P less than 0.0125). Concentrations had fallen to normal by 6 hours in all the cases, except in the patient who developed pneumonia, where the plasma cyclic AMP also showed a prolonged elevation. The significance of these findings requires further elucidation, but the temporal relationship of the cyclic AMP and cortisol peaks would support the hypothesis that cyclic AMP may play a part in the mediation of ACTH release following surgical trauma.

Plasma catecholamines in severely injured patients: a prospective study on 45 patients with multiple injuries

Plasma catecholamine levels were studied in 45 severely injured patients for 8 days after the trauma. Sixteen of the patients were classified as critically injured and 29 as seriously injured. The total plasma catecholamine values of the whole group immediately after the injury were almost twice as high as the eighth day reference values and remained significantly higher than these values for 6 hours after the trauma. On admission both the plasma adrenaline and noradrenaline levels were elevated. The plasma adrenaline levels on admission correlated with the blood volume replacement which was required within the first 6 hours. The plasma noradrenaline levels in the critically injured group were significantly higher throughout the observation period than in the seriously injured group. A corresponding difference was observed in the plasma adrenaline concentrations only during the first 12 hours. The results showed that strong stimulation of the sympathetic nervous system occurs in severely injured patients. Factors stimulating the sympathetic nervous system apparently included hypovolaemia, tissue hypoxia, acidosis and the pain produced by the trauma and therapeutic measures.

Stimulation by vasopressin of glycogen breakdown and gluconeogenesis in the perfused rat liver

1. Vasopressin (anti-diuretic hormone, [8-arginine]vasopressin) stimulated the breakdown of glycogen in perfused livers of fed rats, at concentrations (50-600muunits/ml) that have been reported in the blood of intact rats, especially during acute haemorrhagic shock. 2. In perfused livers from starved rats, vasopressin (30-150muunits/ml) stimulated gluconeogenesis from a mixture of lactate, pyruvate and glycerol. 3. Vasopressin prevented accumulation of liver glycogen in the perfused liver of starved rats, or in starved intact rats. 4. The action of vasopressin on hepatic carbohydrate metabolism thus resembles that of glucagon; the minimum effective circulating concentrations of these hormones are of the same order (100pg/ml). 5. The stimulation of hepatic glucose output by vasopressin is discussed in connexion with the release of glucose and water from the liver.