Incidence of clinically symptomatic pneumothorax in ultrasound-guided infraclavicular and supraclavicular brachial plexus block.

The use of periclavicular brachial plexus block as regional anaesthesia for surgical procedures on the upper extremity is common. However, the proximity of the pleura results in a risk of pneumothorax. Without ultrasound monitoring, the pneumothorax risk has been reported to be as high as 6.1%. We conducted a prospective, observational study to examine the risk of pneumothorax in 6366 ultrasound-guided periclavicular plexus blocks. All patients with a clinically manifest and radiologically confirmed pneumothorax were analysed. Clinically symptomatic pneumothorax occurred in four patients (0.06%; 95% CI 0.001-0.124), in three of them after a two-day latency period. Ultrasound guidance does therefore appear to reduce the risk of pneumothorax. Although all of the anaesthesiologists involved in the complications had previously performed fewer than 20 blocks, we are not able to confirm that a block experience ≤ 20 is a significant risk factor. Faulty image-setting, inability to obtain a view of the needle tip and inadequate supervision are likely to be important risk factors.

Effect of combining nicotinamide as a PARS-inhibitor with selective iNOS blockade during porcine endotoxemia.

OBJECTIVE: To investigate the effects of combined selective inducible nitric oxide synthase (iNOS) inhibition using 1400 W with nicotinamide (NAD) as a PARS-inhibitor on hepato-splanchnic hemodynamics, O(2) kinetics, and energy metabolism during hyperdynamic porcine endotoxemia. DESIGN: Prospective, randomized, controlled, interventional experiment. SETTING: Animal research laboratory. SUBJECTS: Seventeen domestic pigs. INTERVENTIONS: After 12 h of continuous i.v. endotoxin (LPS) infusion 17 pigs received either no drug (CON, n=9) or 1400 W, titrated to maintain mean arterial pressure (MAP) at pre-endotoxin level, plus 10 mg.kg.h NAD ( n=8;). Measurements were obtained before, 12 h, 18 h, and 24 h after starting LPS infusion. MEASUREMENTS AND RESULTS: In addition to systemic and pulmonary hemodynamics and gas exchange, we measured hepatic arterial and portal venous blood flow, liver and portal venous drained viscera O(2) exchange, ileal mucosal-arterial PCO(2) gap, and portal as well as hepatic venous lactate/pyruvate ratios. Expired NO and plasma nitrate levels were assessed as a parameter of NO production. Without affecting cardiac output, therapy maintained MAP and blunted the LPS-induced rise in expired NO levels, attenuated the progressive fall in liver lactate clearance, and blunted the impairment of hepato-splanchnic redox state. The rise of ileal mucosal-arterial PCO(2) gap was not influenced. CONCLUSIONS: Combining selective iNOS inhibition with NAD as a PARS blocker may prevent circulatory failure and attenuate the detrimental consequences of LPS in intestinal and hepatocellular energy metabolism. Given the potential hepatotoxicity of high-dose NAD treatment, more potent PARS blockers with higher selectivity might further enhance the benefit of this therapeutic approach.

Hepatic oxygen exchange and energy metabolism in hyperdynamic porcine endotoxemia: effects of the combined thromboxane receptor antagonist and synthase inhibitor DTTX30.

OBJECTIVE: We compared the effects of thromboxane receptor antagonist and synthase inhibitor DTTX30 on systemic and liver blood flow, oxygen (O2) exchange and energy metabolism during 24 h of hyperdynamic endotoxemia with untreated endotoxemia. DESIGN: Prospective, randomized, experimental study with repeated measures. SETTING: Investigational animal laboratory. SUBJECTS: Twenty-seven domestic pigs: 16 during endotoxemia with volume resuscitation alone; 11 with endotoxemia, volume resuscitation and treatment with DTTX30. INTERVENTIONS: Continuous infusion of Escherichia coli lipopolysaccharide (LPS) for 24 h together with volume resuscitation. After 12 h of endotoxemia, DTTX30 was administered as a bolus of 0.12 mg kg-1 followed by 12 h continuous infusion of 0.29 mg kg-1 per h. MEASUREMENTS AND RESULTS: DTTX30 effectively counteracted the endotoxin-associated increase in TXB2 levels and increased 6-keto-PGF1 alpha with a significant shift of the thromboxane/prostacyclin ratio towards predominance of prostacyclin. DTTX30 prevented the significant progressive endotoxin-induced decrease of mean arterial pressure (MAP) below baseline while maintaining cardiac output (CO), and increased the fractional contribution of liver blood flow to CO without an effect on either hepatic O2 delivery or O2 uptake. The mean capillary hemoglobin O2 saturation (HbO2) on the liver surface and HbO2 frequency distributions remained unchanged as well. CONCLUSIONS: DTTX30 significantly attenuated the endotoxin-induced derangements of cellular energy metabolism as reflected by the diminished progressive decrease in hepatic lactate uptake rate and a blunted increase in hepatic venous lactate/pyruvate ratios. While endotoxin significantly increased the endogenous glucose production (EGP) rate, EGP returned towards baseline levels in the DTTX30-treated group. Thus, in our model DTTX30 resulted in hemodynamic stabilization concomitant with improved hepatic metabolic performance.

Effects of nicotinamide, an inhibitor of PARS activity, on gut and liver O2 exchange and energy metabolism during hyperdynamic porcine endotoxemia.

OBJECTIVE: To investigate the effects of nicotinamide (NIC), an inhibitor of poly(ADP-ribose) synthetase (PARS), on intestinal and liver perfusion, O2 kinetics, and energy metabolism over 24 h of hyperdynamic porcine endotoxemia. DESIGN: Prospective, randomized, controlled experimental study with repeated measures. SETTING: Animal laboratory in a university hospital. SUBJECTS: Sixteen pigs, divided into two groups: nine endotoxemic animals without therapy (CON); seven animals treated with NIC. INTERVENTIONS: Pigs were anesthetized, mechanically ventilated, and instrumented. Intravenous E. Coli LPS was continuously infused over 24 h concomitant with fluid resuscitation. After 12 h of endotoxemia continuous i.v. infusion of NIC (10 mg/kg per hour) was administered until the end of the experiment. MEASUREMENTS AND RESULTS: All animals developed hyperdynamic circulation with sustained increase in cardiac output and progressive fall in mean arterial pressure. NIC maintained blood pressure without affecting CO. Hepato-splanchnic macrocirculation was not modified by the treatment. Nevertheless, although NIC attenuated the progressive rise of ileal mucosal-arterial PCO2 gap, it failed to improve portal venous L/P ratio, a marker of the overall energy state of the portal venous drained viscera. Similarly, neither the increased hepatic venous L/P ratio nor the simultaneous drop in hepatic lactate uptake were influenced by NIC. CONCLUSIONS: Although NIC maintained hemodynamic stabilization during long-term endotoxemia, it was unable to improve LPS-induced deterioration of the hepato-splanchnic energy metabolism. More potent and selective PARS inhibitors are needed to elucidate the role of a PARS-dependent pathway in a clinically relevant models of sepsis.

Neonatal iron nutrition.

Preterm infants are prone to iron deficiency. Their total body iron content at birth is low and gets further depleted by clinical practices such as uncompensated phlebotomy losses and exogenous erythropoietin administration during the neonatal period. Early iron deficiency appears to adversely affect cognitive development in human infants. To maintain iron sufficiency and meet the iron demands of catch-up postnatal growth, iron supplementation is prudent in preterm infants. A dose of 2-4 mg/kg/day is recommended for preterm infants who are fed exclusively human milk. A dose of 6 mg/kg/day or more is needed with the use of exogenous erythropoietin or to correct preexisting iron deficiency. However, due to the poor antioxidant capabilities of preterm infants and the potential role of iron in several oxidant-related perinatal disorders, indiscriminate iron supplementation should be avoided.

Hepatic O2 exchange and liver energy metabolism in hyperdynamic porcine endotoxemia: effects of iloprost.

OBJECTIVE: To compare the effects of a 12 h continuous infusion of iloprost, a stable prostacyclin analogue, on hepatic blood flow (Qliv), O2 exchange, and energy metabolism during a 24 h hyperdynamic, porcine endotoxemia with volume resuscitation alone. DESIGN: Prospective, randomized, experimental study with repeated measures. SETTING: Investigational animal laboratory. SUBJECTS: Twenty-eight domestic pigs: 16 animals during endotoxemia with volume resuscitation alone (ETX), 12 with endotoxemia, volume resuscitation, and treatment with iloprost (ILO). INTERVENTIONS: Endotoxemia was initiated by continuous infusion of E. coli lipopolysaccharide. Animals were resuscitated with hetastarch, aimed at maintaining a MAP of > 60 mmHg. After 12 h of endotoxemia, iloprost was administered for 12 h in the treatment group, titrated to avoid pharmacologically induced hypotension (MAP < 60 mmHg). MEASUREMENTS AND RESULTS: Iloprost significantly increased Qliv, with no effect on hepatic O2 delivery. Mean capillary hemoglobin O2 saturation (HbScO2) on the liver surface, as well as HbScO2 frequency distributions--a measure of microcirculatory O2 availability--remained unchanged. Treatment with iloprost, however, significantly attenuated the endotoxin-induced derangements of cellular energy metabolism as reflected by the diminished progressive decrease in hepatic lactate uptake rate and a blunted increase in hepatic venous lactate/pyruvate ratios. While endotoxin significantly increased endogenous glucose production (EGP) rate, iloprost restored EGP to normal at the end of the experiment. CONCLUSIONS: Thus, in a clinically relevant model of human sepsis, iloprost did not produce potential adverse effects but rather ameliorated hepatic metabolic disturbances and, thereby, hepatic energy balance.

Xenon does not induce contracture in human malignant hyperthermia muscle.

Xenon has many characteristics of an ideal anaesthetic agent. It is not known whether xenon is a safe alternative to the potent inhalational anaesthetics in patients susceptible to malignant hyperthermia (MH). We investigated the effect of xenon, halothane and caffeine on muscle specimens of 31 individuals, referred to the MH Unit of the University of Ulm, and performed genetic epidemiology. Thirteen individuals were classified as MH susceptible and 18 as MH negative. Xenon 70% did not cause an increase in baseline tension of any MH-susceptible muscle specimen in contrast to halothane and caffeine. The evoked twitch response increased transiently in MH-susceptible and normal specimens indicating a mechanism independent of MH susceptibility. These results suggest that xenon, in concentrations up to 70% may be a safe anaesthetic for MH-susceptible patients.

[Effects of priming technique on onset profile of cisatracurium]. / Auswirkung der Priming-Technik auf die Anschlagszeit von Cisatracurium.

Compared to atracurium, cisatracurium releases less laudanosine and histamine, but it has a longer onset time. The primary objective of this study was a blinded, randomized comparison of intubation scores and onset times of a threefold ED 95 of cisatracurium using the priming technique with two priming substances cisatracurium itself and pancuronium. To test the effect of priming with cisatracurium or pancuronium on the onset of cisatracurium, 45 patients were anaesthetised with 0.15-0.25 mg/kg alfentanil, 0.25-0.3 mg/kg edomidate i.v. and O2/N2O, and were randomisely divided into one of three groups. After induction, 15 patients were primed with sodium chloride and thereafter received 0.15 mg/kg cisatracurium, 15 patients were primed with 0.01 mg/kg cisatracurium, another 15 patients were primed with 0.015 mg/kg pancuronium and the last two groups received 0.14 mg/kg cisatracurium three minutes later. Neuromuscular response was monitored by adductor pollicis electromyogram (EMG) by stimulating in a TOF pattern. Times for T1 reduction to 75%, 50%, 25% and 0% and T1 recovery to 25% were taken. Intubation was performed 120 seconds after the main relaxant dose and scored in four grades. The two priming groups showed a significantly faster onset of neuromuscular blockade than the control group (cisatracurium priming group: T1 = 0: 178.4 +/- 16.3 sec., pancuronium priming group 171.2 +/- 15.3 sec. vs. control group: T1 = 0: 205.5 +/- 18.9 sec.). Both primed groups showed no significantly better intubation scores, compared with the control group. Using the priming principle, cisatracurium will give good intubation scores 120 seconds after injection with a clinical duration profile comparable to an equipotent dose of atracurium.

Basic fibroblast growth factor reduces lactic acid-induced neuronal injury in rat hippocampal neurons.

OBJECTIVE: To evaluate the long-term effects of lactic acidosis and to examine a potential neuroprotective role of basic fibroblast growth factor (bFGF) on hippocampal neurons. DESIGN: Long-term observation in a cell-culture study. SETTING: University research laboratory. SUBJECTS: Adult, differentiated, primary rat hippocampal neurons. INTERVENTIONS: Neurons were exposed to medium acidified with 20 mM lactic acid, pH 6.2, for a 10-min period, and maintained untreated or in the presence of bFGF (500 pg/mL, 1 ng/mL, 10 ng/mL, 20 ng/mL) applied after exposure. MEASUREMENTS AND MAIN RESULTS: Viability was analyzed by a dye inclusion/enzyme activity test and morphology by phase contrast and immunofluorescence microscopy. [3H]Arachidonic acid (AA) release was measured by liquid scintillation spectrometry. All cultures appeared to be unchanged during the first days after exposure to lactic acidosis. Neurodegeneration became apparent within 3 days. Seven days after exposure, cell survival decreased to 60% in lactic acidosis-injured, untreated cultures. Morphologic damage appeared as a 50% reduction in axonal and 25% reduction in dendritic arborizations. AA release increased to four-fold enhanced levels relative to control values. bFGF (1, 20, and 10 ng/ mL) enhanced neuronal viability (p < .05), and 10 ng/mL bFGF induced a maximal increase in live cells to 80% of controls. Axonal arborizations increased to 50% and dendritic arborizations to 75% of controls after 10 ng/mL bFGF (p< .05). bFGF in a dose of 20 ng/ mL enhanced axonal branching to 40% and dendrites in number and branching to 50% of controls (p< .05). bFGF (500 pg/mL, and 1 and 10 ng/mL) decreased enhanced AA (p < .05), and 10 ng/mL bFGF maximally reduced increased AA to two-fold enhanced values relative to controls. CONCLUSIONS: In vulnerable neurons, exposure to moderate lactic acidosis induces a process of cell injury with long latency. bFGF applied postinjury reduces the delayed neurodegeneration and may have neuroprotective efficacy in new therapeutic strategies to ischemia-induced cerebral injury.

[Parenteral nutrition therapy. Energy and non-energy actions of carbohydrates and fats]. / Die parenterale Ernährungstherapie. Energetische und nicht-energetische Wirkungen von Kohlenhydraten und Fetten.

The object of this review is to demonstrate the non-nutritional importance of carbohydrates and fat as they represent the classic energy carriers in parenteral nutrition. Concerning the pathophysiological changes of organ metabolism and intermediary metabolism as well as the pharmacological function of this nutritive substrates it is necessary to adjust parenteral nutrition strategy to various clinical pictures. The major goals of parenteral applicated carbohydrates are to avoid hyperglycemia, to return the increased hepatic glucose production during trauma and sepsis back to normal, and to reduce protein catabolism. Realizing this goals the dosage of glucose infusion underlies close metabolic borders depending on the present disease. Because of favourable effects of hepatic glucose and protein metabolism, xylitol, a non-glucose polyol, represents an useful alternative energy source to glucose. The non-energetic nutrition therapy with fat consists of application of the essential fatty acids linoleic and alpha-linolenic acid and considers the immunmodulatory effects of various fatty acids as precursors in the eicosanoid metabolism. As demonstrated at the organ systems of liver and lung this pharmacological effects of any lipid infusion might influence specific organ functions.

Effects of basic fibroblast growth factor on hippocampal neurons after axonal injury.

OBJECTIVE: Axons of adult central nervous system neurons fail to regenerate after diffuse axonal injury in head trauma. Basic fibroblast growth factor (bFGF) has been reported to enhance neuritic extensions after neuronal injury in immature nerve cells. To investigate the effects of bFGF on adult neurons and axonal reoutgrowth, differentiated nerve cells were axonally transected and bFGF was applied. DESIGN: Cell culture study with primary rat hippocampal neurons. MATERIALS AND METHODS: After axotomy, hippocampal cultures were maintained untreated or in the presence of 0.5, 1, 10, or 20 ng/mL bFGF and evaluated over a 7-day period after injury. MEASUREMENTS AND MAIN RESULTS: Seven days after injury, axotomy decreased cell survival to 65%, increased [3H]arachidonic acid release 1.8-fold from prelabeled cells, and showed negligible effects on neuronal dendrites. bFGF reduced this neurodegeneration at all doses applied. bFGF at 10 ng/mL most efficiently increased live cells to 85% and decreased [3H]arachidonic acid release from prelabeled cells to control values (p < 0.01, vs. damaged cells). Furthermore, 10 ng/mL bFGF induced axonal branching and the longest axonal re-extensions from 60 +/- 8 to 377 +/- 10 microns 7 days after injury (p < 0.01, vs. damaged cells). CONCLUSIONS: bFGF increased cell survival and supported axonal re-elongations in adult hippocampal neurons in vitro when applied after axotomy. bFGF may play a role in new therapeutic concepts for the management of axonal injury after head trauma.

Shed mediastinal blood in 500 elective cardiac surgery patients: is there enough for retransfusion routinely?

OBJECTIVE: Since an increased use of several blood salvaging measures has contributed to a reduction in perioperative blood loss and the requirement for banked blood in recent years, the aim of this study was to establish current postoperative drainage losses in order to evaluate whether homologous retransfusion may be a useful measure to reduce autologous transfusion in elective cardiac surgery. DESIGN/SETTING: This prospective clinical investigation was performed at a University Intensive Care Unit during the first six hours following cardiac surgery. PATIENTS: 373 men and 127 women undergoing elective cardiac surgery were investigated. MEASURES: The amount of shed blood was measured four and six hours postoperatively. RESULTS: The average blood loss was higher in men than in women both in all operations as a whole (men, four hours: 223+/-73 ml, six hours 270+/-95 ml; women, four hours: 156+/-25 ml, six hours 195+/-22 ml), in valve replacement (men, four hours: 299+/-87 ml, six hours 350+/-101 ml; women, four hours: 187+/-30 ml, six hours: 219+/-31 ml) and in coronary artery bypass grafting (men, four hours: 197+/-69 ml, six hours: 242+/-83 ml; women, four hours: 128+/-15 ml, six hours: 173+/-18 ml). A blood loss of 400 ml was exceeded in 13% of men after valve replacement four and six hours postoperatively. In all other groups, less than 8% of patients had a loss of more than 400 ml both after four and after six hours. CONCLUSIONS: Postoperative drainage losses in elective cardiac surgery patients are small and a measurable advantage from retransfusion seems to be unlikely. We therefore endorse the routine use of shed mediastinal blood retransfusion in these patients.

Intravenous iron supplementation effect on tissue iron and hemoproteins in chronically phlebotomized lambs.

Chronic phlebotomy is an important mechanism of iron loss in premature infants. We studied inter- and intraorgan iron allocation in 10 twin lamb pairs undergoing an acute 40-50% reduction in red cell volume followed by smaller intermittent phlebotomies over an 11-day period. One twin received no supplemental iron sucrose, while the other received an average daily intravenous dose of iron sucrose of either 1 (n = 3), 2 (n = 3), 5 (n = 3), or 15 (n = 1) mg.kg-1.day-1. The total iron content of the red blood cells, liver, skeletal muscle, heart, and brain was directly related to iron dose up to 2 mg.kg-1.day-1. Tissue iron concentrations remained stable until liver iron was < 200 g/g dry wt, after which iron was preferentially directed to red blood cells over skeletal muscle, heart, and brain. Hemoprotein concentrations decreased proportionately to tissue iron, except myocardial cytochrome c, which remained preserved. Any available iron in phlebotomized, rapidly growing lambs is preferentially directed to red blood cells, and lambs require iron supplementation to maintain tissue iron and hemoprotein concentrations. A decrease in nonheme tissue iron results in the high prioritization of iron among iron-containing proteins.

The role of ascorbic acid and xylitol in etomidate-induced adrenocortical suppression in humans.

Etomidate-induced suppression of cortisol biosynthesis is a result of a blockade of 11-beta-hydroxylation in the adrenal gland, mediated by the imidazol radical of etomidate. Since the generation of steroids requires reductive and energy rich equivalents, the present study examined whether supplementation with ascorbic acid or xylitol, a major source of NADPH, could attenuate adrenal suppression by etomidate in human subjects by promoting the turnover rate of 11-beta-hydroxylase. During continuous etomidate/alfentanil anaesthesia for pelviscopic surgery 30 female patients received either Ringer's lactate, xylitol (0.25 g kg-1 h-1) or ascorbic acid (0.5 g h-1) intravenously (i.v.). The plasma concentrations of cortisol, aldosterone and dehydroepiandrosterone (DHEA) were recorded for 5 h after end of surgery and a stimulation with synthetic ACTH was performed. The results showed no evidence of a clinically relevant attenuating effect of ascorbic acid or xylitol on etomidate-induced adrenocortical suppression. However, the observed suppression of cortisol levels was not enough to allow an attenuating affect to be measured.

[Differential indications of non-opioid drugs for postoperative analgesia II. Quantification of the analgesic effect of a combination of metamizol plus diclofenac via patient-controlled analgesia]. / Untersuchungen zum differenzierten Einsatz von Nichtopioiden zur postoperativen Analgesie II. Quantifizierung des analgetischen Effektes der Kombination von Metamizol plus Diclofenac mittels der patientenkontrollierten Analgesie.

OBJECTIVE: In a previous study we investigated the analgesic efficacy of metamizol. After laparoscopic operations, in particular, the reduction of postoperative opioid requirements within the first 24 h after surgery attained clinical relevance (-67%). In the present study we investigated the analgesic efficacy of supplementary diclofenac. METHODS: 86 patients, scheduled for minor orthopaedic surgery, laparoscopic cholecystectomy or resection of the thyroid gland, participated in a doubleblind, randomised, placebo-controlled study. The setting was comparable to our previous study, apart from the supplementary administration of diclofenac. Before induction of anaesthesia, verum-treated patients received a diclofenac suppository (100 mg), in addition to metamizol (1 g/100 ml NaCl 0.9% intravenous over 15 min). These infusions were repeated at 6h and 12h. In addition to the third infusion, the patients received a further diclofenac suppository (100 mg). Cumulated doses of buprenorphine (PCA, patient-controlled analgesia), pain scores (0-10), blood pressure, pulse and side effects were recorded during the first 6 h and again at 24 h. RESULTS: All verum-treated patients had significantly less pain immediately after surgery and required lower cumulated doses of buprenorphine during the first 24 h after operation (laparoscopic cholecystectomy -33%, minor orthopaedic surgery -73%, resection of thyroid gland -60%). CONCLUSIONS: Combination of metamizol and diclofenac cause a clinically relevant reduction in opioid requirements, in particular after minor orthopaedic surgery and resection of the thyroid gland. There is no need for supplementary diclofenac following laparoscopic surgery.

The effects of illness on neonatal metabolism and nutritional management.

In summary, careful attention to nutrient delivery in the IUGR infant is important to prevent and treat neonatal metabolic derangements and to improve postnatal growth. Carbohydrates are the essential fuel in the first days of life, to prevent hypoglycemia. Subsequent delivery of protein and fat helps rectify reduced muscle and fat stores and promotes weight gain. Calcium supplementation to prevent further bone demineralization and iron supplementation to replete iron stores may be necessary. Of special interest is that the neurologic outcome of these infants appears linked to the rate of catch-up growth. The rate of postnatal head growth depends on many perinatal and neonatal risk factors, and is a strong predictor of early developmental outcome in low-birthweight infants. Insufficient energy delivery beyond 2 weeks postnatal age in SGA premature infants results in failure to initiate subsequent catch-up head growth, with consequently smaller head circumferences at 1-year follow-up.

Enhancement of fatty acid mobilization and oxidation by glucose-xylitol compared to glucose alone in posttraumatic and septic patients.

INTRODUCTION: The objective of this study was to provide further information about the influence of xylitol on glucose and fatty acid metabolism after trauma and during sepsis. METHODS: In study I 18 metabolically normal patients undergoing coronary artery bypass grafting operation were randomly assigned into three groups. Group I (C I, n = 6) received 2 mg/kgBW/min of glucose, group II (C II, n = 6) 2 mg/kgBW/min of a glucose/xylitol mixture (1:1) and group III (C III, n = 6) 1 ml/kgBW/min of an isotonic saline solution. Infusions were applied over a 24-h-period following operation. Concentrations of glucose, lactate, insulin and single free fatty acids were measured before and after surgery and at 6-h-intervals over 36 hours postoperatively. In study II 5 septic patients were intravenously given 4 mg/kgBW/min glucose over a 6-h-period. Energy supply was then changed to a glucose/xylitol (1:1) regimen in an equicaloric dosage of 4 mg/kgBW/min for six hours again. Hepatic glucose production ([6,6-d2]-glucose), palmitate oxidation ([1-13C]-palmitate) and lactate concentrations were analyzed at the end of each infusion regime with the help of stable isotope technique and an enzymatic test, respectively. RESULTS: In study I glucose and insulin concentrations in C II and III were significantly lower than in C I during the postoperative infusion period. Highest lactate concentrations were measured in C I after 6 hours of infusion. Free fatty acids in C I remained at significantly lower levels compared to C II and III until glucose infusion was stopped. In septic patients (study II) xylitol led to significant lower hepatic glucose production rates and lactate concentrations than glucose, whereas palmitate oxidation increased. CONCLUSIONS: During the acute phase after trauma and during sepsis a carbohydrate supplementation with xylitol was superior to glucose alone because high plasma glucose concentrations were avoided, highly energy consuming hepatic glucose production was reduced and the release and oxidative utilization of free fatty acids was enhanced.

A partially automated radioligand binding assay system for use in clinical and pharmaceutical research.

Using a Tecan robotic sample processor and IBM compatible PCs we have developed a flexible, partially automated radioligand binding assay system. It handles pipetting parameters of up to 16 saturation or competition experiments at a time with up to 24 radioligand- or competitor-concentrations in a range over 4 orders of magnitude per experiment. The system provides enough flexibility so that all pipetting parameters including different tube-, rack-sizes, sample volumina and pipetting sequences may be easily adapted to the large variety of experimental requirements in binding assays. It rationalizes and increases assay throughput (up to 70% spare of working time), improves reliance and reproducibility of results. Radioactive exposure is minimized to the time preparing the radioligand working solution and transferring the sample tubes to and from the sample processor. The system has proven effective in various investigations on binding interactions, as well as in clinical studies on receptor expression under physiologic, pathological and therapeutic conditions.