Good quality of life before cardiac arrest predicts good quality of life after resuscitation.

BACKGROUND: The survival rate of cardiac arrest patients is increasing. Our aim was to compare the quality of life before and after cardiac arrest and analyse the factors associated with outcome. METHODS: All adult cardiac arrest patients admitted to the Tampere University Hospital intensive care unit between 2009 and 2011 were included in a retrospective follow-up study if surviving to discharge and were asked to return a questionnaire after 6 months. Data on patient demographics and pre-arrest quality of life were retrieved from medical records. Data are given as means (SD) or medians [Q1 , Q3 ]. We used logistic regression to identify factors associated with better quality of life after cardiac arrest. RESULTS: Six months after cardiac arrest, 36% (79/222) were alive and 70% (55/79) of those patients completed the follow-up EuroQoL (EQ-5D) quality of life questionnaire. Median values for the EQ-5D before and after cardiac arrest were 0.89 [0.63, 1] and 0.89 [0.62, 1], respectively (P = 0.75). Only the EQ-5D prior to cardiac arrest was associated with better quality of life afterwards (OR 1.2; 95% CI 1.0-1.3; P = 0.02). CONCLUSIONS: Quality of life remained good after cardiac arrest especially in those patients who had good quality of life before cardiac arrest.

Predictive value of urine interleukin-18 in the evolution and outcome of acute kidney injury in critically ill adult patients.

BACKGROUND: Interleukin-18 (IL-18) is a pro-inflammatory protein, which mediates ischaemic tubular injury, and has been suggested to be a sensitive and specific biomarker for acute kidney injury (AKI). The predictive value of IL-18 in the diagnosis, evolution, and outcome of AKI in critically ill patients is still unclear. METHODS: We measured urine IL-18 from critically ill patients at intensive care unit (ICU) admission and 24 h. We evaluated the association of IL-18 with developing new AKI, renal replacement therapy (RRT), and 90-day mortality. We calculated areas under receiver operating characteristics curves (AUCs), best cut-off values, and positive likelihood ratios (LR+) for IL-18 concerning these endpoints. Additionally, we compared the predictive value of IL-18 at ICU admission to that of urine neutrophil gelatinase-associated lipocalin (NGAL). RESULTS: In this study population of 1439 patients the highest urine IL-18 during the first 24 h in the ICU associated with the development of AKI with an AUC [95% confidence interval (CI)] of 0.586 (0.546-0.627) and with the development of Stage 3 AKI with an AUC (95% CI) of 0.667 (0.591-0.774). IL-18 predicted the initiation of RRT with an AUC (95% CI) of 0.655 (0.572-0.739), and 90-day mortality with an AUC (95% CI) of 0.536 (0.497-0.574). CONCLUSIONS: IL-18 had poor-to-moderate ability to predict AKI, RRT, or 90-day mortality in this large cohort of critically ill patients. Thus, it should be used with caution for diagnostic or predictive purposes in the critically ill.

Cardiac arrest teams and medical emergency teams in Finland: a nationwide cross-sectional postal survey.

BACKGROUND: The implementation, characteristics and utilisation of cardiac arrest teams (CATs) and medical emergency teams (METs) in Finland are unknown. We aimed to evaluate how guidelines on advanced in-hospital resuscitation have been translated to practice. METHODS: A cross-sectional postal survey including all public hospitals providing anaesthetic services. RESULTS: Of the 55 hospitals, 51 (93%) participated in the study. All hospitals with intensive care units (university and central hospitals, n = 24) took part. In total, 88% of these hospitals (21/24) and 30% (8/27) of the small hospitals had CATs. Most hospitals with CATs (24/29) recorded team activations. A structured debriefing after a resuscitation attempt was organised in only one hospital. The median incidence of in-hospital cardiac arrest in Finland was 1.48 (Q1 = 0.93, Q3 = 1.93) per 1000 hospital admissions. METs had been implemented in 31% (16/51) of the hospitals. A physician participated in MET activation automatically in half (8/16) of the teams. Operating theatres (13/16), emergency departments (10/16) and paediatric wards (7/16) were the most common sites excluded from the METs' operational areas. The activation thresholds for vital signs varied between hospitals. The lower upper activation threshold for respiratory rate was associated with a higher MET activation rate. The national median MET activation rate was 2.3 (1.5, 4.8) per 1000 hospital admissions and 1.5 (0.96, 4.0) per every cardiac arrest. CONCLUSIONS: Current guidelines emphasise the preventative actions on in-hospital cardiac arrest. Practices are changing accordingly but are still suboptimal especially in central and district hospitals. Unified guidelines on rapid response systems are required.

The quality of manual chest compressions during transport--effect of the mattress assessed by dual accelerometers.

BACKGROUND: The quality of cardiopulmonary resuscitation (CPR) has an impact on survival. The quality may be impaired if the patient needs to be transported to the hospital with ongoing CPR. The aim of this study was to analyse whether the quality of CPR can be improved during transportation by using real-time audiovisual feedback. In addition, we sought to evaluate the real compression depths taking into account the mattress and stretcher effect. METHODS: Paramedics (n = 24) performed standard CPR on a Resusci Anne Mannequin in a moving ambulance. Participants were instructed to perform CPR according to European Resuscitation Council Resuscitation guidelines 2010. Each pair acted as their own controls performing CPR first without and then with the feedback device. Compression depth, rate and no-flow fraction and also the mattress effect were recorded by using dual accelerometers by two Philips, HeartStart MRx Q-CPR defibrillators. RESULTS: In the feedback phase, the mean compression depth increased from 51 (10) to 56 (5) mm (P < 0.001), and the percentage of compression fractions with adequate depth was 60% vs. 89% (P < 0.001). However, taking account of the mattress effect, the real depth was only 41 (8) vs. 44 (5) mm without and with feedback, respectively (P < 0.001). The values for compression rate did not differ. CONCLUSIONS: CPR quality was good during transportation in general. However, the results suggest that the feedback system improves CPR quality. Dual accelerometer measurements show, on the other hand, that the mattress effect may be a clinically relevant impediment to high quality CPR.

Vital dysfunctions after intensive care discharge: prevalence and impact on patient outcome.

BACKGROUND: Patients discharged from the intensive care unit (ICU) are at increased risk for serious adverse events (SAEs). Recording vital functions and comprehending the consequences of altered vitals on general wards may be suboptimal. This potentially endangers recovery after successful intensive care. We aimed to determine the prevalence of vital dysfunctions after ICU discharge and their effect on patient outcome. METHODS: A prospective observational study. Adult patients discharged from a tertiary referral hospital ICU to general wards without treatment limitations were visited 24 h afterwards; their vitals were measured and reported to ward staff. Attending ward nurse responsible for patient was interviewed. RESULTS: The cohort consisted of 184 patients who had survived the first 24 h on the ward without complications (age: 57 ± 16 years; male: 68%). The prevalence of objectively measured vital dysfunctions was 15%, and the attending nurse had been unusually concerned about the patient in 19% of cases. Of the 184 patients, 9.8% subsequently suffered an SAE. In a multivariate logistic regression model, only vital dysfunctions (odds ratio 3.79; 95% confidence interval 1.18-12.2) and nurse concern (3.63; 1.17-11.3) were independently associated with an increased incidence of SAE. Medical emergency team (MET) assistance was never considered necessary by ward staff. Sensitivity of observed altered vitals on SAEs was 50% and specificity 89%. Sensitivity of nurse concern was 26%, specificity 84%. CONCLUSIONS: Simple vital function measurement and attending ward nurse's subjective assessment facilitate early detection of post-ICU patients at risk. The threshold in seeking assistance through MET remains high.

Evaluation of sublingual microcirculatory blood flow in the critically ill.

BACKGROUND: The microcirculation regulates the supply of oxygen and nutrients to tissues. The sublingual region is frequently used as a window to microcirculation in critically ill patients. Numerous studies have reported impaired sublingual microcirculatory flow. We hypothesized that the quality of sidestream dark field imaging (SDF) recordings could be systematically analyzed to justify the monitoring of sublingual microcirculation in interventional studies or in clinical practice. METHODS: The sublingual microcirculation in critically ill patients with septic shock, open heart surgery, or alcoholic pancreatitis, and healthy subjects was recorded with a hand held SDF device by one trained investigator in observational setting. A total of 82 video recording sessions were performed and 240 video clips eligible for quality assessment were identified. Quality assessment was performed offline by two investigators independently and blinded for the origin of the video file. RESULTS: Of the 240 clips, pressure artifact was detected in 86 (36%), major blood in 5 (2.1%), major saliva in 21 (8.8%) and extreme brightness causing loss of visible capillaries in 16 (6.7%) clips. The dominating vessel architecture was multiple size vessels in 228 (95%) and repeating capillary loop motif in 12 (5.0%). The mean (± SD) relative size reduction during stabilization was -6.9% (± 4.7%). Excellent technical quality was detected in 74 of 240 (30.8%) recordings. CONCLUSIONS: Our findings highlight the need of a comprehensive training period and reporting of data quality before findings with SDF imaging can be accepted as surrogate end points in interventional studies or as guidance in clinical practice.

Vascular adhesion protein-1 and syndecan-1 in septic shock.

BACKGROUND: Constituents of vascular endothelial surface layer (glycocalyx), e.g. an anchor protein syndecan-1 (SDC-1), can be detected in plasma in many inflammatory conditions. In inflammation, vascular adhesion protein-1 (VAP-1) is rapidly translocated to the apical side of the endothelial cells and may be released to plasma in a soluble form. We hypothesized that glycocalyx injury coincides with VAP-1 activation on endothelial cells. To test the hypothesis, we measured SDC-1 and VAP-1 levels in 20 patients with septic shock. METHODS: A prospective observational study was conducted in two multidisciplinary critical care units in two tertiary academic teaching hospitals with 20 mechanically ventilated adult patients with septic shock, on days 1 and 4 of treatment. Twenty healthy adults were enrolled as a control group. Plasma SDC-1 content, serum VAP-1 activity, platelets, and leukocyte count were measured in septic shock group at baseline and at 72 h and compared with those of healthy controls. RESULTS: VAP-1 activity and SDC-1 content were significantly increased in septic patients' group (P < 0.01) in comparison with controls. VAP-1 activity and SDC-1 content correlated positively to each other, and negatively to platelet count. In the septic shock group SDC-1 correlated on day 1 to SOFA score. CONCLUSIONS: We found increased VAP-1 activity and SDC-1 content in critically ill patients with septic shock. Based on our results, the role of VAP-1 in shock pathogenesis should be studied with semicarbazide-sensitive amine oxidase activity blocking agents and substrate affinity testing.

Corticosteroid therapy in intensive care unit patients with PCR-confirmed influenza A(H1N1) infection in Finland.

OBJECTIVE: To evaluate the incidence, treatment, and outcome of influenza A(H1N1) in Finnish intensive care units (ICUs) with special reference to corticosteroid treatment. METHODS: During the H1N1 outbreak in Finland between 11 October and 31 December 2009, we prospectively evaluated all consecutive ICU patients with high suspicion of or confirmed pandemic influenza A(H1N1) infection. We assessed severity of acute disease and daily organ dysfunction. Ventilatory support and other concomitant treatments were evaluated and recorded daily throughout the ICU stay. The primary outcome was hospital mortality. RESULTS: During the 3-month period altogether 132 ICU patients were tested polymerase chain reaction-positive for influenza A(H1N1). Of these patients, 78% needed non-invasive or invasive ventilatory support. The median (interquartile) length of ICU stay was 4 [2-12] days. Hospital mortality was 10 of 132 [8%, 95% confidence interval (CI) 3-12%]. Corticosteroids were administered to 72 (55%) patients, but rescue therapies except prone positioning were infrequently used. Simplified Acute Physiology Score II and Sequential Organ Failure Assessment scores in patients with and without corticosteroid treatment were 31 [24-36] and 6 [2-8] vs. 22 [5-30] and 3 [2-6], respectively. The crude hospital mortality was not different in patients with corticosteroid treatment compared to those without: 8 of 72 (11%, 95% CI 4-19%) vs. 2 of 60 (3%, 95% CI 0-8%) (P = 0.11). CONCLUSIONS: The majority of H1N1 patients in ICUs received ventilatory support. Corticosteroids were administered to more than half of the patients. Despite being more severely ill, patients given corticosteroids had comparable hospital outcome with patients not given corticosteroids.

Lactate concentrations in the rectal lumen in patients in early septic shock.

BACKGROUND: Previously, we observed that rectal luminal lactate was higher in non-survivors compared with survivors of severe sepsis or septic shock persisting >24 h. The present study was initiated to further investigate this tentative association between rectal luminal lactate and mortality in a larger population of patients in early septic shock. METHODS: A prospective observational multicentre study of 130 patients with septic shock at six general ICU's of university hospitals. Six to 24 h after the onset of septic shock, the concentration of lactate in the rectal lumen was estimated by a 4-h equilibrium dialysis. Dialysate concentrations of lactate were determined using an auto-analyser. RESULTS: The overall 30-day mortality was 32%, with age and Simplified acute physiology scores II and sequential organ failure assessment scores being significantly higher in non-survivors. In contrast, there were no differences in concentrations of lactate in the rectal lumen [2.2 (1.4-4.1) and 2.8 (1.6-5.1) mmol/l (P=0.34)] (medians and 25th-75th percentiles) or arterial blood [2.1 (1.4-4.2) and 2.0 (1.3-3.2) mmol/l (P=0.15)] between non-survivors and survivors. The rectal-arterial difference of the lactate concentration was higher in survivors. There were no differences in blood pressure, noradrenaline dose or central venous oxygen saturation between the groups. CONCLUSION: In this prospective, observational study of unselected patients with early septic shock, there was no difference in the concentration of lactate in the rectal lumen between non-survivors and survivors. TRIAL REGISTRATION: Clinicaltrials.gov (no: NCT00197938).

Prehospital therapeutic hypothermia for comatose survivors of cardiac arrest: a randomized controlled trial.

BACKGROUND: Intravenous infusion of ice-cold fluid is considered a feasible method to induce mild therapeutic hypothermia in cardiac arrest survivors. However, only one randomized controlled trial evaluating this treatment exists. Furthermore, the implementation rate of prehospital cooling is low. The aim of this study was to evaluate the efficacy and safety of this method in comparison with conventional therapy with spontaneous cooling often observed in prehospital patients. METHODS: A randomized controlled trial was conducted in a physician-staffed helicopter emergency medical service. After successful initial resuscitation, patients were randomized to receive either +4 degrees C Ringer's solution with a target temperature of 33 degrees C or conventional fluid therapy. As an endpoint, nasopharyngeal temperature was recorded at the time of hospital admission. RESULTS: Out of 44 screened patients, 19 were analysed in the treatment group and 18 in the control group. The two groups were comparable in terms of baseline characteristics. The core temperature was markedly lower in the hypothermia group at the time of hospital admission (34.1+/-0.9 degrees C vs. 35.2+/-0.8 degrees C, P<0.001) after a comparable duration of transportation. Otherwise, there were no significant differences between the groups regarding safety or secondary outcome measures such as neurological outcome and mortality. CONCLUSION: Spontaneous cooling alone is insufficient to induce therapeutic hypothermia before hospital admission. Infusion of ice-cold fluid after return of spontaneous circulation was found to be well tolerated and effective. This method of cooling should be considered as an important first link in the 'cold chain' of prehospital comatose cardiac arrest survivors.

Effects of levosimendan on indocyanine green plasma disappearance rate and the gastric mucosal-arterial pCO2 gradient in abdominal aortic aneurysm surgery.

BACKGROUND: Levosimendan has a dual mechanism of action: it improves myocardial contractility and causes vasodilatation without increasing myocardial oxygen demand. In a laboratory setting, it selectively increases gastric mucosal oxygenation in particular and splanchnic perfusion in general. The aim of our study was to describe the effects of levosimendan on systemic and splanchnic circulation during and after abdominal aortic surgery. METHODS: Twenty abdominal aortic aneurysm surgery patients were randomized to receive either levosimendan (n=10) or placebo (n=10) in a double-blinded manner. Both the mode of anaesthesia and the surgical procedures were performed according to the local guidelines. Automatic gas tonometry was used to measure the gastric mucosal partial pressure of carbon dioxide. Systemic indocyanine green clearance plasma disappearance rate (ICG-PDR) was used to estimate the total splanchnic blood flow. RESULTS: The immediate post-operative recovery was uneventful in the two groups with a comparable, overnight length of stay in the intensive care unit. Cumulative doses of additional vasoactive drugs were comparable between the groups, with a tendency towards a higher cumulative dose of noradrenaline in the levosimendan group. After aortic clamping, the cardiac index was higher [4(3.8-4.7) l/min/m(2) vs. 2.6(2.3-3.6) l/min/m(2); P<0.05] and the gastric mucosal-arterial pCO(2) gradient was lower in levosimendan-treated patients [0.9(0.6-1.2) kPa vs. 1.7(1.2-2.1) kPa; (P<0.05)]. However, the total splanchnic blood flow, estimated by ICG-PDR, was comparable [29(21-29)% vs. 20(19-25)%; NS]. Organ dysfunction scores (sequential organ dysfunction assessment) were similar between the groups on the fifth post-operative day. CONCLUSION: Levosimendan favours gastric perfusion but appears not to have a major effect on total splanchnic perfusion in patients undergoing an elective aortic aneurysm operation.

Regulation of transpirational water loss in Quercus suber trees in a Mediterranean-type ecosystem.

Sap flux density in branches, leaf transpiration, stomatal conductance and leaf water potentials were measured in 16-year-old Quercus suber L. trees growing in a plantation in southern Portugal to understand how evergreen Mediterranean trees regulate water loss during summer drought. Leaf specific hydraulic conductance and leaf gas exchange were monitored during the progressive summer drought to establish how changes along the hydraulic pathway influence shoot responses. As soil water became limiting, leaf water potential, stomatal conductance and leaf transpiration declined significantly. Predawn leaf water potential reflected soil water potential measured at 1-m depth in the rhizospheres of most trees. The lowest predawn leaf water potential recorded during this period was -1.8 MPa. Mean maximum stomatal conductance declined from 300 to 50 mmol m(-2) s(-1), reducing transpiration from 6 to 2 mmol m(-2) s(-1). Changes in leaf gas exchange were attributed to reduced soil water availability, increased resistances along the hydraulic pathway and, hence, reduced leaf water supply. There was a strong coupling between changes in soil water content and stomatal conductance as well as between stomatal conductance and leaf specific hydraulic conductance. Despite significant seasonal differences among trees in predawn leaf water potential, stomatal conductance, leaf transpiration and leaf specific hydraulic conductance, there were no differences in midday leaf water potentials. The strong regulation of changes in leaf water potential in Q. suber both diurnally and seasonally is achieved through stomatal closure, which is sensitive to changes in both liquid and vapor phase conductance. This sensitivity allows for optimization of carbon and water resource use without compromising the root-shoot hydraulic link.

Increased steroid hormone secretion in mouse Leydig tumor cells after induction of cholesterol translocation by sphingomyelin degradation.

The effects of sphingomyelin degradation on [3H]cholesterol transfer from the cell surface to mitochondria were examined in mouse Leydig tumor cells. These cells were used since they utilize cholesterol for steroid hormone synthesis in the mitochondria, and also possess acyl-CoA: cholesterol acyl transferase (ACAT) activity in the endoplasmic reticulum. Exposure of glutaraldehyde-fixed mouse Leydig tumor cells to sphingomyelinase (50 mU/ml, 60 min) resulted in the degradation of about 50% of cell sphingomyelin, suggesting that only half of the sphingomyelin mass in these cells was located in the exoleaflet of the plasma membrane. The partial sphingomyelin degradation resulted in the translocation of cellular unesterified [3H]cholesterol from plasma membranes (cholesterol oxidase-susceptible) to intracellular compartments (oxidase-resistant). The fraction of [3H]cholesterol that was translocated, i.e., between 20 and 50%, varied with different [3H]cholesterol-labeling methods. Cholesterol translocation induced by sphingomyelin degradation subsequently led to the stimulation of ACAT activity, suggesting that a fraction of cell surface cholesterol was transported to the endoplasmic reticulum. The sphingomyelinase-induced [3H]cholesterol flow from the cell surface to the cell interior was also in part directed to the mitochondria, as evidenced by the increased secretion of [3H]steroid hormones. In addition, the cyclic AMP-induced activation of steroidogenesis was further enhanced by the sphingomyelinase-induced cholesterol translocation. Based on the current results, it seems evident that a significant portion of the translocated [3H]cholesterol made its way from plasma membranes into the mitochondria for steroidogenesis.

Effects of sphingomyelin degradation on cholesterol mobilization and efflux to high-density lipoproteins in cultured fibroblasts.

The hydrolysis of sphingomyelin from cellular plasma membranes imposes many consequences on cellular cholesterol homeostasis by causing a rapid and dramatic redistribution of plasma membrane cholesterol within the cells (Slotte, J.P. and Bierman, E.L. (1988) Biochem. J. 250, 653-658). The objective of this study was to examine the effects of an extracellular cholesterol acceptor on the directions of the sphingomyelinase-induced cholesterol flow in cultured fibroblasts. We have used HDL3 as a physiological acceptor for cholesterol, and measured the effects of sphingomyelin hydrolysis on efflux and endogenous esterification of cellular [3H]cholesterol. Treatment of cells with sphingomyelinase did induce a dramatically increased esterification of plasma-membrane-derived [3H]cholesterol. The presence of HDL3 in the medium (100 micrograms/ml) did not prevent or reduce the extent of the sphingomyelinase-induced cellular esterification of [3H]cholesterol. Degradation of cellular sphingomyelin (75% hydrolysis) also did not enhance the rate of [3H]cholesterol efflux from the plasma membranes to HDL3. In addition, we also observed that the degradation of sphingomyelin in the HDL3 particles (complete degradation) did not change the apparent rate of [3H]cholesterol transfer from HDL3 to the cells. These findings together indicate that hydrolysis of sphingomyelin did not markedly affect the rates of cholesterol surface transfer between HDL3 and cells. By whatever mechanism cholesterol is forced to be translocated from the plasma membranes subsequent to the degradation of sphingomyelin, it appears that the sterol flow is specifically directed towards the interior of the cells.

Physiological and morphological responses to water stress in two Acacia species from contrasting habitats.

Container-grown seedlings of Acacia tortilis Forsk. Hayne and A. xanthophloea Benth. were watered either every other day (well watered) or every 7 days (water-stressed) for 1 year in a greenhouse. Total plant dry mass (T(dm)), carbon allocation and water relations were measured monthly. Differences in leaf area (LA) accounted for differences in T(dm) between the species, and between well-watered and water-stressed plants. Reduction in LA as a result of water stress was attributed to reduced leaf initiation, leaf growth rate and leaf size. When subjected to prolonged water stress, Acacia xanthophloea wilted more rapidly than A. tortilis and, unlike A. tortilis, lost both leaves and branches. These differences between species were attributed to differences in the allocation of carbon between leaves and roots and in the ability to adjust osmotically. Rapid recovery in A. xanthophloea following the prolonged water-stress treatment was attributed to high cell wall elasticity. Previous exposure to water stress contributed to water-stress resistance and improved recovery after stress.

Soluble and membrane-bound catechol-O-methyltransferase in normal and malignant mammary gland.

The levels of 26 kDa-soluble (S) and 30 kDa-membrane-bound (MB) catechol-O-methyltransferase (COMT) polypeptides were determined in paired samples from normal and neoplastic breast tissue of 32 patients with breast cancer. Immunohistochemical staining showed that the COMT reaction in normal mammary tissue was restricted to the epithelial cells in the ducti and lobuli, whereas in the tumors a strong reaction was also seen in the malignant cells. The amounts of COMT proteins in tumors could not be correlated with various clinical or pathological parameters. Quantitative immunoblotting analysis revealed that the total amount of COMT proteins in tumors was more than 50% higher than in respective normal samples in 26 out of 32 patients. Five cases showed less than a 50% difference and in one case less COMT was detected in the tumor. In most cases the amount of both S- and MB-COMT forms was increased. The average amount of total COMT was 178 +/- 57 pg/microg total protein in normal tissue and 566 +/- 94 pg/microg total protein in tumor. Respective values for S-COMT were 137 +/- 52 pg/microg total protein in normal tissue and 369 +/- 62 pg/microg total protein in tumor and for MB-COMT 41 +/- 10 and 197 +/- 41 pg/microg total protein, respectively. Analysis of COMT-specific transcripts suggested that the COMT enzyme level in tumors is determined in some cases by transcriptional and in some cases by post-transcriptional mechanisms.

Prevention of systemic hyperlactatemia during splanchnic ischemia.

Arterial blood lactate increases as a result of poor tissue perfusion. In splanchnic hypoperfusion, increased hepatic lactate uptake may delay increases in arterial blood lactate. We hypothesized that during isolated reduction of mesenteric blood flow, maintaining systemic blood volume and flow by fluid resuscitation may prevent systemic hyperlactatemia and therefore mask splanchnic ischemia. In a randomized study, 7 pigs were subjected to 4 h of splanchnic hypoperfusion by reducing the superior mesenteric artery blood flow to 4 +/- 0.8 mL/kg min [mean +/- standard deviation (SD)]. Seven pigs served as controls. Fluid was administered in order to keep the pulmonary artery occlusion pressure at 5 to 8 mm Hg. Cardiac output, portal vein, superior mesenteric, and hepatic arterial blood flow were measured every 30 min. Arterial, mixed venous, hepatic, portal, and mesenteric venous blood lactate, and jejunal mucosal pCO2 were measured at baseline and thereafter at 30-min intervals. The initial decrease in portal venous blood flow in the ischemic animals was subsequently counterbalanced by increasing hepatic arterial blood flow from 2 +/- 1 mL x kg(-1) x min(-1) at baseline to 11 +/- 4 mL x kg(-1) x min(-1) [after 4 h of ischemia; mean +/- standard deviation (SD), P = 0.02]. Jejunal mucosal- and mesenteric vein-arterial pCO2 gradients increased in the ischemic group from 11 +/- 8 mm Hg to 73 +/- 5 mm Hg (P = 0.02), and from 10 +/- 4 mm Hg to 44 +/- 8 mm Hg, respectively (P = 0.02). Mesenteric and portal venous lactate increased in the ischemic animals from 1.1 +/- 0.3 mmol/L to 4.2 +/- 1.0 mmol/L (P = 0.02), and from 1.0 +/- 0.2 mmol/L to 1.6 +/- 0.3 mmol/L, respectively (P = 0,03). While mesenteric lactate production and hepatic lactate uptake increased in parallel in the ischemic animals from 5 +/- 6 micromol x kg(-1) x min(-1) to 14 +/- 5 micromol x kg(-1) x min(-1) (P = 0.04), and from 14 +/- 7 micromol x kg(-1) x min(-1) to 24 +/- 6 micromol x kg(-1) x min(-1), respectively (P = 0.02), hepatic venous and arterial lactate, and apparent splanchnic lactate uptake and extraction did not change. We conclude that the hepatic lactate uptake increases in response to hepatic lactate influx. Systemic hyperlactatemia and increased hepatic venous lactate concentrations are late consequences of mesenteric hypoperfusion if hypovolemia is prevented. The net exchange of lactate across the splanchnic region does not reflect hepato-portal lactate kinetics in this animal model of intestinal hypoperfusion.

Characterization of the rat catechol-O-methyltransferase gene proximal promoter: identification of a nuclear protein-DNA interaction that contributes to the tissue-specific regulation.

The methylating enzyme catechol-O-methyltransferase (COMT) is an important inactivator of substrates containing catechol-structure, such as catechol neurotransmitters and hormones. In previous studies, the rat COMT gene has been cloned and characterized, and it has been shown that the two COMT polypeptides, S- and MB-COMT, are expressed from one gene by cooperation of two separate promoters. One promoter, P2, functions constitutively, whereas the other, the proximal P1 promoter, is regulated in a tissue-specific manner. In this report, a more detailed analysis of the rat P1 promoter is presented. By using reporter gene constructs, it is shown that upstream sequences of the P1 promoter contain several regions that modulate the expression either positively or negatively. These experiments also show that the region between the MB- and S-ATG translation initiation codons is indispensable for the activity of this promoter. Analysis of this region by DNase I footprinting and gel retardation assays identified the presence of several DNA elements with SP1 and NF1 recognition site homologies that bound both liver and brain nuclear proteins. However, one 11-nucleotide-long DNA region containing an overlapping consensus binding sequence for CREB and C/EBP-like factors reacted only with the liver nuclear lysate. Supershift experiments suggest that the transcription factor C/EBPalpha mediates the tissue-specific expression of the rat COMT P1 promoter.

Structure of the rat catechol-O-methyltransferase gene: separate promoters are used to produce mRNAs for soluble and membrane-bound forms of the enzyme.

The enzyme catechol-O-methyltransferase (COMT) catalyzes the inactivation of catechol-containing molecules by methylation. The cDNAs for the rat and human COMT have recently been cloned and recombinant proteins expressed in prokaryotic and eukaryotic cells. We describe here the structure of the rat COMT gene and its 5'-flanking sequences. The gene spans at least 13 kb and is composed of 5 exons, the first one noncoding. The two ATG codons for the initiation of translation of the membrane-bound (MB-COMT) and soluble (S-COMT) forms of the enzyme reside in the second exon. The gene expresses two mRNA species of 1.6 kb and 1.9 kb that have different tissue distributions. The expression of the transcripts is regulated by at least two promoters, P1 and P2. The P1 promoter expresses the shorter transcript in a tissue-specific manner and is located between the ATG codons in the coding region of the longer transcript. The P2 promoter is constitutive and responsible for the expression of the longer transcript. The shorter 1.6-kb mRNA (S-mRNA) produces only the S-COMT polypeptide, whereas the longer 1.9-kb mRNA (MB-mRNA) is able to direct synthesis of both forms of the COMT enzyme.

Gastric mucosal systemic partial pressure of carbon dioxide (PCO(2)) gradient in experimental endotoxin shock in swine--comparison of two methods.

OBJECTIVES: Clinically applicable methods for continuous monitoring of visceral perfusion/metabolism do not exist. Gastric mucosal end-tidal partial pressure of carbon dioxide (PCO(2)) gradient has been used, but it has limitations, especially in patients with lung injury and increased dead space ventilation. We studied the agreement between gastric mucosal end-tidal (DPCO(2gas)) and gastric mucosal arterial PCO(2) (D((t-a))PCO(2)) gradients, and especially the effect of dead space ventilation (V(d)/V(t) ratio) on the agreement. We hypothesized that DPCO(2gas) can be used as a semi-continuous indicator of mucosal arterial PCO(2) gradient in sepsis. DESIGN: A randomized, controlled animal experiment. SETTING: National laboratory animal center. INTERVENTIONS: Twelvehour infusion of endotoxin in landrace pigs. MEASUREMENTS AND RESULTS: We measured end-tidal PCO(2) continuously, gastric mucosal PCO(2) every 10 min (gas tonometry) and arterial PCO(2) every 120 min. Carbon dioxide production and the V(d)/V(t) ratio were determined by indirect calorimetry. In the endotoxin group ( n=7) cardiac index increased and systemic vascular resistance decreased. Endotoxemia increased dead space ventilation by 27% ( p=0.001). Both DPCO(2gas) and D((t-a))PCO(2)increased significantly in the endotoxin group ( p<0.0001 and p=0.049, respectively). Control animals remained stable throughout the experiment. When we compared DPCO(2gas) and D((t-a))PCO(2)(Bland-Altman analysis), the bias and precision were 0.9 and 0.9 kPa in the control group and 2.0 and 2.2 kPa in the endotoxin group, respectively. The disagreement between DPCO(2gas) and D((t-a))PCO(2) increased as the V(d)/V(t) ratio increased. CONCLUSIONS: DPCO(2gas) is a clinically applicable method for continuous monitoring of visceral perfusion/metabolism. Septic lung injury and increased dead space ventilation decrease the accuracy of the method, but this may not be clinically important.