[False increased CK-MB value after cryoablation of the prostate without myocardial infarct]

The authors report on a profound increase in creatine kinase isoenzyme MB (CK-MB) activity in three patients following uneventful cryoablation of the prostate under general anaesthesia: Just after the arrival at the recovery room CK-MB levels were 321 U/l, 245 U/l and 433 U/l, respectively. Other clinical investigations as well as additional laboratory tests ruled out myocardial infarction in all three patients. Electrophoresis of the CK-isoenzymes revealed an increase in CK-BB activity and an increase in atypical CK-BB as a cause of these findings. The presence of these isoenzymes leading to interferences with the antibody commonly used in CK-MB assays could explain the determination of a false positive CK-MB elevation in the three patients. Moreover, it is shown that this method of CK-MB activity determination may result in CK-MB levels higher than 100% of the whole CK activity. In addition, it is discussed that in patients suffering from prostatic carcinoma or other malignoma, "non-CK-M elevations" may occur. Therefore, the authors conclude that after cryoablation of the prostate additional tests like troponin T test and 12 channel ECG are required to rule out suspected myocardial infarction.

Positive prostate-specific antigen circulating cells detected by reverse transcriptase-polymerase chain reaction does not imply the presence of prostatic micrometastases

OBJECTIVES

Detection of circulating tumor cells may improve the preoperative local staging of prostate cancers. The aim of this study was to perform enhanced reverse transcriptase-polymerase chain reaction (RT-PCR) of prostate-specific antigen (PSA) mRNA to define the predictive value of PSA-positive circulating cells in a large series of patients.

METHODS

The study included 46 patients with Stage T1 to T2 prostate cancer, 94 with benign prostatic hyperplasia (BPH), and 51 (including 9 women) with nonprostatic disease. PSA-positive cells from peripheral blood samples were detected by Southern blot analysis of the RT-PCR products. Original oligonucleotide primers were defined to exclusively detect the three PSA mRNA splices.

RESULTS

Circulating PSA-positive cells were observed in 8 (8.5%) of 94 patients with BPH, 10 (22%) of 46 with Stage T1 to T2 prostate cancer, and 9 (17.6%) of 51 with nonprostatic disease. The detection rate of PSA-positive circulating cells was significantly increased in patients with prostate cancer versus patients with BPH (P = 0.03). Among clinically localized prostate cancers with a Gleason score less than 8, a correlation was observed between PSA-positive circulating cells and Stage pT3 cancer (P = 0.038), capsular penetration (P = 0.04), and a positive margin (P = 0.038). The specificity of the assay for Stage pT3 cancer detection was 84.6%, with a positive predictive value of 60%.

CONCLUSIONS

Although RT-PCR assay may have a role in preoperative local staging, this study demonstrated the absence of tissue and tumor specificity of PSA-positive circulating cells, accounting for the weak positive predictive value of this technique.

The effect of the N-methyl-D-aspartate receptor antagonist dextromethorphan on perioperative brain injury in children undergoing cardiac surgery with cardiopulmonary bypass: results of a pilot study

Experimental evidence indicates a role of the N-methyl-D-aspartate receptor in the pathogenesis of brain injury occurring during cardiac surgery with cardiopulmonary bypass (CPB). Dextromethorphan is a noncompetitive antagonist of this receptor with a favorable safety profile. Thirteen children age 3-36 months undergoing cardiac surgery with expected CPB of 60 minutes or more were randomly assigned to treatment with dextromethorphan (36-38 mg/kg/day) or placebo administered by naso-gastric tube. Dextromethorphan was absorbed well and reached putative therapeutic levels in blood and cerebrospinal fluid. Adverse effects were not observed. Mild hemiparesis developed after operation in one child of each group, and severe encephalopathy in one of the placebo group. Sharp waves were recorded in postoperative continuous electroencephalography in all placebo (n = 7) but only in 2/6 dextromethorphan treated children (p = 0.02). Pre- and postoperative cranial magnetic resonance imaging (MRI) revealed less pronounced ventricular enlargement in the dextromethorphan group (not significant). An increase of periventricular white matter lesions was visible in two placebo-treated children only. No elevations of cerebrospinal fluid enzymes were observed in either group. Although children with dextromethorphan showed less abnormalities in electroencephalography and MRI, dissimilarities of the treatment groups by chance diminished conclusions to possible protective effects of dextromethorphan at this time.

[Genetic risk after high dose radioiodine therapy with regard to gonadal dose]

AIM

The genetic risk for the offspring of patients treated with high doses of radioiodine was to be assessed with special regard to the gonadal dose caused by diagnostic and therapeutic procedures.

METHODS

41 young females (aged between 19 and 39 years) and four young males (aged 26 to 36 years) treated with radioiodine because of a thyroid carcinoma were interviewed by use of a questionnaire. The course of pregnancy and birth history could be documented as well as the congenital and developmental conditions of 56 children.

RESULTS

The amount of radioactivity applied for therapy and whole body scans ranged over 4.144 and 35.15 GBq 1-131; the individual gonadal dose was calculated based on the MIRD model and ranged over 0.2 and 2.2 Sv (0.51 Sv at a mean). The period of time between the last radioiodine application and confinement was at least 9 months, not exceeding 14 years. As to the course of pregnancy and birth two early abortions, one extrauterine gravidity and one premature birth due to an insufficiency of the placenta were stated. In one case a chromosomal translocation 7/14 occurred as a genetic defect which lead to an interruption. The children's development was unconspicuous except of two cases of neurodermatitis as well as multiple allergies and an early closure of the anterior fontanelle in one child each.

CONCLUSION

Although the genetic risk is supposed to increase with the gonadal dose achieved (doubling dose 1 Sv) and the increased risk of any congenital anomaly was calculated as about 13% at a mean in our patients, the rate of genetic determined diseases was not elevated (1.8% or 1/57). Thus, no increase of genetic defects or congenital malformations was reported in a total of 408 children described in the literature and in our group.

Caudal clonidine and bupivacaine for combined epidural and general anaesthesia in children

BACKGROUND

Clonidine produces analgesia by actions on alpha 2-adrenoceptors and enhances both sensory and motor blockade from epidural injection of local anaesthetics. Low-dose clonidine has been used so far for caudal injection in children. Our aim was to study the perioperative effects of high-dose caudal clonidine when added to low concentration of bupivacaine for combined epidural and general anaesthesia in children.

METHODS

After induction of general anaesthesia caudal block was performed either with 1 ml.kg-1 bupivacaine 0.175% with the addition of clonidine 5 micrograms.kg-1 (n = 20), or with 1 ml.kg-1 bupivacaine 0.175% (n = 20). The intraoperative anaesthetic requirements, the perioperative haemodynamic effects, respiratory rate, sedation score, postoperative pain scores and side effects were assessed by a blinded observer. A patient-controlled analgesia system was used for postoperative pain relief. The quality of postoperative pain relief was assessed using Smiley's pain analogue scale.

RESULTS

Intraoperative haemodynamic responses did not differ between the groups. However, during emergence from general anaesthesia children in the clonidine group had significantly lower heart rates and blood pressure compared to children in the control group. In addition, heart rates and blood pressures were also lower in the clonidine group in the early postoperative period (P < 0.05). Postoperative analgesia was significantly better in the clonidine group as evidenced by the total number of requests (3 vs 12, P < 0.05) and the total amount of tramadol (20.5 mg vs 72.8 mg, P < 0.05) administered. The duration of the caudal analgesia was significantly longer in the clonidine group (20.9 +/- 7.4 h vs 14.4 +/- 10.9 h, P < 0.05).

CONCLUSION

Our results suggest that caudal clonidine 5 micrograms.kg-1 enhances and prolongs caudal blockade with bupivacaine (1.175% in children. It also blocks sympathoadrenergic responses during emergence from anaesthesia. Sedation and cardiovascular effects are observed up to 3 h into the postoperative period.

Intestinal formation of hypoxanthine and uric acid during endotoxemia

The objective of this study was to examine the intestinal metabolism of high-energy purine compounds as sensitive indicators of tissue ischemia during endotoxemia. Arterial (art) and portal venous (PV) concentrations as well as the intestinal net concentration changes of adenosine (ADO), hypoxanthine (Hypo), and uric acid (UA) were measured at baseline and after 60 and 120 min in rats that were subjected to a 1-hr continuous infusion of endotoxin (1.5 mg/kg; group E), and in control animals (group C). Furthermore, the arterial (SaO2) and portal venous oxygen saturation (S(PV)O2) was determined at the same time points. Animals in both groups remained normotensive throughout the study period and no differences in mean arterial blood pressure were observed. In both groups, adenosine concentrations remained constant throughout the study and no changes in the net concentration difference (NCD) of adenosine between arterial and portal venous blood were observed [ADO(NCD); baseline: group E, -23 +/- 46 nmole/L; group C, 17 +/- 84 nmole/L; 120 min: group E, 14 +/- 38 nmole/L; group C, 5 +/- 40 nmole/L]. In contrast to control animals, hypoxanthine and uric acid concentrations increased in arterial and portal venous blood in endotoxemic rats after 120 min. This was accompanied with an increase in the intestinal net concentration differences of both hypoxanthine and uric acid, indicating the gut as the predominant source of these two compounds during endotoxemia [Hypo(NCD); baseline: group E, -36 +/- 53 nmole/L; group C, -53 +/- 185 nmole/L; 120 min: group E, 538 +/- 211 nmole/L; group C, 99 +/- 100 nmole/L] [UA(NCD); baseline: group E, 2.04 +/- 1.62 micromole/L; group C, -0.04 +/- 1.11 micromole/L; 120 min: group E, 9.58 +/- 3.04 micromole/L; group C, 0.35 +/- 1.34 micromole/L]. Furthermore, in endotoxemic rats the portal venous oxygen saturation decreased despite unaltered arterial oxygen saturation [SaO2; baseline: group E, 95.2 +/- 0.9%; group C, 94.2 +/- 0.9%; 120 min: group E, 95.4 +/- 0.7%; group C, 96.4 +/- 0.9%] [S(PV)O2; baseline: group E, 86.2 +/- 3.1%; group C, 85.7 +/- 1.4%; 120 min: group E, 69.1 +/- 4.5%; group C, 82.3 +/- 1.9%]. These results indicate the presence of tissue ischemia in the intestinal tract during early, normotensive endotoxemia. Furthermore, because of the direct toxic damage mediated by oxygen radicals that are generated during the production of uric acid, intestinal mucosal injury observed during endotoxemia may be related to an enhancement of the ATP-degradation pathway.

Late glial swelling after acute cerebral hypoxia-ischemia in the neonatal rat: a combined magnetic resonance and histochemical study

Secondary brain damage after transient cerebral hypoxia-ischemia (HI) is caused by a cascade of cellular events. In this study, complementary methods of magnetic resonance imaging and histochemistry were used to investigate the formation of cytotoxic and vasogenic edema during secondary brain damage induced by transient HI in 7-d-old rats. To elicit injury, 21 rats underwent right common carotid artery ligation followed by 1.5 h of 8% O2 exposure. Sequential apparent diffusion coefficient (ADC) and transversal relaxation time (T2) weighted magnetic resonance imaging were recorded for up to 3 d in 13 7-d-old rats. Eight animals were killed at various intervals between the end of HI and 21 h of recovery to perform histochemical assays using neuronal and astrocytic markers. Changes of the ADC revealed a biphasic function for the evolution of cytotoxic edema during the recovery period. At the end of HI, the ADC in the ipsilateral cortex was significantly decreased. Upon reoxygenation, it returned transiently to normal followed by a secondary, although less pronounced, decline after 8-48 h. After this, the ADC rose steadily. From 8 h of recovery, the proportion of vasogenic edema steadily increased as indicated by the T2 prolongation. At 21 h, the majority of glial cells showed immunoreactivity for glial fibrillary acidic protein and were of larger size, whereas the neurons were apoptotic. These results indicate that the delayed cerebral injury is accompanied by late glial swelling in conjunction with an enlarged interstitial space due to cell damage.

Cardiovascular and renal actions of the endothelin(B) receptor in pigs

Previously we showed that blocking the endothelin (ET)A receptor subtype with BQ-153 inhibited the vasoconstrictor effects of intravenously administered ET-1. In the presence of the ET(A) antagonist, ET-1 produced marked reductions in myocardial contractility and renal blood flow. We postulated that either the ET(B) receptor, or some other, as yet unidentified, ET-receptor subtype mediated the observed hemodynamic changes. In anesthetized pigs, this hypothesis was tested by using a recently developed selective, high-affinity antagonist to the ET(B) receptor, BQ-788, and sarafotoxin S6c, a selective ET(B) agonist, to determine the contribution of this receptor subtype to cardiovascular function. Endothelin-1 (0.4 nmol/kg, i.v.) produced the characteristic biphasic hemodynamic responses, consisting of an initial transient reduction in mean arterial pressure (MAP; 83 +/- 3 to 72 +/- 4 mm Hg; n = 9) followed by a prolonged increase (112 +/- 4 mm Hg; p < 0.01). As well, cardiac output (-58%; p < 0.05), myocardial contractility (-19%; p < 0.01), and renal blood flow (63%; p < 0.05) decreased. Sarafotoxin S6c produced marked but transient reductions in MAP (p < 0.001), cardiac output (p < 0.01), myocardial contractility (p < 0.001), and renal blood flow (p < 0.05). BQ-788 (1.0 mg/kg, i.v.), administered 3 min before sarafotoxin S6c, inhibited its effects. BQ-788 also inhibited the initial transient reduction in MAP seen after the injection of ET-1, but the subsequent sustained pressor responses were enhanced as reflected in the greater increases in left ventricular pressure (p < 0.02), myocardial contractility (p < 0.05), MAP (p < 0.01), and a larger reduction in cardiac output (p < 0.05). The heart rate was not changed after the initial ET injection, but it increased 54% when the peptide was administered in the presence of BQ-788. The reduction in renal blood flow was still evident, and its magnitude (64%) remained the same (p < 0.01) after treatment with BQ-788. Only the combined administration of both the ET(A) (BQ-123) and ET(B) (BQ-788) receptor antagonists blocked the effects of ET-1 on renal blood flow (p < 0.05). These data confirm that BQ-788 is a selective and effective antagonist of the ET(B) receptor and show that activation of this receptor subtype is involved in the transient vasodilation provoked by ET-1. Additionally, the ET(B) receptor appears to oppose the vasoconstrictor effects of the ET(A) receptor, which clearly mediates vasoconstriction. Combined treatment with BQ-123 and BQ-788 attenuated the reductions in renal blood flow produced by ET-1. Furthermore, some actions of ET-1 were not blocked by these antagonists and cannot be attributed to either the ET(A) or ET(B) receptors. We hypothesize the existence of an additional ET receptor or a subtype of the ET(B) receptor that is insensitive to BQ-788.

Epidermal localization and protective effects of topically applied superoxide dismutase

Data from the literature, as well as our previous work, indicate a protective effect of superoxide dismutase (SOD) in topical application against UV-induced cutaneous damage. In the present article we show that pre-treatment of the skin with SOD protects against PUVA-induced inflammatory reactions not only in murine, but also in human skin. Using fluorescently labelled Cu,Zn SOD, epifluorescence microscopy and digital image processing, we demonstrate that the FITC fluorescence localizes in the stratum corneum and upper granulosa, as well as in the epidermal cell layer surrounding the lumina of the hair follicles. These findings were similar for murine and human skin. Since autofluorescence was eliminated by a special filter, it can be ascertained that the fluorescence observed in the tissues was due to FITC-labelled SOD.

Prospective longitudinal evaluation of men with initial prostate specific antigen levels of 4.0 ng./ml. or less

PURPOSE

We evaluated the 3-year longitudinal changes in serial serum prostate specific antigen (PSA) levels in men with an initial PSA of 4.0 ng./ml. or less and no suspicion of prostate cancer.

MATERIALS AND METHODS

A total of 760 men with an initial PSA of 4.0 ng./ml. or less plus a normal or suspicious digital rectal examination and a benign prostate biopsy was enrolled into an every 4-month PSA monitoring study.

RESULTS

Of the 559 men with an initial PSA of 2.0 ng./ml. or less only 3 (0.5%) had a persistently abnormal PSA for 3 years and 1 cancer (0.2%) was detected, and 48 men had a PSA velocity of 0.8 ng./ml. per year or more at year 1 but only 1 (2%) had a persistent rate of increase (2.4 ng./ml. per year) at 3 years. Of the 201 men with a PSA of 2.1 to 4.0 ng./ml. 85 had an abnormal PSA but only 37 (43%) met the criteria for biopsy. Only 8 of 23 biopsies (35%) revealed cancer. Of the 201 men 24 had a PSA velocity of 0.8 ng./ml. per year or more at year 1 but only 4 had persistence for 3 years. All 4 men had cancer but they were identified as at high risk by PSA criteria.

CONCLUSIONS

Men with a PSA of 2.0 ng./ml. or less are at low risk for an abnormal PSA or cancer within 3 years and annual monitoring may not be necessary. However, annual monitoring is clinically useful in men with an initial PSA of 2.1 to 4.0 ng./ml. Also, serial monitoring with interval testing in men whose PSA becomes greater than 4.0 ng./ml. is beneficial in identifying a high risk group requiring biopsy. Finally, PSA velocity did not add further to cancer detection in this population.

N-acetylcysteine attenuates endotoxin-induced leukocyte-endothelial cell adhesion and macromolecular leakage in vivo

OBJECTIVE

To determine the influence of N-acetylcysteine on endotoxin-induced leukocyte-endothelial cell adhesion, vascular leakage, and venular microhemodynamics.

DESIGN

Randomized, blinded, controlled trial.

SETTING

Experimental laboratory.

SUBJECTS

Thirty male Wistar rats.

INTERVENTIONS

After pretreatment with N-acetylcysteine (150 mg/kg; n = 40; group A) or 0.9% saline solution (n = 10; group B) animals were given an intravenous infusion of endotoxin (Escherichia coli lipopolysaccharide 026:B6; 2 mg/kg/hr) over 120 mins. Animals in the control group (n = 10; group C) received a volume-equivalent infusion of 0.9% saline solution.

MEASUREMENTS AND MAIN RESULTS

Leukocyte adherence, red cell velocity (VRBC), vessel diameters, venular wall shear rate, and macromolecular leakage were determined in mesenteric postcapillary venules using in vivo videomicroscopy at baseline and at 30, 50, 90, and 120 mins after the start of the endotoxin challenge. Endotoxin exposure induced a marked increase in adherent leukocytes (group B: baseline, 391 +/- 24 cells/mm2; 120 mins, 1268 +/- 131 cells/mm2; p < .01). N-acetylcysteine pretreatment attenuated the adherence of leukocytes during endotoxemia (baseline, 366 +/- 28 cells/mm2; 120 mins, 636 +/- 49 cells/mm2; p < .01 vs. baseline; p < .01 vs. group B). Leukocyte adherence in control animals (group C) did not increase significantly. Administration of N-acetylcysteine did not influence the decrease in VRBC observed during endotoxemia. In group B1 VRBC decreased during the infusion of endotoxin from 2.0 +/- 0.2 mm/sec at baseline to 1.1 +/- 0.2 mm/ sec after 120 mins (p < .01 vs. baseline; p < .05 vs. group C), and in group A from 2.2 +/- 0.2 mm/sec to 1.1 +/- 0.1 mm/sec after 120 mins (p < .01 vs. baseline; p < .05 vs. group C). In group C, VRBC remained unchanged (baseline, 1.7 +/- 0.2 mm/sec; at 120 mins, 1.5 +/- 0.2 mm/sec). The venular diameters remained unchanged in all groups during the entire study period. After 120 mins, the venular wall shear rate decreased from 502 +/- 62 secs-1 at baseline to 272 +/- 46 sec-1 in group B (p < .01), and from 563 +/- 45 secs-1 at baseline to 283 +/- 31 secs-1 in group A (p < .01). No differences in venular wall shear rate were observed between these groups. In group C, the venular wall shear rate remained unchanged (baseline, 457 +/- 54 secs-1; at 120 mins, 409 +/- 51 secs-1). Macromolecular leakage, expressed as perivenular/intravenular fluorescence intensity after injection of fluorescence-labeled albumin, increased from 0.29 +/- 0.03 to 0.58 +/- 0.03 (p < .01) during the infusion of endotoxin in group B. In contrast, pretreatment with N-acetylcysteine diminished the extravasation of albumin (baseline, 0.27 +/- 0.01; at 120 mins, 0.37 +/- 0.02; p < .01 vs. baseline; p < .01 vs. group B).

CONCLUSION

These results demonstrate that N-acetylcysteine attenuates endotoxin-induced alterations in leukocyte-endothelial cell adhesion and macromolecular leakage, suggesting N-acetylcysteine might be therapeutic in the prevention of endothelial damage in sepsis.

Gastric intramucosal pH: a predictor of survival in cardiac surgery patients with low cardiac output?

OBJECTIVE

To assess the value of gastric intramucosal pH measurement in patients with low output after cardiac surgery.

DESIGN

Prospective clinical study.

SETTING

University hospital.

PARTICIPANTS

Fifteen patients with low output after cardiac surgery were included. Those who survived the first postoperative day (n = 14) remained in the study.

INTERVENTIONS

Gastric intramucosal pH and arterial lactate concentrations were measured 6, 12, and 24 hours after admission to the intensive care unit. Intravenous infusion of buffer solutions was strictly avoided during the equilibration period and in the half hour before injection of saline into the gastric balloon of the tonometer.

MEASUREMENTS AND MAIN RESULTS

Eight patients survived during the 28-day observation period, and six patients died. On admission to the intensive care unit, no difference in cardiac index (1.56 v 1.54 L/min/m2) or pulmonary capillary wedge pressure (17.3 v 17.7 mmHg) was found between survivors and nonsurvivors. During the first 24 hours after surgery, arterial lactate was significantly higher in the nonsurvivor group (61 v 23 mg/dL), but there was no difference between the gastric intramucosal pH of survivors and nonsurvivors (7.41 v 7.42 on admission).

CONCLUSIONS

Calculated gastric mucosal pH is not an early predictor of survival in cardiac surgery patients with postoperative low cardiac output syndrome. Further studies are required to assess whether the gradient between arterial and intramucosal partial pressure of carbon dioxide (PCO2) might be a more useful predictive value.

Changes in intrathoracic fluid volumes during weaning from mechanical ventilation in patients after coronary artery bypass grafting

PURPOSE

Although it is known that weaning from mechanical ventilation is associated with alterations in intrathoracic pressure, lung volume, and venous return, changes in intrathoracic fluid volumes during weaning are not reported. Especially in patients with impaired cardiac function, the development of pulmonary edema during weaning has been described. Thus, we investigated changes in intrathoracic fluid volumes in patients after coronary artery bypass grafting after changing the ventilatory pattern from mechanical to spontaneous ventilation.

MATERIALS AND METHODS

Intrathoracic blood volume index (ITBVI), pulmonary blood volume index (PBVI), and extravascular lung water (EVLW) were calculated during mechanical ventilation (T1), T-piece breathing (T2), and spontaneous breathing after extubation of the trachea (T3) in 72 consecutive patients after coronary artery bypass grafting using a combined dye-thermal dilution method.

RESULTS

Changing from mechanical ventilation to T-piece breathing resulted in an increase in ITBVI from 880 +/- 22 mL/m2 to 970 +/- 22 mL/m2 (P < .01), and in PBVI from 162 +/- 6 mL/m2 to 173 +/- 6 mL/m2 (P < .01). After extubation of the trachea, both parameters decreased again (ITBVI, 879 +/- 20 mL/m2; PBVI, 160 +/- 7 mL/m2). EVLW remained unchanged after transition to T-piece breathing (T1, 5.8 +/- 0.3 mL/kg; T2, 6.0 +/- 0.3 mL/kg), but increased to 6.6 +/- 0.5 mL/kg (P < .01) after extubation of the trachea. However, pathological values of EVLW were not observed.

CONCLUSIONS

In patients after coronary artery bypass grafting, changes in intrathoracic intravascular fluid volumes during weaning are restricted to the period of T-piece breathing and reflect an increased venous return. The maintenance of EVLW in the normal range during weaning indicates that cardiac function was matched to this elevated preload.

Continuous versus intermittent thermodilution cardiac output measurement during orthotopic liver transplantation

We evaluated intermittent and continuous thermodilution cardiac output data in 12 patients undergoing orthotopic liver transplantation. Measurements were performed at 16 predefined time points between induction of anaesthesia and 3 h after reperfusion of the liver graft. Cardiac output measurements yielded 192 data pairs (intermittent cardiac output range: 1.8-18.9 l.min-1, continuous cardiac output range: 3.3-20.0 l.min-1). During most of the procedure the correlation between intermittent and continuous cardiac output measurements was significant (r = 0.87, p < 0.0001), accompanied with a bias of -0.240 l.min-1 and a degree of precision of 1.789 l.min-1 (< 10.0 l.min-1:1.137 l.min-1, > or = 10.0 l.min-1:2.220 l.min-1). However, in the early phases after caval clamping and after reperfusion, accuracy was not acceptable. Only during these phases did the difference between the mean values of pulmonary artery blood temperature and rectal temperature increase (after caval clamping) or decrease (after reperfusion). In conclusion, despite acceptable levels of accuracy and precision between intermittent and continuous cardiac output measurement under stable conditions, both methods showed markedly decreased accuracy and precision in the early phases after caval clamping and after reperfusion, possibly owing to increased thermal noise.

Effect of the 21-aminosteroid tirilazad mesylate on leukocyte adhesion and macromolecular leakage during endotoxemia

BACKGROUND

Interstitial accumulation of leukocytes has been related to the development of multiple organ failure after sepsis. Oxygen radicals are involved in the process of leukocyte adherence to the microvascular wall. This study investigates the effects of the oxygen radical scavenger tirilazad mesylate on leukocyte-endothelial interactions, macromolecular leakage, and microhemodynamics in mesenteric venules during endotoxemia.

METHODS

Male Wistar rats were randomly allocated to receive tirilazad mesylate (group A, n = 10), its vehicle (group B, n = 10), or saline 0.9% (group C, n = 10) before a 120-minute infusion of endotoxin (2 mg/kg/hr). Furthermore, a control group without receiving endotoxin (group D, n = 10) was investigated. Leukocyte adherence, emigration of leukocytes, and macromolecular leakage were determined in postcapillary venules of the mesentery by using intravital videomicroscopy.

RESULTS

During the administration of endotoxin the number of adherent leukocytes per square millimeter of vessel surface progressively increased in group B (baseline, 431 +/- 35 cells/mm2; 120 minutes, 1121 +/- 71 cells/mm2) and group C (baseline, 398 +/- 44 cells/mm2; 120 minutes, 1290 +/- 116 cells/mm2). In group A no increase in leukocyte adherence was observed after 120 minutes (baseline, 415 +/- 81 cells/mm2; 120 minutes, 638 +/- 87 cells/mm2). In control animals the leukocyte adherence remained unchanged (baseline, 347 +/- 41 cells/mm2; 120 minutes, 507 +/- 75 cells/mm2). After 120 minutes, tirilazad mesylate prevented the increase in leukocyte emigration observed in group B and C. Increased macromolecular leakage during endotoxemia (groups B and C) was not influenced by pretreatment with tirilazad. Tirilazad did not affect the decrease in red cell velocity, volumetric blood flow, and venular shear rate observed during endotoxemia.

CONCLUSIONS

This study demonstrates inhibitory effects of tirilazad on endotoxin-induced leukocyte adherence and emigration, suggesting a potential therapeutic role for this substance in the prevention of sepsis-induced multiple organ failure.

In-use contamination of propofol. A clinical study

Reports about post-operative infections associated with the use of propofol prompted us to investigate the in-use contamination of lipid-formulated intravenous (i.v.) anaesthetics used for general anaesthesia or for sedation of intensive care patients in this department. The level and incidence of extrinsic contamination of propofol ('Diprivan') and of another intravenous anaesthetic, etomidate, formulated in lipid solution ('Etomidat-lipuro') was found to be low during two study periods. However, the need to observe strict aseptic precautions in handling these intravenous drugs must be emphasized.

The cerebral 'no-reflow' phenomenon after cardiac arrest in rats--influence of low-flow reperfusion

OBJECTIVE

Experimental data indicate that early microcirculatory reperfusion is disturbed after cardiac arrest. We investigated the influence of prolonged cardiac arrest and basic life support (BLS) procedures on the quality of cerebral microcirculatory reperfusion.

MATERIALS AND METHODS

In mechanically ventilated male Wistar rats anesthetized with N2O and halothane, cardiac arrest was induced by electrical fibrillation. Ten animals (group I) were subjected to 17 min of cardiac arrest (no-flow). Nine additional animals (group II) underwent only 12 min of cardiac arrest (no-flow), which was followed by a 5-min phase of BLS (i.e. mechanical ventilation and external cardiac compressions). In both groups, advanced resuscitation procedures including mechanical ventilation, external cardiac massage, 0.2 mg kg-1 epinephrine, 0.5 mmol kg-1 NaHCO3, and defibrillation were started 17 min after induction of cardiac arrest. The perfusion of the cerebral microcirculation was visualized by injection of 0.3 g kg-1 15% fluorescein isothiocyanate (FITC)-albumin 5 min after restoration of spontaneous circulation (ROSC), and the animals were decapitated 2 min later. The left hemispheres were fixed in 4% formalin, and coronal sections of 200 microns thickness at three different standard levels of the rat brain were investigated using fluorescence microscopy. Areas without capillary filling (cerebral 'no-reflow') were identified and calculated.

RESULTS

ROSC could be achieved in five of 10 animals (50%) of group I, and in six of nine animals (67%) of group II (P = n.s.). The severity of cerebral 'no-reflow' was higher in group II compared with group I (6.9 +/- 7.6 vs. 0.7 +/- 0.7% of total sectional areas; P < or = 0.05). Two sham-operated animals showed homogeneous reperfusion.

CONCLUSIONS

Wistar rats did not develop a marked cerebral 'no-reflow' phenomenon after circulatory arrest. A relevant degree of cerebral 'no-reflow' occurred, however, in animals subjected to a phase of BLS before circulatory stabilization. Therefore, low-flow states following prolonged cardiocirculatory arrest may aggravate early cerebral microcirculatory reperfusion disorders.

Inhaled nitric oxide inhibits platelet aggregation after pulmonary embolism in pigs

BACKGROUND

Inhaled nitric oxide (NO) is reported to prolong bleeding time in animals and humans and to inhibit platelet aggregation in persons with acute respiratory distress syndrome. In pulmonary embolism (PE), inhibition of platelet aggregation appears useful because further thrombus formation may lead to right ventricular dysfunction that results in circulatory failure. In the present study, the effect of inhaled NO on platelet aggregation after acute massive PE was investigated.

METHODS

After acute massive PE was induced in 25 anesthetized pigs by injecting microspheres, 5, 20, 40, and 80 parts per million inhaled NO were administered stepwise for 10 min each in 11 animals (NO group). In the control group (n = 14). NO was not administered. Adenosine diphosphate-induced initial and maximal platelet aggregation were measured before PE (10), immediately after induction of PE (PE), at the end of each 10-min NO inhalation interval (t10-t40), and 15 min after cessation of NO inhalation (t55) in the NO group, and at corresponding times in the control group, respectively.

RESULTS

Two animals in the control group and one in the NO group died within 10 min after PE induction and were excluded from analysis. Peaking at t40 and t55, respectively, initial (-13 +/- 6%; P < 0.05) and maximal (+44 +/- 17%; P < 0.05) platelet aggregation increased significantly after PE in the control group. In contrast, NO administration after PE led to a significant decrease in initial (maximum decrease, -9 +/- 3% at t40; P < 0.05) and maximal (maximum decrease, -15 +/- 7% at t30; P < 0.05) platelet aggregation. In the NO group, platelet aggregation had returned to baseline levels again at t55. In addition, NO administration significantly decreased mean pulmonary artery pressure and significantly increased end-tidal carbon dioxide concentration and mean systemic blood pressure.

CONCLUSIONS

Inhaled NO has a systemic and rapidly reversible inhibitory effect on platelet aggregation after acute massive PE in pigs. This may be beneficial in treating acute massive PE.

Stereospecific effect of bupivacaine isomers on atrioventricular conduction in the isolated perfused guinea pig heart

BACKGROUND

The local anesthetic bupivacaine is an equal mixture of two optically active isomers known to exert different cardiotoxic profiles in vivo. Enantiomer-specific forms of bupivacaine may have differential effects on cardiovascular function, specifically on cardiac electrophysiology. The authors' aim was to determine if there were any direct functional differences in the cardiac effects of bupivacaine isomers. The isolated heart was used to avoid possible indirect cardiac effects of bupivacaine, such as autonomic nervous and hormonal influences, as well as preload and afterload factors.

METHODS

The hearts of 12 ketamine-anesthetized guinea pigs were perfused with Krebs-Ringer's solution (97% oxygen, 3% carbon dioxide) at constant perfusion pressure using the Langendorff technique. Atrial and ventricular bipolar electrodes were placed to measure heart rate (HR) and atrioventricular (AV) conduction time. Left ventricular pressure (LVP), coronary flow, and inflow and outflow oxygen tensions were also measured. Oxygen delivery, oxygen consumption (MVO2), and percentage of oxygen extraction were calculated. Each heart was perfused with increasing randomized concentrations (0.5, 1, 5, 10 microM) of both isomers and the racemate of bupivacaine.

RESULTS

Racemic and isomeric bupivacaine equally and dose dependently decreased cardiac function. At 10 microM bupivacaine these changes were HR, -17 +/- 2%; LVP, -50 +/- 3%; coronary flow, -20 +/- 4%; and MVO2, -46 +/- 4%. The (+) isomer significantly prolonged AV conduction compared with the racemate and the (-) isomer at all concentrations. At 10 microM, AV time was 54 +/- 6% longer with the (+) isomer and 30 +/- 4% longer with the (+/-) racemate than with the (-) isomer. The greater delay in AV time with the (+) than the racemate or (-) isomer led to a second-degree AV dissociation in 10 of 12 of hearts treated with (+) bupivacaine.

CONCLUSIONS

This study shows that bupivacaine has an enatiomer-specific effect to delay AV conduction and to produce second-degree AV dissociation in the isolated perfused heart. This suggests that bupivacaine isomers probably have differential effects on one or more ion-specific channels regulating AV conduction. Other measured direct cardiac effects of bupivacaine appear to be independent of the isomeric form.

Sequence analysis of two genomic regions containing the KIT and the FMS receptor tyrosine kinase genes

The KIT and FMS tyrosine kinase receptors, which are implicated in the control of cell growth and differentiation, stem through duplications from a common ancestor. We have conducted a detailed structural analysis of the two loci containing the KIT and FMS genes. The sequence of the approximately 90-kb KIT locus reveals the position and size of the 21 introns and of the 5' regulatory region of the KIT gene. The introns and the 3'-untranslated parts of KIT and FMS have been analyzed in parallel. Comparison of the two sequences shows that, while introns of both genes have extensively diverged in size and sequence, this divergence is, at least in part, due to intron expansion through internal duplications, as suggested by the discrete extant analogies. Repetitive elements as well as exon predictions obtained using the GRAIL and GENEFINDER programs are described in detail. These programs led us to identify a novel gene, designated SMF, immediately downstream of FMS, in the opposite orientation. This finding emphasizes the gene-rich characteristic of this genomic region.

[Carcinoid tumors and neuroendocrine carcinomas of the stomach. Prognosis and therapeutic management. Study of 6 cases]

The six reported cases were separated into 2 groups: 1) the tumors of sporadic type, carcinoids (n = 2) and neuro-endocrine carcinomas (n = 2); 2) the gastrin-promoted tumors (n = 2). The purpose of this retrospective study was to review for each group of tumors, the clinicopathologic characteristics, prognosis factors and optimal management. In the first group, patients with a small and well differentiated tumor revealed by digestive bleeding, were treated by wedge excision and are alive and well 24 and 22 years later; the patients with large, invasive and poorly differentiated tumors were treated by subtotal (n = 1) and total (n = 1) gastrectomy, and died 1 year and 3 years later with metastases. In the second group, one patient with a small asymptomatic carcinoid tumor revealing chronic atrophic gastritis, was treated by endoscopic resection, without recurrence 3 years later; another patient with asymptomatic multifocal carcinoid tumors (about 100) associated with Zollinger-Ellison syndrome and multiple endocrine neoplasia type 1, was treated by total gastrectomy and is alive and well 7 years later. No patient had carcinoid syndrome. Synaptophysin was the most sensitive marker and secretion of serotonine was detected in 2 tumors.

CONCLUSION

Sporadic carcinoids serotonin and neuro-endocrine carcinomas are life-threatening tumors and need aggressive surgical therapy: their prognosis depends on tumors size, histological differentiation and mostly on tumor extension. In contrast, gastrin-promoted carcinoids do not result in disseminated disease and death, and a rather conservative approach seems appropriate.

Differential effects of arginine vasopressin on isolated guinea pig heart function during perfusion at constant flow and constant pressure

8-Arginine vasopressin (AVP) is a powerful coronary vasoconstrictor as well as peripheral vasoconstrictor, but AVP also is reported to have negative cardiac inotropic and chronotropic effects in vitro and in vivo. Our aim was to examine the direct effects of coronary vasoconstriction by AVP on cardiac function and metabolism in isolated guinea pig hearts perfused either at a constant perfusion pressure (CPP) of 55 mm Hg or at a constant coronary flow (CCF) equal to the initial natural flow at constant pressure. Coronary vasoconstriction was elicited by perfusing hearts with increasing concentrations of AVP in random order. Variables assessed were atrial heart rate (HR), atrioventricular (AV) conduction time, left ventricular pressure (LVP), coronary flow, inflow and outflow O2 tensions, O2 delivery (Do2), oxygen consumption (MVo2), percentage oxygen extraction (%O2E) and cardiac efficiency (HR-LVP/MVo2). We found that AVP increased coronary vascular resistance more at CCF than at CPP. The decrease in coronary flow, as a function of AVP at CPP, produced concentration-dependent decreases in heart rate, LVP, and MVo2, a decrease in Do2/MVo2, increases in AV conduction time and %O2E, and no significant change in cardiac efficiency. In contrast, the increase in perfusion pressure as a function of AVP at CCF caused no change in HR and AV conduction time, much smaller decreases in LVP and Do2/MVo2, a smaller increase in %O2E, an increase rather than a decrease in MVo2, and a decrease in cardiac efficiency. Our results indicate that larger decreases in HR, LVP, MVo2, and Do2/MVo2, and the larger increases in AV conduction time and %O2E with the AVP-induced decrease in CF at CPP are consistent with myocardial depression resulting from reduced global perfusion. However, cardiac efficiency was maintained at CPP because the decreased HR and LVP product (cardiac work) matched the decrease in MVo2. At CCF, AVP did not directly produce myocardial depression, but the small time-dependent decrease in LVP over time was not matched by the increase in MVo2, so that cardiac efficiency was not maintained. The demonstration of an increase in MVo2 despite no change or a decrease in cardiac work by coronary vasoconstriction with AVP at CCF, but not at CPP, suggests that cardiac O2 use is dependent more on maintenance of CF, despite increased resistance to perfusion, rather than on maintenance of perfusion pressure. Our data agree that Gregg's phenomenon results from a hydraulic effect to distend coronary vasculature because when flow is not allowed to decrease during vasoconstriction, MVo2 increases even though HR is unchanged and LVP is slightly decreased. This is supported by the finding that AVP does not increase coronary vascular resistance during CCF as much as during CPP, so that O2 supply is better maintained to match MVo2.