Blood/gas partition coefficients of halothane,isoflurane and sevoflurane in horse blood

Background. Blood/gas partition coefficients (_b/g) for volatileagents in horse blood are reported for halothane but not forisoflurane and sevoflurane. We measured the _b/g of halothane,isoflurane and sevoflurane in the blood of fasted horses. Thecorrelation with age, weight and some haematological and biochemicalvariables was studied. The temperature correction factor forisoflurane solubility was calculated. Methods. Twenty-four horses were randomly allocated to halothane(n=8), isoflurane (n=8) or sevoflurane (n=8). Blood sampleswere taken after 10 h’ fasting. Calculation of _b/g wasbased on the measurement of anaesthetic partial pressures inblood at 37 °C, which was achieved with tonometer equilibrationand headspace gas chromatography. Results. Mean _b/g was 1.66 (SD 0.06) for halothane, 0.92 (0.04)for isoflurane, and 0.47 (0.03) for sevoflurane. The _b/g valueswere all significantly lower than in humans (P<0.001). Nocorrelation was found between _b/g and weight, age, haematocrit,plasma triglycerides, cholesterol or total bilirubin. The changein isoflurane solubility per 1 °C temperature increase was–2.63 (0.13)%. Conclusion. The _b/g values of halothane, isoflurane and sevofluranein fasted horses are significantly lower than those reportedin humans. The _b/g for halothane in this study agrees with valuesreported in the literature but a positive correlation with plasmatriglycerides could not be confirmed. Knowledge of _b/g can refinemodels of anaesthetic uptake. Br J Anaesth 2003; 91: 276–8     

Low-dose ketamine affects immune responses in humans during the early postoperative period

Background: Anaesthesia and surgery are associated with impairment of theimmune system expressed as an excessive proinflammatory immuneresponse and suppression of cell-mediated immunity that mayaffect the course of the postoperative period. Addition of anaestheticagents capable of attenuating the alterations in perioperativeimmune function may exert a favourable effect on patients’healing. We have assessed the effect of preoperative administrationof a sub-anaesthetic dose of ketamine on the mitogen responseand production of interleukin (IL)-1ß, IL-2, IL-6,and tumour necrosis factor (TNF)- by peripheral blood mononuclearcells (PBMCs), as well as natural killer cell cytotoxicity (NKCC)in patients undergoing abdominal surgery. Methods: Seventeen patients admitted for elective abdominal surgery weregiven ketamine 0.15 mg kg^–1 i.v. 5 min before inductionof general anaesthesia. Nineteen patients received a similarvolume of isotonic saline 5 min before induction of the anaesthesia.PBMCs were isolated from venous blood before and 4, 24, 48,and 72 h after operation for IL-1ß, IL-2, IL-6, andTNF- secretion, and NKCC assessment. Results: Four hours after operation, the cells from patients in the ketaminegroup showed a significantly suppressed production of IL-6 (P< 0.01) compared with controls. The production of IL-2 didnot change from that of the preoperation samples. TNF- secretionwas significantly elevated in the control group 4 h after operation(P < 0.05). Conclusions: Addition of small doses of ketamine before induction of anaesthesiaresulted in attenuation of secretion of the proinflammatorycytokines IL-6 and TNF-, and in preservation of IL-2 productionat its preoperative level. It is suggested that this anaestheticmay be of value in preventing immune function alterations inthe early postoperative period.     

Ketamine increases the frequency of electroencephalographic bicoherence peak on the alpha spindle area induced with propofol

Background: The reticular and thalamocortical system is known to play aprominent role in spindle wave activity, and the spindle waveis related to the sedative effects of anaesthetics. Recently,bispectral analysis of the EEG has been developed as a bettermethod to indicate nonlinear regulation including the thalamocorticalsystem linking to the cortical area. In the present study, inorder to explore the interference of ketamine with the nonlinearregulation of the sub-cortical system, we examined the effectof ketamine on spindle waves through the bispectral analysis. Methods: The study included 21 patients. Anaesthesia was induced andmaintained using a propofol-TCI system (target-controlled infusion,with target concentration 3.5 µg ml^–1). An A-2000BIS monitor was used and the raw EEG signals were collectedvia an RS232 interface on a personal computer. Bicoherence,the normalized bispectrum, and power spectrum were analysedbefore and after i.v. administration of 1 mg kg^–1 racemicketamine. Results: Propofol caused peaks in both power and bicoherence spectra,with average frequencies of 10.6 (SD 0.9) Hz and 10.7 (1.0)Hz, respectively. The addition of ketamine significantly shiftedeach peak to frequencies of 14.4 (1.4) Hz and 13.6 (1.5) Hz,respectively [P < 0.05, mean (SD)]. Conclusions: Ketamine shifted the peaks of bicoherence induced by propofolto higher frequencies. This suggests that ketamine changes the spindle rhythms through the modulation of the nonlinear sub-corticalreverberating network.     

Viscosity and density of common anaesthetic gases: implications for flow measurements

Although viscosity (µ) is a crucial factor in measurementsof flow with a pneumotachograph, and density () also plays arole in the presence of turbulent flow, these material constantsare not available for the volatile anaesthetic agents commonlyadministered in clinical practice. Thus, we determined experimentallyµ and of pure volatile anaesthetic agents. Input impedanceof a rigid-wall polyethylene tube (Zt) was measured when thetube was filled with various mixtures of carrier gases (air,100% oxygen, 50% oxygen+50% nitrogen) to which different concentrationsof volatile anaesthetic inhalation agents (halothane, isoflurane,sevoflurane, and desflurane) had been added. µ and werecalculated from real and imaginary portions of Zt, respectively,using the appropriate physical equations. Multiple linear regressionwas applied to estimate µ and of pure volatile agents.Viscosity values of pure volatile agents were markedly lowerthan those for oxygen or nitrogen. Clinically applied concentrations,however, did not markedly affect the viscosity of the gas mixture(maximum of 3.5% decrease in µ for 2 MAC desflurane).In contrast, all of the volatile agents significantly affected even at routinely used concentrations. Our results suggestthat the composition of the carrier gas has a greater impacton viscosity than the amount and nature of the volatile anaestheticagent whereas density is more influenced by volatile agent concentrations.Thus, the need for a correction factor in flow measurementswith a pneumotachograph depends far more on the carrier gasthan the concentration of volatile agent administered, althoughthe latter may play a role in particular experimental or clinicalsettings. Br J Anaesth 2001; 87: 602–7     

Continuous cardiac output during off-pump coronary artery bypass surgery: pulse-contour analyses vs pulmonary artery thermodilution

Background: No gold standard method exists for monitoring continuous cardiacoutput (CO). In this study, the agreement between the two mostfrequently used methods, PiCCO pulse-contour analysis (PCCO)and STAT pulmonary artery thermodilution (STAT-CO), was assessedduring multiple-vessel off-pump coronary artery bypass (OPCAB)surgery. Methods: Thirty patients were enrolled in the study. Two time periodswere defined during surgery; Period 1 included positioning ofthe heart and stabilizer device and Period 2 included the coronaryocclusion. Measurements were obtained every minute during bothperiods. The agreement for the continuous CO and the changein CO (CO) was estimated using the Bland–Altman method. Results: Significant changes in mean arterial pressure (MAP), centralvenous saturation, PCCO and STAT-CO were seen only during Period1. MAP correlated only with changes in PCCO, (P < 0.001,r = 0.60). The mean difference (2SD) between PCCO and STAT-COranged from – 0.29 (1.82) to – 0.71 (2.57) litremin^–1, and the percentage error varied from 32 to 50%.For the CO measurements, the limits of agreements did not differbetween Period 1 and Period 2. In contrast, for the CO measurements,the limits of agreements were wider in Period 1 than in themore haemodynamically stable Period 2. Conclusions: PCCO and STAT-CO show large discrepancies in CO during OPCABsurgery. Clinically acceptable agreement was seen only for trendsin CO during haemodynamically stable periods.     

Comparison of the effects of gelatin and a modern hydroxyethyl starch solution on renal function and inflammatory response in elderly cardiac surgery patients

Background: The effects of hydroxyethylstarch (HES) 130/0.4 6% and gelatin4% on inflammation, endothelial integrity, and renal functionafter cardiac surgery were compared. Methods: Sixty patients aged >80 yr undergoing cardiac surgery wererandomized to receive gelatin (n=30) or HES 130/0.4 (n=30).The colloid was used in the priming of the cardiopulmonary bypasscircuit (500 ml) and for volume replacement until the secondpostoperative day (POD). Serum creatinine, creatinine clearance,IL-6, IL-10, intercellular adhesion molecule-1 (sICAM-1), urinaryglutathione transferase-, and neutrophil gelatinase-associatedlipocalin (NGAL) were measured perioperatively. Serum creatininewas also reported 60 days after discharge. Results: The mean(SD) volume of gelatin infused was 4180(440) ml, whichwas greater than the volume of HES infused 2910(330) ml (P=0.002).The mean(SD) volume of serum creatinine on the first POD was151(24) µmol litre^–1 in the gelatin group and 126(13)µmol litre^–1 in the HES group (P=0.004). Valuesfor the second POD were 161(0.26) and 133(16) µmol litre^–1,respectively (P=0.004). Creatinine clearance was lower in thegelatin group on the first POD [37(7) vs 46(8) ml min^–11.73 m² (P=0.004)] and the second POD [32(8) vs 45(10) ml min^–11.73 m² (P=0.002)]. Kidney function 60 days after dischargedid not differ between the groups. IL-6, IL-10, and sICAM-1were significantly lower in the HES group than in the gelatingroup on the first and second PODs. Urinary -GST increased inboth groups to a comparable extent. Urinary NGAL concentrationswere higher in the gelatin than in the HES patients 5 h aftersurgery and on the first and second PODs. Conclusions: In cardiac surgery patients aged >80 years, volume therapywith HES 130/0.4 6% was associated with less marked changesin kidney function and a less marked endothelial inflammatoryresponse than gelatin 4%.     

Anaesthetics and cardiac preconditioning. Part I. Signalling and cytoprotective mechanisms

Cardiac preconditioning represents the most potent and consistentlyreproducible method of rescuing heart tissue from undergoingirreversible ischaemic damage. Major milestones regarding theelucidation of this phenomenon have been passed in the lasttwo decades. The signalling and amplification cascades fromthe preconditioning stimulus, be it ischaemic or pharmacological,to the putative end-effectors, including the mechanisms involvedin cellular protection, are discussed in this review. Volatileanaesthetics and opioids effectively elicit pharmacologicalpreconditioning. Anaesthetic-induced preconditioning and ischaemicpreconditioning share many fundamental steps, including activationof G-protein-coupled receptors, multiple protein kinases andATP-sensitive potassium channels (K_ATP channels). Volatile anaestheticsprime the activation of the sarcolemmal and mitochondrial K_ATPchannels, the putative end-effectors of preconditioning, bystimulation of adenosine receptors and subsequent activationof protein kinase C (PKC) and by increased formation of nitricoxide and free oxygen radicals. In the case of desflurane, stimulationof - and ß-adrenergic receptors may also be of importance.Similarly, opioids activate - and -opioid receptors, and thisalso leads to PKC activation. Activated PKC acts as an amplifierof the preconditioning stimulus and stabilizes, by phosphorylation,the open state of the mitochondrial K_ATP channel (the main end-effectorin anaesthetic preconditioning) and the sarcolemmal K_ATP channel.The opening of K_ATP channels ultimately elicits cytoprotectionby decreasing cytosolic and mitochondrial Ca²⁺ overload. Br J Anaesth 2003; 91: 551–65     

Effect of low-dose ketamine on inflammatory response in off-pump coronary artery bypass graft surgery

Background: Off-pump coronary artery bypass graft surgery (OPCAB) is stillassociated with a marked systemic inflammatory response. Theaim of this study was to investigate whether pre-emptive, lowdose of ketamine, which has been reported to have anti-inflammatoryactivity in on-pump coronary artery bypass surgery, could reduceinflammatory response in low-risk patients undergoing OPCAB. Methods: In this prospective randomized-controlled trial, 50 patientswith stable angina and preserved myocardial function undergoingOPCAB were randomly assigned to receive either 0.5 mg kg^–1of ketamine (Ketamine group, n=25) or normal saline (Controlgroup, n=25) during induction of anaesthesia. Inflammatory markersincluding C-reactive protein (CRP), interleukin (IL)-6, tumournecrosis factor- (TNF-), and cardiac enzymes were measured previousto induction (T1), 4 h after surgery (T2), and the first andsecond days after the surgery (T3 and T4). Results: There were no significant intergroup differences in the serumconcentrations of the CRP, IL-6, and TNF- and cardiac enzymes.Pro-inflammatory markers and cardiac enzymes, except TNF-, wereall increased after the surgery compared with baseline valuesin both groups. Conclusions: Low-dose ketamine administered during anaesthesia inductiondid not exert any evident anti-inflammatory effect in termsof reducing the serum concentrations of pro-inflammatory markersin low-risk patients undergoing OPCAB.     

THE ROLE OF {alpha}1-ADRENOCEPTORS IN ADRENALINE INDUCED HYPERKALAEMIA

The hyperkalaemic action of adrenaline was investigated in 44anaesthetized domestic pigs. Plasma and epicardial concentrationsof K⁺ were measured, in the latter case with an ion-selectiveelectrode. Adrenaline 10 µg kg^–1 caused a rapidincrease in the plasma concentration of K⁺ from 4.2 to 5.9 mmollitre^–1. The magnitude and the time course of epicardialconcentration of K⁺ were similar. Alpha-adrenoceptor block witheither phentolamine 5 mg kg^–1 (non-selective block) orprazosin 0.1 mg kg^–1 (selective 1-adrenoceptor block)abolished the hyperkalaemic effect of adrenaline in the plasmaand on the epicardium. The 1-adrenoceptor agonist phenylephrineincreased the K⁺ concentration, but the 2-adrenoceptor agonistUK 14.304 did not cause any change in concentration. These resultssuggest that the hyperkalaemia induced by adrenaline occursin the interstitial fluid of the myocardium and is mediatedby 1-adrenoceptors. These findings may be important in patientsat risk of hyperkalaemia, with implications, for example, inthe use of suxamethonium during induction of anaesthesia.     

Expression and function of fibronectin receptors on peripheral mononuclear cells in IgA nephropathy

The ß1 integrin family, major adhesive receptors forthe extracellular matrix (ECM), have been reported to be presentin normal and diseased kidneys. Attachment of glomerular cellsto ECM is mediated by ß1 integrins. Several membersof the ß1 integrins are referred to as VLA (very lateactivation) antigens. Peripheral mononuclear cells also expressVLA antigens in both resting and activated states. We examinedthe expression and function of VLA antigens on peripheral lymphocytesand monocytes in patients with IgA nephropathy using monoclonalantibodies (mAbs) specific for VLA -chains. Peripheral lymphocytesfrom patients with IgA nephropathy expressed VLA-4 and 5, butnot VLA-1 2 or 3. Peripheral monocytes from patients with IgAnephropathy expressed VLA-2 4 and 5, but not VLA-1 or 3. Theexpression of VLA adhesive receptors was observed in healthyindividuals. Adhesion assay to fibronectin revealed augmentedadhesion of mononuclear cells in IgA nephropathy (P<0.05),and this increased adhesion was inhibited by mAbs to VLA-4 and5. The expression of ß1 integrins in IgA nephropathywas similar to that of healthy individuals, but the functionof these molecules in terms of adhesion to fibronectin thoughVLA-4 and VLA-5 is increased in these patients. These findingssuggest that the activation of fibronectin receptors on peripheralmononuclear cells plays an important role in the pathogenicprocess of IgA nephropathy.     

Alleviation of neuropathic pain by intrathecal injection of antisense oligonucleotides to p65 subunit of NF-kappaB

Background. Treatment of neuropathic pain remains a challenge.The current study investigated the therapeutic effect of intrathecaladministration of NF-B antisense oligodeoxynucleotides (ODNs)on mechanical allodynia and thermal hyperalgesia in a chronicconstriction injury (CCI) model of rats. Methods. Lumbar intrathecal catheters were implanted in maleSprague–Dawley rats and a CCI model was established. Thermaland mechanical nociceptive thresholds were assessed with pawwithdrawal latency (PWL) to radiant heat and von Frey filaments.The phosphorothioate-modified antisense ODNs to p65 subunitof NF-B were administered intrathecally on each of five consecutivedays post-CCI. Nuclear NF-B p65 expression was assessed by westernblot. Results. CCI induced mechanical allodynia and thermal hyperalgesiaand significantly increased NF-B p65 protein expression. Intrathecalinjection of antisense ODN markedly suppressed the expressionof NF-B p65 protein and significantly attenuated CCI-inducedmechanical allodynia and thermal hyperalgesia. Conclusion. The activation of NF-B pathway may contribute toneuropathic pain in CCI rats. Suppression of NF-B could be apotential new strategy for the treatment of neuropathic pain.     

EFFECT OF GENERAL ANAESTHESIA ON WHOLE BODY PROTEIN TURNOVER IN PATIENTS UNDERGOING ELECTIVE SURGERY

To determine if general anaesthesia alone or in conjunctionwith surgery alters body protein turnover, we studied six healthy,unpremedicated females undergoing elective total abdominal hysterectomy.Changes in protein metabolism, synthesis and breakdown wereestimated by an isotope dilution technique using a continuousinfusion of the stable isotope tracer, L-[1–¹³C]leucine,before anaesthesia (4 h), during anaesthesia alone (1 h), duringanaesthesia and surgery (1 h) and in the recovery period (2h). General anaesthesia comprised thiopentone, pancuronium,enflurane (1 MAC) and oxygen-enriched air. An isotopic steadystate in plasma ¹³C--ketoisocaproate (¹³C-KIC) and expired ¹³C-carbondioxide were obtained during the four periods. Collections ofplasma and expired air were made during the steady state periodsand plasma -KIC enrichment measured to indicate precursor poollabelling from which leucine flux (equal to protein breakdownin the post-absorptive state) and oxidation were calculated,and whole body protein synthesis was derived. Whole body proteinbreakdown did not change with anaesthesia, but decreased withboth surgery and during the acute recovery period (P < 0.05).Protein synthesis did not change with anaesthesia and surgery,but decreased significantly after surgery (P < 0.05).     

Identification of post-transplant anti-{alpha}5(IV) collagen alloantibodies in X-linked Alport syndrome

X-linked Alport syndrome (AS) is a heritable disorder whichis associated with mutations in the type IV collagen 5(IV) chaingene (COL4AS) located on chromosome X. Following renal transplantation,an average of 6% of male AS patients develop anti-GBM nephritis.We studied the specificity of the antibodies against type IVcollagen in the serum of a patient with COL4A5 partial deletion.The specificity of these alloantibodies was determined againstcollagenasedigested GBM, as well as against recombinant noncollagenous(NCl) domains of the type IV collagen 1(IV)—6(IV) chainsexpressed in Escherichia coli. Immunoblotting and ELISA demonstratedthat these antibodies bound specifically to the NCl domain of5(IV) collagen. There was no binding to the NCl domain of theother chains, including the Goodpasture antigen. CompetitiveELISA confirmed the results obtained by ELISA and immunoblotting.This patient developed alloantibodies directed against antigenspresent in the grafted kidney, but absent from his Alport kidney.The pathogenesis of post-transplantation glomerulonephritisin the Alport patient studied is thus similar to that of Goodpasturesyndrome, with the exception that the pathogenic antibodiesare targeted to another chain of type IV collagen.     

Perioperative thermal insulation: minimal clinically important differences?

Background. Reduction of heat losses from the skin by thermalinsulation is used to avoid perioperative hypothermia. However,there is little information about the physical properties ofvarious insulating materials used in the operating room. Methods. The following insulation materials were tested usinga validated manikin: cotton surgical drape tested in two andfour layers; Allegiance drape; 3M Steri-Drape; metallized plasticsheet; Thermadrape^TM; Barkey thermcare 1 tested in one and twolayers; hospital duvet tested in one and two layers. Heat lossfrom the surface of the manikin can be described as: Q^·=h·T·Awhere Q^· is heat flux, h is the heat exchange coefficient,T is the temperature gradient between the environment and surfaceand A is the area covered. The heat flux per unit area (Q^·A^–1)and surface temperature were measured with nine calibrated heat-fluxtransducers. The environmental temperature was measured usinga thermoanemometer. T was varied and h was determined by linearregression analysis as the slope of T vs Q^·A^–1.The reciprocal of h defines the insulation. Results. The insulation value of air was 0.61 Clo. The insulationvalues of the materials varied between 0.17 Clo (two layersof cotton surgical drapes) to 2.79 Clo (two layers of hospitalduvet). Conclusions. There are relevant differences between variousinsulating materials. The best commercially available materialdesigned for use in the operating room (Barkey thermcare 1)can reduce heat loss from the covered area by 45% when usedin two layers. Given the range of insulating materials availablefor outdoor activities, significant improvement in insulationof patients in the operating room is both possible and desirable. Br J Anaesth 2004; 92: 836–40     

ERRATUM

Equation (7) should read: dt = d/2f In the equation after equation (8) the right hand side shouldbegin, not (kv/2f), but (kv/2f)     

Acute effect of oral, intraperitoneal, and intravenous 1{alpha}-hydroxycholecalciferol on markers of bone metabolism

OBJECTIVE: To study the acute effect of 1-hydoxycholecalciferol (1-OHD₃)on serum levels of alkaline phosphatase, Ca²⁺, osteocalcin,parathyroid hormone (PTH), phosphate and type I and III procollagens(PICP and PIIINP respectively) in patients undergoing peritonealdialysis. Also, 1,25-(OH)₂D₃ was measured. DESIGN: Single doses of 1-OHD₃ (80 ng/kg body wt) were given in randomizedcross-over fashion, orally, intraperitoneally (i.p.) and intravenously(i.v.) on three occasions. Blood was sampled at 0, 1, 6, 12,and 24 h after administration of 1-OHD₃. MAIN RESULTS: Following oral administration of 1-OHD₃, a decrease in serumalkaline phosphatase was seen when levels at 1 and 6 h werecompared to baseline (P<0.05). Oral and i.v. drug administrationsresulted in an increasing trend in serum Ca²⁺ throughout thestudy (P<0.05). Moreover, a difference in serum Ca²⁺ wasfound when 24-h levels after oral 1-OHD₃ dose was compared tobaseline (P<0.05). Serum osteocalcin at 12 and 24 h afteroral 1-OHD₃ compared to baseline were increased (P<0.05).Intact PTH followed a circadian rhythm after all three routesof drug delivery. After 24 h, significant decreases of intactPTH were observed in the oral and i.v. group. No changes inserum phosphate and serum PICP levels were observed over timeafter oral, i.p., and i.v. delivery of 1-OHD₃However, serumPIIINP following oral and i.p. administration of 1-OHD₃ decreasedat 1 and 6 h (P<0.05). CONCLUSION: Oral and iv. administration of 1-OHD₃ does influence serum levelsof osteocalcin, PTH, and PIINP. Noticeable is the significantincrease in serum osteocalcin after oral administration of 1-OHD₃,the remarkable increase (22.6%) in osteocalcin 24 h after i.v.1-OHD₃, though not statistically significant, the increase inserum PTH levels 12 h following oral and i.v. doses of 1-OHD₃and the moderate effect on serum Ca²⁺ levels.     

In vitro effects of HA-1A (Centoxin) on cytokine production in whole blood from intensive care unit patients

The cytokines interleukin- 1ß (1L-1ß), interleukin-6(IL-6) and tumour necrosis factor- (TNF) have been implicatedin the pathophysiology of sepsis and the systemic inflammatoryresponse syndrome (SIRS). The anti-endotoxin antibody, HA-1A(Centoxin), introduced as a treatment for sepsis, was withdrawnbecause of possible toxicity in some patients. There has beenlittle investigation of the effects of HA-1A on cytokine production.Sixty-one whole blood samples from 15 intensive care unit (ICU)patients with SIRS were incubated for 24 h with HA-1A and concentrationsof cytokines determined. Concentrations of 1L-6 exceeded thosein samples incubated without HA-1A by more than 25% in fivepatients, of whom four died. One death occurred among 10 patientsfor whom 1L-6 concentrations did not increase (P = 0.03). Incubationwith HA-1A did not increase concentrations of 1L-1ßor TNF. HA-1A did not affect cytokine production in whole bloodfrom healthy subjects. HA-1A may induce 1L-6 production in wholeblood from some ICU patients and this response is associatedwith increased mortality. Immune therapies for treatment ofsepsis and SIRS require careful evaluation of their abilityto affect cytokine production, before they are introduced forgeneral use. Presented in part at the Anaesthetic Research Society, LondonMeeting, November 19–20, 1993 (British Journal of Anaesthesia1993; 72: 487P).     

Evaluation by histology, immunohistology and PCR of protocollized renal biopsies 1 week post-transplant in relation to subsequent rejection episodes

Renal biopsies were performed 1 week following renal transplantationat a time without clinical evidence of rejection in 43 patients(13 females, mean age 48 years range 18–60 and 30 males,mean age 43 years range 17–59 years). Thirty-six biopsieswere available for histological or immunohistochemical analysis.Immunohistochemical analyses were performed with monoclonalantibodies against leukocytes (CD45), monocytes (WT14), complementfactor 3 (C3), T-cells (Leu4), T-cell receptor ß and, tumour necrosis factor (TNF) IL-2 receptor (IL2-R, TAC), intercellularadhesion molecule-l (ICAMI) and HLA-DR. The slides were scoredsemiquantitatively with the observers having no knowledge ofclinical or patient data. TNF and IL-2R were also measured byquantative PCR. None of the studied parameters correlated todelayed graft function or graft loss. Histological analysisshowed that both focal interstitial infiltrate (18/35) and tubularbasement membrane disruption (11/35) were followed by a higherincidence of subsequent rejection (P = 0.03 and 0.02 respectively).Also positivity for WT14 around tubuli (P = 0.02) was associatedwith subsequent occurrence of rejection. The intensity of stainingof ICAM-I on PTC as well as TAC on proximal tubular cells wasassociated with the number of subsequent rejection episodes.The association between the IL-2 receptor and subsequent rejectionwas also found applying PCR to the tissue specimens. We conclude that the presence of focal interstitial infiltratesand tubulitis in 1-week biopsies from well-functioning graftscarries an increased risk of subsequent rejection. The observedinfiltrate outside the tubuli may consist of either monocytesor lymphocytes. Further studies, both in vitro and in vivo,applying immunohistochemical and molecular biological techniqueswill be necessary to further elucidate the role of adhesionmolecules and interleukins in early and ongoing rejection.     

Myofibroblasts, predictors of progression of mesangial IgA nephropathy?

The limited knowledge of the cellular mediators of renal scarringhampers progress in the management of progressive chronic renalfailure (CRF). We have studied 38 patients with biopsy-provenmesangial IgA nephropathy with emphasis on attempting to definethe role of myofibroblasts(-smooth muscle actin/SMA-positivecells) in renal scarring. In 18 untreated patients, correlationswere undertaken between known histological parameters of progressionas well as the presence of myofibroblasts in tissues and theclinical outcome. -SMA staining by an avidin-biotin-peroxidasemethod was confined to a large extent to the vascular smoothmuscle cells of normal kidneys but extended to the tubulointerstitiumand periglomerular space in scarred kidneys. Mild glomerularstaining was also noted. The interstitial immunostain followeda similar distribution to that of interstitial type III collagen.Morphometric analysis showed the interstitial SMA staining tobe a reliable histological predictor of outcome as it discriminatedbetween progressors and non-progressors (²=4.923, P=0.026).The intensity of the interstitial -SMA staining correlated withrenal functional outcome; inversely with the reciprocal of serumcreatinine slopes (r=-0.466, P<0.025) and positively withthe serum creatinine value at the end of the observation period(r=0.704, P<0.00l). Other histological parameters that correlatedwith outcome included the degree of tubulointerstitial (TI)inflammatory infiltrate (r=-0.425, P<0.05 with 1/Cr slopeand r=0.760, P< with serum creatinine) and the intensityof the TI staining for collagen IV (r=-0.567 and 0.667 respectively).In 20 patients treated with prednisolone and azathioprine, asecond renal biopsy showed the persistence of interstitial myofibroblastsin the absence of progressive fibrosis. In conclusion, stainingof renal biopsies of patients with mesangial IgA for -SMA-positivecells may identify the myofibroblasts as important mediatorsof TI scarring and have useful prognostic implications.     

An investigation to show the effect of lung fluid on impedance cardiac output in the anaesthetized dog

Background. Accumulation of lung fluid in the critically illpatient is believed to attenuate impedance cardiac output (CO_IC)measurements. However, this phenomenon has never been shownexperimentally. Methods. In eight anaesthetized and ventilated dogs (weight15–22 kg) a high-precision flow probe was placed on theascending aorta via a left thoracotomy incision and the directcardiac output (CO_FP) was measured. Simultaneous CO_IC measurementswere made using a RheoCardioMonitor (ACMA, Singapore). Lungoedema was induced by intravenous oleic acid 0.1 mg kg^–1.Lung fluid was assessed by the decrease in basal thoracic impedance(Z_b). Percentage errors between the two methods (CO_IC–CO_FP)were calculated and compared as Z_b decreased at 1 intervals. Results. During the experiment mean Z_b decreased from 35.9 (SD5.2) to 27.8 (6.5) (P=0.0037). This occurred over a periodof 225 (range 112–338) min and Z_b decreased by 1 every51 (22–68) min. The presence of excessive lung fluid wasconfirmed at post-mortem. Before lung oedema was induced, CO_ICwas 1.5 (0.6) litre min^–1 and the corresponding valueof CO_FP was1.5 (0.7) litre min^–1 (data from eight dogs).As Z_b decreased, and lung fluid accumulated, the error betweenCO_IC and CO_FP widened (P<0.0001, ANOVA for repeated measures).Eventually, CO_IC decreased to 0.7 (0.3) litre min^–1 andthe corresponding value of CO_FP was1.2 (0.3) litre min^–1(Z_b=5 , data from six dogs). Mean arterial pressure, centralvenous pressure and systemic vascular resistance were kept constant. Conclusion. The presence of lung fluid attenuates CO_IC measurementswith respect to CO_FP.