Anaesthetic efficacy and postinduction hypotension with remimazolam compared with propofol: a multicentre randomised controlled trial

Remimazolam, a short-acting benzodiazepine, may be used for induction and maintenance of total intravenous anaesthesia, but its role in the management of patients with multiple comorbidities remains unclear. In this phase 3 randomised controlled trial, we compared the anaesthetic efficacy and the incidence of postinduction hypotension during total intravenous anaesthesia with remimazolam vs. propofol. A total of 365 patients (ASA physical status 3 or 4) scheduled for elective surgery were assigned randomly to receive total intravenous anaesthesia with remimazolam (n = 270) or propofol (n = 95). Primary outcome was anaesthetic effect, quantified as the percentage of time with Narcotrend® Index values ≤ 60, during surgery (skin incision to last skin suture), with a non-inferiority margin of -10%. Secondary outcome was the incidence of postinduction hypotensive events. Mean (SD) percentage of time with Narcotrend Index values ≤ 60 during surgery across all patients receiving remimazolam (93% (20.7)) was non-inferior to propofol (99% (4.2)), mean difference (97.5%CI) -6.28% (-8.89-infinite); p = 0.003. Mean (SD) number of postinduction hypotension events was 62 (38.1) and 71 (41.1) for patients allocated to the remimazolam and propofol groups, respectively; p = 0.015. Noradrenaline administration events (requirement for a bolus and/or infusion) were also lower in patients allocated to remimazolam compared with propofol (14 (13.5) vs. 20 (14.6), respectively; p < 0.001). In conclusion, in patients who were ASA physical status 3 or 4, the anaesthetic effect of remimazolam was non-inferior to propofol.

Helical TomoTherapy Total Lymphoid Irradiation and Hematopoietic Cell Transplantation for Kidney Transplant Tolerance in Rhesus Macaques

Development of a post-transplant kidney transplant tolerance induction protocol involving a novel total lymphoid irradiation (TLI) conditioning method in a rhesus macaque model is described. We examined the feasibility of acheiving tolerance to MHC 1-haplotype matched kidney transplants by establishing a mixed chimeric state with infusion of donor hematopoietic cells (HC) using TomoTherapy TLI. The chimeric state was hypothesized to permit the elimination of all immunosuppressive (IS) medications while preserving allograft function long-term without development of graft-versus-host-disease (GVHD) or rejection. An experimental group of 11 renal transplant recipients received the tolerance induction protocol and outcomes were compared to a control group (n = 7) that received the same conditioning but without donor HC infusion. Development of mixed chimerism and operational tolerance was accomplished in two recipients in the experimental group. Both recipients were withdrawn from all IS and continued to maintain normal renal allograft function for 4 years without rejection or GVHD. None of the animals in the control group achieved tolerance when IS was eliminated. This novel experimental model demonstrated the feasibility for inducing of long-term operational tolerance when mixed chimerism is achieved using a TLI post-transplant conditioning protocol in 1-haplotype matched non-human primate recipients of combined kidney and HC transplantation.

Tomotherapy Applied Total Lymphoid Irradiation and Allogeneic Hematopoietic Cell Transplantation Generates Mixed Chimerism in the Rhesus Macaque Model

Development of a new methodology to induce immunological chimerism after allogeneic hematopoietic cell (HC) transplantation in a rhesus macaque model is described. The chimeric state was achieved using a non-myeloablative, helical tomotherapy-based total lymphoid irradiation (TomoTLI) conditioning regimen followed by donor HC infusions between 1-haplotype matched donor/recipient pairs. The technique was tested as a feasibility study in an experimental group of seven rhesus macaques that received the novel TomoTLI tolerance protocol and HC allo-transplants. Two tomotherapy protocols were compared: TomoTLI (n = 5) and TomoTLI/total-body irradiation (TBI) (n = 2). Five of seven animals developed mixed chimerism. Three of five animals given the TomoTLI protocol generated transient mixed chimerism with no graft-versus-host disease (GVHD) with survival of 33, 152 and >180 days. However, the inclusion of belatacept in addition to a single fraction of TBI resulted in total chimerism and fatal GVHD in both animals, indicating an unacceptable conditioning regimen.

Upregulation of aryl hydrocarbon receptor expression in CD4 T lymphocytes during an immune response in vivo. (INM1P.431)

Activation of the aryl hydrocarbon receptor (AHR) can impact T-cell differentiation and the maintenance of tissue-resident T cells. AHR expression, measured by RT-PCR or Western blot has been shown to be low in most CD4 T-cell subsets with highest expression found after stimulation of naïve CD4 T cells under Th17 conditions in vitro. The current study measures AHR expression within CD4 T-cell subsets of naïve or skin-grafted mice using flow cytometry. Cells were freshly isolated from the spleen, lymph nodes or skin of either untreated mice or mice that underwent allogeneic skin transplant. AHR expression in cells from untreated mice was highest in IL-17A+ CD4 T cells, followed by FoxP3+ and IFNγ+ cells. Naïve, CD62L+ CD4 T cells had the lowest expression. AHR expression in splenic or lymph node CD4 T cells from skin-grafted mice was similar to naïve mice with 20 - 30 % of FoxP3+ and &lt;10% of FoxP3- being AHR+. However, CD4 T cells within the skin grafts showed elevated AHR expression compared to spleen or LN with 75 - 85 % of FoxP3+ and 40 - 70% of FoxP3- being AHR+. This is comparable to the &gt;90% AHR+ CD4 T cells found when splenocytes were stimulated in vitro with anti-CD3 antibody in the presence of TGFb and IL-6. We conclude that the up-regulation of AHR expression in CD4 T cells in vitro also happens during immune responses in vivo and is not restricted to a single T cell subset, and may be important in T cell differentiation, trafficking, and cytokine production.

Supplementation of the aryl hydrocarbon receptor ligand indole-3-carbinol protects mice from Clostridium difficult associated disease. (MUC5P.762)

We have previously presented the dramatic benefit in survival that the dietary aryl hydrocarbon receptor (AHR) ligand indole-3-carbinol (I3C) confers in C. difficile disease in mice. Other groups have demonstrated that γδ T cells and Tregs play an important role in preventing other models of colitis. The current study sought to determine whether dietary I3C could protect mice from C. difficile by increasing the amounts of protective γδ T cells and Tregs. Furthermore, we examined the role of I3C in preventing antibiotic mediated dysbiosis. Mice were fed an experimental AHR ligand free diet (“base”) or the same diet supplemented with I3C and then infected with C. difficile. Pre-infection, base mice had less γδ T cells and Tregs in their cecum compared to I3C mice. Furthermore, I3C mice had a more robust and less pathologic microbiome pre-infection. Post-infection, I3C mice continued to have higher levels of γδ T cells and Tregs. These data suggest that AHR ligand supplementation can protect the host from C. difficile by reducing antibiotic associated dysbiosis as well as augmenting the local immune system to be more protective from C. difficile associated inflammation. Given the poor treatment options currently available as well as the high morbidity of infection, this represents an exciting new therapeutic possibility.

Exposure to inhaled atmospheric particulate matter enhances autoimmunity. (BA6P.125)

Epidemiological studies have demonstrated a relationship between exposure to atmospheric particulate matter (PM) and autoimmune disease. Multiple mechanisms have been proposed, including our research showing PM exposure in vitro can enhance Th17 differentiation in an aryl hydrocarbon receptor-dependent manner. The current study sought to determine the impact of PM exposure in vivo on immunity outside of the lung. In the 1st experiment, male B6 mice (n = 4 per group) were treated every 3 days with either vehicle or 800ug of SRM1949b, a representative sample of urban dust particles, in 20ul PBS i.n. for a total of 5 doses. One day after the last dose, splenocytes were cultured for 4 days with anti-CD3 and cytokines were measured. Treatment with PM increased IL-17A 3-fold but had no impact on IFNγ expression. In the 2nd experiment, female B6 mice (n = 4 per group) were treated every 3 days with vehicle or PM for a total of 9 doses. On the day of the 5th dose, a standard EAE protocol commenced. Clinical scoring using a 5-point scale began on d7 and ended on d21. All mice in both groups displayed EAE symptoms. Mice treated with PM had significantly higher mean peak score (3.5 + 0.3 vs 2.5 + 0.3 for PBS), trended toward having a higher mean clinical score and had earlier onset of disease. Together, these data suggest that inhaled PM exposure can impact immune responses beyond the lung, and support a mechanism where inhaled pollution aggravates autoimmunity.

Influence of intensive care treatment on the protein binding of sufentanil and hydromorphone during pain therapy in postoperative cardiac surgery patients

BACKGROUND

Our objective was to evaluate the effect of intensive care treatment on the protein binding of sufentanil and hydromorphone in cardiac surgery patients during postoperative analgesia using a target-controlled infusion (TCI) and patient-controlled analgesia (PCA).

METHODS

Fifty adult patients were enrolled in this prospective randomized study; of which, 49 completed the study (age range 40-81 yr). Sufentanil was administered as an analgesic intraoperatively, and hydromorphone was dosed after operation with TCI and PCA until 8 a.m. on the first postoperative day. Arterial plasma samples were collected for drug and protein concentration measurements up to 24 h after cardiac surgery. Corresponding patient data were collected from the electronic patient data system. After explorative data analysis with principal component analysis, multivariate regression analysis and non-linear mixed effects modelling was used to study the effect of treatment on protein binding.

RESULTS

Data of 35 patients were analysed. The median protein binding of sufentanil and hydromorphone was 88.4% (IQ range 85.7-90.5%) and 11.6% (IQ range 9.5-14.3%), respectively. Free fraction of sufentanil increased towards the end of the study period, whereas hydromorphone free fraction remained nearly constant. The total sufentanil concentration and volume balance were identified as significant covariates for the protein binding of sufentanil. For the protein binding of hydromorphone, no significant covariate effects were found.

CONCLUSIONS

Sufentanil protein binding was significantly dependent on changes in the total drug concentration and volume balance addressing the importance of adequate dosing and fluid-guided therapy. Hydromorphone protein binding was nearly constant throughout the study period.

CLINICAL TRIAL REGISTRATION

EudraCT 2011-003648-31 and ClinicalTrials.gov: NCT01490268.

Environmental exposures alter T cell differentiation and aggravate airway disease through the Aryl Hydrocarbon Receptor (125.6)

Environmental exposures can aggravate airway disease. 10% of World Trade Center disaster responders developed asthma. Polycyclic aromatic hydrocarbon (PAH) levels were the highest ever reported. The Aryl Hydrocarbon Receptor (AHR) directs T-cell differentiation between FoxP3+ Regulatory T-cells and Th17 effector cells, and is the primary receptor for PAHs. Exposure to specific inhaled PAHs found in diesel exhaust particles (DEP), urban dust particles (UDP), and coal fly ash (CFA) has a direct effect on T-cell differentiation in an AHR-dependent manner, that enhances Th17 differentiation and hastens the development of asthma. Naïve CD4+ CD25- T cells from C57BL/6 mice were cultured under Th17 conditions. We utilized standard reference materials (SRM) representing PAHs from UDP, DEP, CFA in cultures and mixed lymphocyte cultures. Human epithelial cells were treated, and then examined for Epithelial to Mesenchymal Transition (EMT), in the presence of PBMC and SRMs. Finally we exposed lungs of mice in vivo to UDP intratracheally (IT). SRMs increased IL-2, IL-17, and IL-22 in the supernatant of naïve T-cells by bead array. SRMs increased IL-17 expression in MLCs. Both IL-17 and UDP were able to cause significant EMT. In lungs exposed to UDP, the AHR was activated and IL-17 was upregulated in tissue by qPCR. PAHs lead to a TH17 deviation in the lung through the AHR. This may play a role in aggravating airway disease in susceptible people, and will be a target for future treatment.

BAFF is increased in renal transplant patients following treatment with alemtuzumab

Alemtuzumab is a monoclonal antibody that depletes T and B cells and is used as induction therapy for renal transplant recipients. Without long-term calcineurin inhibitor (CNI) therapy, alemtuzumab-treated patients have a propensity to develop alloantibody and may undergo antibody-mediated rejection (AMR). In pursuit of a mechanistic explanation, we analyzed peripheral B cells and serum of these patients for BAFF (Blys) and BAFF-R, factors known to be integral for B-cell activation, survival, and homeostasis. Serum BAFF levels of 22/24 alemtuzumab-treated patients were above normal range, with average levels of 1967 pg/mL compared to 775 pg/mL in healthy controls (p = 0.006). BAFF remained elevated 2 years posttransplant in 78% of these patients. BAFF-R on CD19(+) B cells was significantly downregulated, suggesting ligand/receptor engagement. BAFF mRNA expression was increased 2-7-fold in CD14(+) cells of depleted patients, possibly linking monocytes to the BAFF dysregulation. Addition of recombinant BAFF to mixed lymphocyte cultures increased B-cell activation to alloantigen, as measured by CD25 and CD69 coexpression on CD19(+) cells. Of note, addition of sirolimus (SRL) augmented BAFF-enhanced B-cell activation whereas CNIs blocked it. These data suggest associations between BAFF/BAFF-R and AMR in alemtuzumab-treated patients.

Unaltered graft survival and intragraft lymphocytes infiltration in the cardiac allograft of Cxcr3-/- mouse recipients

Previous studies showed that absence of chemokine receptor Cxcr3 or its blockade prolong mouse cardiac allograft survival. We evaluated the effect of the CXCR3 receptor antagonist MRL-957 on cardiac allograft survival, and also examined the impact of anti-CXCR3 mAb in human CXCR3 knock-in mice. We found only a moderate increase in graft survival (10.5 and 16.6 days, p < 0.05) using either the antagonist or the antibody, respectively, compared to control (8.7 days). We re-evaluated cardiac allograft survival with two different lines of Cxcr3(-/-) mice. Interestingly, in our hands, neither of the independently derived Cxcr3(-/-) lines showed remarkable prolongation, with mean graft survival of 9.5 and 10.8 days, respectively. There was no difference in the number of infiltrating mononuclear cells, expansion of splenic T cells or IFN-gamma production of alloreactive T cells. Mechanistically, an increased other chemokine receptor fraction in the graft infiltrating CD8 T cells in Cxcr3(-/-) recipients compared to wild-type recipients suggested compensatory T-cell trafficking in the absence of Cxcr3. We conclude Cxcr3 may contribute to, but does not govern, leukocyte trafficking in this transplant model.

Pharmacokinetics and pharmacodynamics of GPI 15715 or fospropofol (Aquavan injection) - a water-soluble propofol prodrug

Propofol (2,6-diisopropylphenol) is inadequably soluble in water and is therefore formulated as a lipid emulsion. This may have disadvantages when propofol is used to provide total intravenous anaesthesia or especially during long-term sedation. There has been considerable interest in the development of new propofol formulations or propofol prodrugs. GPI 15715 or fospropofol (Aquavan injection; Guilford Pharmaceutical, Baltimore, MD) is the first water-soluble prodrug that has been thoroughly studied in human volunteers and patients. GPI 15751 or fospropofol is cleaved by alkaline phosphatase to phosphate, formaldehyde and propofol. Formaldehyde is rapidly metabolised to formate. Although a formate accumulation is the principal pathomechanism responsible for the toxicity of methanol ingestion, so far there has been no report of toxicity due to the administration of fospropofol or other phosphate ester prodrugs, such as fosphenytoin. Fosphenytoin has been successfully introduced into the market for the treatment of status epilepticus in 1996. The main side-effects were a feeling of paraesthesia after rapid i.v. administration of GPI 15715 or fospropofol, which has also been described for fosphenytoin. The pharmacokinetics of GPI 15715 or fospropofol could be described by a combined pharmacokinetic model with a submodel of two compartments for GPI 15715 and of three compartments for propofol(G). The liberated propofol(G) compared to lipid-formulated propofol showed unexpected pharmacokinetic and pharmacodynamic differences. We found a significantly greater V(c), V(dss), significantly shorter alpha- and beta-half-life and a longer MRT (mean residence time) for propofol(G). The pharmacodynamic potency of propofol(G) appears to be higher than propofol when measured by EEG and clinical signs of hypnosis. In summary, GPI 15715 or fospropofol was well suited to provide anaesthesia or conscious sedation.

Primingtechnik mit Cisatracurium

OBJECTIVE

Priming can significantly shorten the onset of nondepolarizing neuromuscular blocking agents (NNBA) measured at the adductor pollicis muscle (APM). In spite of the known risks, priming is very popular especially in cases where NNBAs with a long onset time are used. However, there are no data regarding the onset of action for a priming technique measured at the laryngeal muscles although these muscles are of great importance for conditions of intubation and patient safety. The aim of this study was to compare a bolus application and a priming technique with respect to the laryngeal onset time and peak effect.

PATIENT AND METHODS

After approval of the local ethics committee and written informed consent, 36 patients undergoing elective thyroid surgery were enrolled in the study. Anesthesia was induced and maintained with a target controlled infusion of propofol (target concentration 2.7-6.0 microg/ml) and infusion of remifentanil (0.25-0.75 microg/kgbw/min). After loss of consciousness, a tube with a surface electrode was placed into the trachea without the application of any neuromuscular blocking agent. Neuromuscular monitoring consisted of evoked electromyography (EMG) of the laryngeal adductor muscles via the surface electrode and evoked acceleromyography (TOF Guard) of the right adductor pollicis muscle (APM). After transcutaneous stimulation of the recurrent laryngeal nerve and ulnar nerve, either 0.9% NaCl followed by 0.1 mg/kgbw cisatracurium after 3 min (bolus group, n=12), a priming dose of 0.01 mg/kgbw cisatracurium followed by 0.09 mg/kgbw 3 min later (low dose priming group, n=12) or a priming dose of 0.015 mg/kgbw cisatracurium followed by cisatracurium 0.085 mg/kgbw 3 min later (high dose priming group, n=12) were injected. Lag time, onset time and peak effect of NMB were recorded and compared between the groups.

RESULTS

Demographic data, lag time and peak effect were comparable between the three groups. Onset time at the laryngeal muscles was significantly shorter in the high dose priming group (80+/-17 s), when compared to the low dose priming group (128+/-23 s) and bolus group (142+/-29 s). Onset time at the APM was also significantly shorter in the high dose priming group (154+/-35 s), when compared with the bolus group (226+/-76 s). The recovery of the neuromuscular function measured at the APM showed no differences between the groups.

CONCLUSION

Our results show that only high dose priming of cisatracurium can significantly shorten the laryngeal onset time. However, clinical routine use is not recommended due to possible side-effects.

Modelling the pharmacodynamic interaction between remifentanil and propofol by EEG-controlled dosing

BACKGROUND AND OBJECTIVE

Knowledge of the pharmacodynamic interaction between remifentanil and propofol is important to permit optimal dosage strategies. We studied this pharmacodynamic interaction using the median power frequency of the processed electroencephalogram as a control parameter for feedback-controlled dosing of propofol.

METHODS

Twenty-one patients were given total intravenous anaesthesia with remifentanil and propofol. During three target-controlled infusion regimens, the target concentrations of remifentanil (5, 10, 15 ng mL(-1)) and propofol dosing were automatically adjusted to keep the median power frequency in the range 2 +/- 0.5 Hz. In each patient and during each remifentanil target concentration, four arterial propofol/remifentanil concentration pairs were measured. The type of interaction was tested using the relative distance from the line of additivity and the isobole was modelled using Bernstein splines.

RESULTS

The results from 13 patients were used for data analysis. The measured remifentanil concentrations during the three targets were (mean +/- SD): 3.6 +/- 0.9, 8.1 +/- 2.5 and 12.4 +/- 2.8 ng mL(-1). The corresponding propofol concentrations were 2.64 +/- 0.86, 2.13 +/- 0.58 and 2.09 +/- 0.58 microg mL(-1). The data were best described with an additive type of interaction and the isobole was estimated using: ((c)Remifentanil/64.2 ng mL(-1)) + ((c)Propofol/2.61 microg mL(-1)) = 1.

CONCLUSIONS

Within the studied concentration range, remifentanil and propofol showed an additive type of pharmacodynamic interaction on the electroencephalogram.

Testing and modelling the interaction of alfentanil and propofol on the EEG

BACKGROUND AND OBJECTIVE

For total intravenous anaesthesia an opioid is often combined with a hypnotic. A supra-additive interaction has been reported for clinical signs such as loss of consciousness or loss of the eyelash reflex. This study investigated the type of interaction of alfentanil and propofol on the electroencephalogram.

METHODS

Twenty patients scheduled for abdominal surgery were enrolled in the study. Anaesthesia was induced and maintained with alfentanil and propofol. Each patient received a target-controlled infusion of alfentanil. Three target concentrations of 150, 225 and 300 ng mL(-1) were applied to each patient in random order. Propofol was added to the alfentanil infusion by a feedback system. The set point was the range of 1.5-2.5 Hz median frequency of the electroencephalogram. Four arterial blood samples were taken within the last 20 min of each period. The mean drug concentrations were used to determine the type of interaction and an isobole was estimated by fitting Bernstein spline functions to the data.

RESULTS

In 17 patients, all three alfentanil target concentrations could be administered. The test for supra-additivity as well as the isobole construction resulted in an additive type of interaction. The line of additivity cA/cA0 + cP/cP0 = 1 was best fitted for the values (standard deviation) cA0 = 1240 (51)ng mL(-1) and cP0 = 5.21 (0.36) microg mL(-1).

CONCLUSIONS

The type of interaction between alfentanil and propofol on the electroencephalogram in the investigated dose range is additive. This gives the freedom and need to select the appropriate dosing ratio of alfentanil and propofol by other considerations.

Effect of immunosuppressants on T-cell subsets observed in vivo using carboxy-fluorescein diacetate succinimidyl ester labeling

BACKGROUND

The in vivo effects of immunosuppressants on T cells are classically determined using animal models of organ transplantation. These methods are technically difficult and time consuming. A simple in vivo method is needed for screening new immunosuppressants.

METHODS

Donor mouse spleen cells were labeled with a fluorescent dye, carboxy-fluorescein diacetate succinimidyl ester (CFSE), and then injected into the blood of recipient severe combined immunodeficiency mice. Three days after the injection, spleen cells of the recipient mice were isolated and the proliferating alloreactive T cells were analyzed by flow cytometry.

RESULTS

In control recipient mice, 50% of the T cells were proliferating, consisting of both CD4+ and CD8+ T cells. In cyclosporine- or FK506-treated mice, T-cell proliferation was suppressed in the CD4 subset but not in the CD8 subset. On the contrary, T-cell proliferation was significantly reduced in the CD8 subset but not in the CD4 subset in recipient mice treated with rapamycin.

CONCLUSION

The present mouse model using carboxy-fluorescein diacetate succinimidyl ester labeling is simple and fast. It is useful for screening new immunosuppressants and for examining the effect on T-cell subsets.

Pharmacokinetics and pharmacodynamics of the new propofol prodrug GPI 15715 in rats

BACKGROUND AND OBJECTIVE

We studied the pharmacokinetics and pharmacodynamics of GPI 15715 (Aquavan injection), a new water-soluble prodrug metabolized to propofol by hydrolysis.

METHODS

Nine adult male Sprague-Dawley rats (398 +/- 31 g) received a bolus dose of 40 mg GPI 15715. The plasma concentrations of GPI 15715 and propofol were determined from arterial blood samples, and the pharmacokinetics of both compounds were investigated using compartment models whereby the elimination from the central compartment of GPI 15715 was used as drug input for the central compartment of propofol. Pharmacodynamics were assessed using the median frequency of the EEG power spectrum.

RESULTS

A maximum propofol concentration of 7.1 +/- 1.7 microg mL(-1) was reached 3.7 +/- 0.2 min after bolus administration. Pharmacokinetics were best described by two-compartment models. GPI 15715 showed a short half-life (2.9 +/- 0.2 and 23.9 +/- 9.9 min), an elimination rate constant of 0.18 +/- 0.01 min(-1) and a central volume of distribution of 0.25 +/- 0.02 L kg(-1). For propofol, the half-life was 1.9 +/- 0.1 and 45 +/- 7 min, the elimination rate constant was 0.15 +/- 0.02 min(-1) and the central volume of distribution was 2.3 +/- 0.6 L kg(-1). The maximum effect on the electroencephalogram (EEG)--EEG suppression for >4 s--occurred 6.5 +/- 1.2 min after bolus administration and baseline values of the EEG median frequency were regained 30 min later. The EEG effect could be described by a sigmoid Emax model including an effect compartment (E0 = 16.9 +/- 7.9 Hz, EC50 = 2.6 +/- 0.8 microg mL(-1), ke0 = 0.35 +/- 0.04 min(-1)).

CONCLUSIONS

Compared with known propofol formulations, propofol from GPI 15715 showed a longer half-life, an increased volume of distribution, a delayed onset, a sustained duration of action and a greater potency with respect to concentration.

Piceatannol in combination with low doses of cyclosporine A prolongs kidney allograft survival in a stringent rat transplantation model

BACKGROUND

The discovery of new immunosuppressive agents has enhanced short-term graft survival. However, current immunosuppressants often induce toxicities that limit their clinical use. Thus, there is a need for new immunosuppressants for use in clinical transplantation. Piceatannol blocks Syk and ZAP-70, tyrosine kinases involved in immune cell activation. We examined whether piceatannol prolongs kidney allograft survival in the stringent ACI-to-Lewis rat model.

METHODS

Kidney recipients were divided into four groups. Group 1 (n=8) received piceatannol 30 mg/kg per day intravenously and cyclosporine A (CsA) 2 mg/kg per day intramuscularly from day -3 to day 7 after transplantation. At day 8, piceatannol was reduced to 10 mg/kg per day and the combined treatment continued until day 60. Group 2 (n=9) received 2 mg/kg per day CsA alone from day -3 to day 60. Group 3 (n=4) received piceatannol alone as in group 1. Group 4 (n=2) received only the vehicle dimethyl sulfoxide from day -3 to day 60. Graft rejection was defined as either a serum creatinine level more than 2 mg/dL or animal death.

RESULTS

Group 1 animals survived for at least 115 days (n=8, P<0.05), with several animals maintaining their grafts for more than 200 days. In contrast, 8 of 9 animals in group 2 rejected their grafts within 10 days of transplantation; one animal survived for 71 days. Excellent graft function was maintained in group 1 animals despite withdrawal of immunosuppression.

CONCLUSIONS

These results are the first to show that piceatannol, when combined with subtherapeutic dosages of CsA, prevents graft rejection, suggesting that targeting Syk and Zap could be useful for preventing graft rejection.

[Propofol-remifentanil versus sevoflurane-remifentanil for anesthesia for pediatric procedures in infants, children and adolescents]

INTRODUCTION

The aim of this study was to compare total intravenous anaesthesia (TIVA) using propofol and remifentanil (P/R-group) and balanced anaesthesia (BA) using sevoflurane and remifentanil (S/R-group) for paediatric surgery.

PATIENTS AND METHODS

A total of 120 patients aged 6 months to 16 years scheduled for elective minor lower abdominal surgery were randomly assigned to receive either propofol (5-10 mg/kg/h) and remifentanil (0.125-1.0 microgram/kg/min) or sevoflurane (1.0-1.5 MAC) and remifentanil (0.125-1.0 microgram/kg/min). Perioperative haemodynamics as well as recovery and discharge times, PONV and side-effects were studied. The patients vigilance, comfort and pain intensity were assessed postoperatively using the objective pain discomfort scale, the Steward post-anaesthetic recovery score and a visual analogue scale.

RESULTS

Postoperative recovery (9.0 vs 11.6 min) and extubation times (11.8 vs. 15.0 min) as well as the time taken until a Steward post-anaesthetic recovery score > 3/4 (15.2 vs. 21.4 min) was reached were significantly shorter in the P/R-group. However, the length of time until discharge to the ward, postoperative comfort, pain intensity and analgesic requirements as well as PONV were comparable in both groups.

CONCLUSIONS

With regards to the investigated parameters, TIVA with propofol and remifentanil is equally effective as BA with sevoflurane and remifentanil in paediatric patients. However, considering the selected dosing regimen, recovery times were significantly shorter for children after TIVA.

Postoperative pain control following remifentanil-based anaesthesia for major abdominal surgery

Eighty patients undergoing major abdominal surgery using remifentanil-based anaesthesia were randomly allocated in a double-blind manner to receive an intravenous bolus of fentanyl, buprenorphine, morphine or piritramide 20 min before the end of surgery. A reduced dose was administered postoperatively when patients reported moderate pain. Subsequent analgesia was provided by patient-controlled analgesia (PCA). The mean time from the end of anaesthesia to spontaneous respiration was 9 +/- 5 min. At first pain assessment, 63% of patients reported no or mild pain; 80% of patients required the second opioid bolus, those receiving piritramide needed the bolus significantly later than patients receiving buprenorphine or fentanyl. First PCA requirement also occurred significantly later in the piritramide group. This technique provided effective postoperative pain relief and transition to routine PCA and did not compromise recovery.

[Predictability and precision of "target-controlled infusion" (TCI) of propofol with the "Disoprifusor TCI" system]

In Germany a TCI-system for propofol (Disoprifusor-TCI) has been commercially available since spring 1997. We investigated the prediction error and precision of this TCI system as part of a multicentre study. Bias, precision, blood concentrations and dosage of propofol were compared with patients receiving propofol via a manually controlled infusion device.

METHODS

After approval by the local Ethics Committee and written informed consent, 21 patients of ASA-classification I to III scheduled for major abdominal surgery received either a target controlled infusion (group T, Disoprifusor-TCI) or a manually controlled infusion (group M) of propofol. The propofol plasma concentrations were measured by HPLC. The prediction error for each measurement, the median prediction error (MDPE) or bias, the median absolute prediction error (MDAPE) or precision and the divergence (change of the prediction error over infusion time) were calculated for both groups.

RESULTS

For all patients in group T (n = 12) the bias of the TCI system was 6.7% and the precision 27.5%. For 70% of all measured plasma concentrations the absolute prediction error was < or = 37%. The divergence was -5.4% per hour. For all patients in group M (n = 9) the bias was 44.2% and the precision 50%. The mean amount of propofol infused per kilogram body weight and hour was significant higher in T (9.0 +/- 1.2 mg/kg/h) than in M (6.6 +/- 1.2 mg/kg/h, p < 0.005).

CONCLUSIONS

With a precision of 27.5% the investigated TCI system (Diprifusor-TCI) showed an acceptable inaccuracy, as for TCI-systems a median prediction error of +/- 30% has to be expected due to the inherent variability of pharmacokinetic parameters. Further studies will be necessary to find out whether the investigated TCI system for propofol may offer substantial advantages.

Analysis of primate renal allografts after T-cell depletion with anti-CD3-CRM9

BACKGROUND

FN18-CRM9 is a CD3-specific immunotoxin that is capable of depleting CD3+ T cells. Pretreatment of rhesus monkeys with this agent before transplantation can induce donor-specific tolerance and "split tolerance" to renal allografts.

METHODS

Heterotopic renal transplants were performed on monkeys that received posttransplant FN18-CRM9. Histological and immunohistological staining, as well as analysis of the intragraft cytokine profile by reverse transcriptase polymerase chain reaction, was performed on percutaneous allograft biopsies.

RESULTS

Experimental monkeys had significant prolongation of allograft survival. Although an interstitial, mononuclear cell infiltrate was seen in all of the renal transplants, there was minimal evidence of acute cellular rejection. Histological evidence of alloantibody-mediated damage was detected 3 to 5 months after transplantation in the monkeys treated with FN18-CRM9. Immunohistology demonstrated the reappearance of CD3+ and CD4+ T cells, as well as CD20+ B cells, in the grafts. Cytokine analysis demonstrated expression of interferon-gamma. An intact anti-donor IgG response was seen.

CONCLUSION

Treatment of monkeys with FN18-CRM9 immediately after transplantation significantly prolongs renal allograft survival. Allograft biopsies demonstrate a lack of acute cellular rejection; however, alloantibody-mediated graft damage and rejection occur, with an intact anti-donor IgG response. The intragraft expression of the interferon-gamma may reflect this ongoing humoral rejection. These data suggest that even a brief period of T-cell allosensitization may lead to humorally mediated allograft damage. Efforts to achieve tolerance with posttransplant FN18-CRM9 will require modification of the protocol to deplete T cells before allosensitization exposure or to supplement the posttransplant immunomodification strategy.

FN18-CRM9 immunotoxin promotes tolerance in primate renal allografts

BACKGROUND

Transplant tolerance, rather than immunity, may be favored in the setting of a lower mature lymphoid mass in the recipient induced by anti-T cell agents. A novel immunosuppressive agent, FN18-CRM9, known to specifically kill T cells with great potency, was evaluated in a transplant model.

METHODS

In order to ablate recipient T cells, the immunotoxin FN18-CRM9 was administered to rhesus monkey recipients of MHC-mismatched renal allografts. Donor lymphocytes were injected intrathymically into some animals.

RESULTS

All monkeys with T-cell depletion by immunotoxin had prolonged allograft survival, and tolerance confirmed by skin grafting has been confirmed in five of six long-surviving recipients.

CONCLUSIONS

In this clinically relevant model, profound but transient T-cell depletion by a single agent substantially promotes tolerance.

Immunohistochemical study of cells positive for glial fibrillary acidic protein (GFAP) in the human pituitary gland, with special reference to folliculo-stellate cells

The cytology and the distribution of cells which contain glial fibrillary acidic protein (GFAP) were studied immunohistochemically in thick frozen sections of human pituitary glands. Immunoreactive cells were constantly demonstrated in both neuro- and adenohypophysis. In the neural lobe, an irregular network of long GFAP-positive pituicyte processes was revealed. Within this network, some asymmetric pituicytes became visible. A variable number of cells was stained in cell cords and follicles of the pars distalis and the intermediate zone. The morphology of these cells could be studied in detail, providing strong evidence to support the hypothesis that adenohypophyseal GFAP-immunoreactive cells belong to the folliculo-stellate (FS) cell system. Cells with similar cytological features in the pars distalis or the intermediate zone were found to share common immunoreactivities against GFAP and the presumable FS cell markers vimentin and S-100 protein. Our results corroborate the notion that, in the human pituitary, GFAP can be regarded as a marker protein of pituicytes and FS cells, which is expressed at varying degrees.

Unusual configurations of endoplasmic reticulum in pinealocytes of the Djungarian hamster (Phodopus sungorus)

Ultrastructural observations of the pineal gland of Phodopus sungorus revealed different morphological forms of endoplasmic reticulum. These included crystalloids composed of 200A-wide tubules with an intervening space of 200A and connected at right angles to form a rectangular lattice; complexes of undulating 500A-wide tubules in an electron-dense cytoplasmic matrix; and stacks of flattened cisternae covered with granular electron-dense material. All these structures are continuous with the surrounding endoplasmic reticulum. Frequently one structure is directly connected with another. The exact function of these structures derived from the endoplasmic reticulum is still unclear, but they can be assumed to be morphological features of augmented secretory activity.

[Efficacy of intravenous administration of calcium on sinus dysfunction developed under diltiazem. Apropos of 4 cases]

Four cases of sinus node dysfunction with junctional escape which developed during oral treatment with diltiazem in the usual therapeutic doses (180 to 240 mg/day) are reported. In one case the cardiac toxicity of diltiazem may have been potentiated by amiodarone taken concomitantly. In two cases a biological liver alteration may have modified the metabolism of diltiazem by slowing down its degradation. In all 4 patients, a slow intravenous injection of 1 g of calcium chloride resulted in rapid and lasting restoration of a normal sinus rhythm, making temporary ventricular pacing unnecessary. The authors underline the value of calcium administration as a therapeutic test in all disorders of cardiac rhythm or conduction occurring in patients treated with calcium channel blocking agents.

[Sinusal dysfunction secondary to the ingestion of diltiazem, cured by the administration of intravenous calcium]

An elderly patient, receiving long-term oral diltiazem at the usual dosage, presented a sudden attack of junctional bradycardia at 35 b X min-1; this was badly tolerated by the patient. The diltiazem blood level was normal. After recovery, nodal investigations were also normal. The treatment of this accident due to a calcium-blocker is stressed: the intravenous injection of a calcium salt only was sufficient, with a return to near-normal sinus function, so avoiding the necessity of pacing.

[Study of a marker of free radical activity in myocardial infarction and in the prodromal syndrome]

Myocardial ischemia is accompanied by a release of free radicals (FR) derived from oxygen, elements having an important cytotoxic activity. These FR react with unsaturated lipids from the membrane fatty acids, leading possibly to a lysis of the membrane. This lipidic peroxidation of the fatty acids generates, in fact, endoperoxides, unstable lipid by-products and also with a cytotoxic activity. At the end of these reactions, cyclical compound and aldehydes are formed, and it is possible to titrate one of them, the malondialdehyde (MDA) which represents a marker of the aggression of the radicals on the membranes. We have therefore studied the appearance of MDA in the systemic venous blood and compared 10 patients with a threat syndrome (group I) to 8 other patients with acute myocardial infarction (group II). The plasma MDA level is measured upon admission (D1), on the 5th day (D2) and on the 12th day (D3) of the evolution. We have therefore found a significant elevation of MDA in the two groups of patients at D1 and D2, in comparison with the results obtained in a reference group of 15 normal patients (p less than 0.01). In the infarction group, the level of MDA on the 12th day (189 +/- 41 ng/ml) drops significantly as compared to the highest level noted upon admission and on the 5th day, called MDA peak (258 +/- 62 ng/ml, p less than 0.01). The MDA drop is less marked in group I of the threat syndromes.(ABSTRACT TRUNCATED AT 250 WORDS)

[Study of lipid peroxidation by the assay of malondialdehyde in human and experimental atheroma]

Malondialdehyde is a marker for the oxidation of membrane unsaturated fatty acids. This biochemical process, called lipid peroxidation, occurs in the biosynthesis of leukotrienes, prostaglandins and other cytotoxic and chemotactic lipid peroxides. It may play a part in the genesis of atheroma from lipids stored in the arterial wall. Plasma malondialdehyde levels were found to be different in hyperlipidemic subjects with or without arterial lesions, and in rabbits under an atherogenic diet with or without added silicon. The same positive correlation was found in rabbit aorta between atheromatous lesions and high levels of malondialdehyde. These data would support the hypothesis that lipid peroxidation plays a role in atherogenesis.

[Membrane lipid peroxidation in coronary insufficiency]

Malondialdehyde (MDA) as lipid peroxidation marker was studied in 27 patients with acute coronary insufficiency. Significantly elevated plasma levels as compared with controls were found in patients with myocardial necrosis and with preinfarction syndrome. No correlation was found between MDA and creatine phosphokinase, and a significant MDA decrease was observed at day 12: plasma MDA reached normal levels in the myocardial necrosis group. The MDA decrease was also significant in the preinfarction group, but the MDA level remained high in 4 patients with unstable angina. MDA is not a prognostic index. No correlation was found between MDA and plasma lipid levels or patients' ages. These data confirm that myocardial ischemia is associated with abnormal production of oxygen-derived free radicals which react with the membrane unsaturated fatty acids, resulting in toxic endoperoxides. This is thought to be one of the physio-pathological pathways which aggravate ischemic myocardial tissue damage.

[Free radical toxicity in coronary insufficiency]

A number of experimental models have shown abnormally high concentrations of cytotoxic oxygen derived free radicals (FR), and decreased concentrations of protecting anti-oxidising enzymes during myocardial ischaemia. These FR react with the unsaturated lipids of the cell membrane, a phenomenon known as membrane lipidoperoxidation (MLP) to produce very cytotoxic endoperoxides. We studied an intermediary product of MLP, malondialdehyde (MDA) in 10 patients with a preinfarction syndrome (Group 1) and 8 patients in the acute phase of myocardial infarction (Group 2). Plasma MDA was measured on admission (P2) and 12th day (P3). There was a significant elevation of MDA in both groups at P1 and P2 (p less than 0.01) compared with results obtained in 15 normal control subjects of the same age. The MDA concentration on the 12th day in the infarct group was significantly lower (189 +/- 41 ng/ml, p less than 0.01) compared with the highest value observed either on admission or on the 5th day (peak MDA 258 +/- 62 ng/ml). The difference between MDA concentrations on the 12th day and peak MDA was less striking in Group 1. None of the patients in Group 2 had a recurrence of chest pain after the initial phase of infarction and the residuals MDA concentration (P3) was similar to control values (181 +/- 27 ng/ml). On the other hand, in the preinfarction syndrome group, 4 patients had persistent unstable angina on the 12th day and their MDA concentrations remained high (250 +/- 42 ng/ml). This was interpreted as reflecting continuing MLP in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

[Free radicals derived from oxygen and lipid peroxidation. Role in cellular biology and physiopathology]

Lipid peroxidation results from the attack of membrane phospholipids by free radicals derived from oxygen. It plays a major role in normal cell life processes. Under physiological conditions, this attack is modulated by an enzymatic system (superoxide dismutase, catalase, glutathione peroxidase) and by a non-enzymatic system (vitamin E and others). Many pathological processes might be explained by a deficient protection system or by an imbalance between attack and protection. Lipid peroxidation is difficult to detect and measure, and the methods available still have low sensitivity.

Influence of photoperiod on dense-core vesicles and synaptic ribbons of pinealocytes of the djungarian hamster (Phodopus sungorus)

The ultrastructure of the superficial part of the pineal gland of Phodopus sungorus was examined. Dense-core vesicles and synaptic ribbons in pinealocytes of animals kept under different photoperiods were counted, revealing marked differences. Pinealocytes of short-day animals compared with long-day animals exhibit an increase of dense-core vesicles coincident with a decrease of synaptic ribbons. It is assumed that the corresponding numerical changes of these organelles are of functional significance in relation to pineal secretory activity.

Influence of photoperiod on the ultrastructure of the hypophysial pars tuberalis of the Djungarian hamster, Phodopus sungorus

Conspicuous cytological differences are found between specific secretory cells of the hypophysial pars tuberalis of Djungarian hamsters exposed to long and short photoperiods. The cells differ with respect to the shapes of perikarya and nuclei and show diverse amounts of secretory granules, lysosome-like bodies and glycogen.

The management of thirty immunocompromised patients with tuberculosis

Between 1978 and 1981, 30 of 870 bacteriologically confirmed cases of tuberculosis occurred in immunocompromised hosts. One year after the diagnosis, 11 patients were dead, only 2 of them of tuberculosis. In the other 19 patients, the course of tuberculosis under standard chemotherapy was the same as in nonimmunocompromised hosts. Among the 24 patients still alive more than 2 months after the diagnosis of tuberculosis, the treatment of the underlying disease was changed in 14 patients to avoid worsening of the course of tuberculosis; 5 patients died and 4 kidney transplant carriers rejected their transplants. The treatment of the underlying disease was not changed in 10 patients: all of these remained alive 1 yr later, and 2 were kidney transplant carriers who did not reject their transplants. We conclude that the clinical response of the immunocompromised tuberculous host was good and that treatment of the underlying disease should not be modified.

[Calculation of the peak systolic wall stress at the equator of the left ventricle by coupled M mode echo and pressure recordings]

The peak systolic wall stress at the equator of the left ventricle (sigma max) is the maximum load that the myocardial fibres bear during contraction. It is an index of the adaptation of the left ventricle to cardiac disease, and, when elevated, it indicates cardiac decompensation. sigma max was calculated by coupled M mode echo-LV pressure recordings in 51 cases: 11 patients without LV disease, 14 patients with aortic stenosis (AS), 14 patients with aortic incompetence (AI), 7 patients with severe mitral incompetence (MI) and 5 patients with cardiomyopathy with dilatation (CMP). sigma max was calculated from Mirsky's formula, the length of the long axis being deduced from the short axis and the diastolic:systolic ratio of these two axes from ventriculography. The normal value of sigma max by this method is 220 dynes 10(3)/cm2 +/- 30 with an upper limit of normal of 280 dynes 10(3)/cm2. sigma max was normal in patients with AS and AI, and increased in the cases of MI and CMP, in positive correlation with LV volume (r = 0,47) and the shape of the LV (long:short axis ratio). No correlations were found between sigma max and maximum LV pressure. The relatively low values of sigma max compared to the results obtained from coupled echo-angio recordings are partly due to the thick walled LV model and, to a large extent, to the lower values of short axis when measured by echo compared to angiography.(ABSTRACT TRUNCATED AT 250 WORDS)

[Cardiac involvement in systemic lupus erythematosus. 103 cases (author's transl)]

One hundred and three cases of systemic lupus erythematosus (SLE) were reviewed after a period of up to 10 years. The pericardium was involved in 27%, the endocardium in 23% and the myocardium in 14.5% of the cases. Arrhythmia was rare and usually accompanied pericardial or myocardial lesions. Conduction disorders were present in 14.5% of the patients. Atrioventricular block often occurred long after the acute phase of SLE, and synthetic antimalarial drugs appear to be responsible for their development. Whether or not SLE affects the heart, the prognosis is the same during the first ten years of the disease.