Evaluation of the isoflurane-sparing effects of lidocaine infusion during umbilical surgery in calves

OBJECTIVE: To evaluate the isoflurane-sparing effects of lidocaine administered by constant rate infusion (CRI) during umbilical surgery in calves. STUDY DESIGN: Randomized 'blinded' prospective clinical study. ANIMALS: Thirty calves (mean 4.7 +/- SD 2.5 weeks old) undergoing umbilical surgery. METHODS: After premedication with xylazine (0.1 mg kg(-1) , IM), anaesthesia was induced with ketamine (4 mg kg(-1) , IV) and maintained with isoflurane in O(2) administered through a circle breathing system. The calves were assigned randomly to receive a bolus of 2 mg kg(-1) lidocaine IV after induction of anaesthesia, followed by CRI of 50 mug kg(-1) minute(-1) (group L, n=15) or a bolus and CRI of 0.9% sodium chloride (NaCl, group S, n=15). End-tidal isoflurane was adjusted to achieve adequate depth of anaesthesia. Heart rate, direct arterial blood pressure and body temperature were measured intraoperatively. Groups were compared by t- tests, anova or Mann-Whitney rank sum test as appropriate. RESULTS: The end-tidal concentration of isoflurane (median, IQR) was significantly lower in group L [1.0% (0.94-1.1)] compared to group S [1.2% (1.1-1.5)], indicating a 16.7% reduction in anaesthetic requirement during lidocaine CRI. Cardiopulmonary parameters and recovery times did not differ significantly between groups. CONCLUSION AND CLINICAL RELEVANCE: Lidocaine CRI may be used as a supplement to inhalation anaesthesia during umbilical surgery in calves in countries where such a protocol would be within the legal requirements for veterinary use in food animals. This study did not show any measurable benefit to the calves other than a reduction in isoflurane requirement.

Molecular mechanisms involved in T cell migration across the blood-brain barrier

In the healthy individuum lymphocyte traffic into the central nervous system (CNS) is very low and tightly controlled by the highly specialized blood-brain barrier (BBB). In contrast, under inflammatory conditions of the CNS such as in multiple sclerosis or in its animal model experimental autoimmune encephalomyelitis (EAE) circulating lymphocytes and monocytes/macrophages readily cross the BBB and gain access to the CNS leading to edema, inflammation and demyelination. Interaction of circulating leukocytes with the endothelium of the blood-spinal cord and blood-brain barrier therefore is a critical step in the pathogenesis of inflammatory diseases of the CNS. Leukocyte/endothelial interactions are mediated by adhesion molecules and chemokines and their respective chemokine receptors. We have developed a novel spinal cord window preparation, which enables us to directly visualize CNS white matter microcirculation by intravital fluorescence videomicroscopy. Applying this technique of intravital fluorescence videomicroscopy we could provide direct in vivo evidence that encephalitogenic T cell blasts interact with the spinal cord white matter microvasculature without rolling and that alpha4-integrin mediates the G-protein independent capture and subsequently the G-protein dependent adhesion strengthening of T cell blasts to microvascular VCAM-1. LFA-1 was found to neither mediate the G-protein independent capture nor the G- protein dependent initial adhesion strengthening of encephalitogenic T cell blasts within spinal cord microvessel, but was rather involved in T cell extravasation across the vascular wall into the spinal cord parenchyme. Our observation that G-protein mediated signalling is required to promote adhesion strengthening of encephalitogenic T cells on BBB endothelium in vivo suggested the involvement of chemokines in this process. We found functional expression of the lymphoid chemokines CCL19/ELC and CCL21/SLC in CNS venules surrounded by inflammatory cells in brain and spinal cord sections of mice afflicted with EAE suggesting that the lymphoid chemokines CCL19 and CCL21 besides regulating lymphocyte homing to secondary lymphoid tissue might be involved in T lymphocyte migration into the immuneprivileged CNS during immunosurveillance and chronic inflammation. Here, I summarize our current knowledge on the sequence of traffic signals involved in T lymphocyte recruitment across the healthy and inflamed blood-brain and blood-spinal cord barrier based on our in vitro and in vivo investigations.

Progenitor cell recruitment during individualized high-flow, very-large-volume apheresis for autologous transplantation improves collection efficiency

BACKGROUND: Individual adaptation of processed patient's blood volume (PBV) should reduce number and/or duration of autologous peripheral blood progenitor cell (PBPC) collections. STUDY DESIGN AND METHODS: The durations of leukapheresis procedures were adapted by means of an interim analysis of harvested CD34+ cells to obtain the intended yield of CD34+ within as few and/or short as possible leukapheresis procedures. Absolute efficiency (AE; CD34+/kg body weight) and relative efficiency (RE; total CD34+ yield of single apheresis/total number of preapheresis CD34+) were calculated, assuming an intraapheresis recruitment if RE was greater than 1, and a yield prediction models for adults was generated. RESULTS: A total of 196 adults required a total of 266 PBPC collections. The median AE was 7.99 x 10(6), and the median RE was 1.76. The prediction model for AE showed a satisfactory predictive value for preapheresis CD34+ only. The prediction model for RE also showed a low predictive value (R2 = 0.36). Twenty-eight children underwent 44 PBPC collections. The median AE was 12.13 x 10(6), and the median RE was 1.62. Major complications comprised bleeding episodes related to central venous catheters (n = 4) and severe thrombocytopenia of less than 10 x 10(9) per L (n = 16). CONCLUSION: A CD34+ interim analysis is a suitable tool for individual adaptation of the duration of leukapheresis. During leukapheresis, a substantial recruitment of CD34+ was observed, resulting in a RE of greater than 1 in more than 75 percent of patients. The upper limit of processed PBV showing an intraapheresis CD34+ recruitment is higher than in a standard large-volume leukapheresis. Therefore, a reduction of individually needed PBPC collections by means of a further escalation of the processed PBV seems possible.

High-dose therapy and autologous stem cell transplantation for children with HIV-associated non-Hodgkin lymphoma

In contrast to adults, autologous stem cell transplantation (ASCT) as part of the salvage strategy after high-dose chemo/radiotherapy in human immunodeficiency virus (HIV) related Non-Hodgkin lymphoma (NHL) is not yet established for children. We report on a 13-year patient with congenital HIV infection and refractory Burkitt lymphoma, who was successfully treated by high-dose therapy (HDT) including rituximab followed by ASCT. After 26 months follow-up the patient remains in complete remission and his HIV parameters have normalized with continued highly active antiretroviral therapy (HAART). HIV infection may no longer exclude children from ASCT as part of salvage therapy. Pediatr Blood Cancer (c) 2006 Wiley-Liss, Inc.

In utero haematopoietic stem cell transplantation. Experiences in mice, sheep and humans

Early prenatal diagnosis and in utero therapy of certain fetal diseases have the potential to reduce fetal morbidity and mortality. The intrauterine transplantation of stem cells provides in some instances a therapeutic option before definitive organ failure occurs. Clinical experiences show that certain diseases, such as immune deficiencies or inborn errors of metabolism, can be successfully treated using stem cells derived from bone marrow. However, a remaining problem is the low level of engraftment that can be achieved. Efforts are made in animal models to optimise the graft and study the recipient's microenvironment to increase long-term engraftment levels. Our experiments in mice show similar early homing of allogeneic and xenogeneic stem cells and reasonable early engraftment of allogeneic murine fetal liver cells (17.1% donor cells in peripheral blood 4 weeks after transplantation), whereas xenogeneic HSC are rapidly diminished due to missing self-renewal and low differentiation capacities in the host's microenvironment. Allogeneic murine fetal liver cells have very good long-term engraftment (49.9% donor cells in peripheral blood 16 weeks after transplantation). Compared to the rodents, the sheep model has the advantage of body size and gestation comparable to the human fetus. Here, ultrasound-guided injection techniques significantly decreased fetal loss rates. In contrast to the murine in utero model, the repopulation capacities of allogeneic ovine fetal liver cells are lower (0.112% donor cells in peripheral blood 3 weeks after transplantation). The effect of MHC on engraftment levels seems to be marginal, since no differences could be observed between autologous and allogeneic transplantation (0.117% donor cells vs 0.112% donor cells in peripheral blood 1 to 2 weeks after transplantation). Further research is needed to study optimal timing and graft composition as well as immunological aspects of in utero transplantation.

In utero transplantation of autologous and allogeneic fetal liver stem cells in ovine fetuses

OBJECTIVE: The purpose of this study was to assess the feasibility of autologous stem cell transplantation in fetal sheep and to compare short-term engraftment of allogeneic and autologous fetal liver stem cells in an immunocompetent large animal model. STUDY DESIGN: Fetal liver stem cells were collected from preimmune sheep fetuses with an open or ultrasound-guided technique. After being labeled with PKH26, the cells were transplanted intraperitoneally into allogeneic and autologous fetal recipients at 48 to 64 days of gestation. Engraftment was determined by flow cytometry and real-time polymerase chain reaction 1 to 2 weeks after transplantation. RESULTS: Fetal loss rate was 29% (allogeneic transplantation) and 73% (autologous transplantation). Engraftment of donor cells was found in all fetuses, with a level of < or =4.7% in fetal liver, spleen, bone marrow, blood and thymus. Overall, there was no difference between allogeneic and autologous grafts. CONCLUSION: Autologous in utero transplantation of fetal liver stem cells in fetal sheep is feasible, but yields a high loss rate. Differences in the major histocompatibility complex between donor and recipient seems not to have a major impact on stem cell engraftment early in gestation; major histocompatibility complex-independent donor/host competition might be responsible for low engraftment in immunocompetent recipients.

[Pancreas transplantation as treatment of diabetes mellitus]

Pancreatic transplantation is able to normalize blood glucose metabolism and achieve normoglycemia in a majority of patients with insulin-dependent diabetes mellitus. Hoping that normoglycemia will favorably influence development of late complications of diabetes, an increasing number of pancreas transplantations has been performed over the last years. However, the need for immunosuppressive therapy with its problems and possible complications confines pancreatic transplantation mainly to three groups of patients: patients who undergo kidney transplantation for diabetic nephropathy, patients who have already undergone kidney transplantation for diabetic nephropathy and, rarely, patients with extreme difficulties with metabolic control. The results of pancreatic transplantation have continuously improved over the last decade, and a limited number of controlled studies is providing some evidence of a favorable effect on late complications.

Indocyanine green plasma disappearance rate during the anhepatic phase of orthotopic liver transplantation

Non-invasive pulse spectrophotometry to measure indocyanine green (ICG) elimination correlates well with the conventional invasive ICG clearance test. Nevertheless, the precision of this method remains unclear for any application, including small-for-size liver remnants. We therefore measured ICG plasma disappearance rate (PDR) during the anhepatic phase of orthotopic liver transplantation using pulse spectrophotometry. Measurements were done in 24 patients. The median PDR after exclusion of two outliers and two patients with inconstant signal was 1.55%/min (95% confidence interval [CI]=0.8-2.2). No correlation with patient age, gender, body mass, blood loss, administration of fresh frozen plasma, norepinephrine dose, postoperative albumin (serum), or difference in pre and post transplant body weight was detected. In conclusion, we found an ICG-PDR different from zero in the anhepatic phase, an overestimation that may arise in particular from a redistribution into the interstitial space. If ICG pulse spectrophotometry is used to measure functional hepatic reserve, the verified average difference from zero (1.55%/min) determined in our study needs to be taken into account.

Blood concentration curve of cyclosporine: impact of itraconazole in lung transplant recipients

Although the influence of cytochrome P450 inhibitory drugs on the area under the curve (AUC) of cyclosporine (CsA) has been described, data concerning the impact of these substances on the shape of the blood concentration curve are scarce. By assessment of CsA blood levels before and 1, 2, and 4 hr after oral intake (C0, C1, C2, and C4, respectively) CsA profiling examinations were performed in 20 lung transplant recipients taking 400 mg, 200 mg, and no itraconazole, respectively. The three groups showed comparable results for C0, C2, and AUC(0-12). Greater values were found for Cmax, Cmax-C0, peak-trough fluctuation and rise to Cmax in favor of the non-itraconazole group. Additionally, tmax was shorter in the non-itraconazole group. Comedication with the metabolic inhibitor itraconazole is associated with a flattening of the CsA blood concentration profile in lung transplant recipients. These changes cannot be assessed by isolated C0, C2, or AUC(0-12) values alone.

The role of purinergic signaling in the liver and in transplantation: effects of extracellular nucleotides on hepatic graft vascular injury, rejection and metabolism

Extracellular nucleotides (e.g. ATP, UTP, ADP) are released by activated endothelium, leukocytes and platelets within the injured vasculature and bind specific cell-surface type-2 purinergic (P2) receptors. This process drives vascular inflammation and thrombosis within grafted organs. Importantly, there are also vascular ectonucleotidases i.e. ectoenzymes that hydrolyze extracellular nucleotides in the blood to generate nucleosides (viz. adenosine). Endothelial cell NTPDase1/CD39 has been shown to critically modulate levels of circulating nucleotides. This process tends to limit the activation of platelet and leukocyte expressed P2 receptors and also generates adenosine to reverse inflammatory events. This vascular protective CD39 activity is rapidly inhibited by oxidative reactions, such as is observed with liver ischemia reperfusion injury. In this review, we chiefly address the impact of these signaling cascades following liver transplantation. Interestingly, the hepatic vasculature, hepatocytes and all non-parenchymal cell types express several components co-ordinating the purinergic signaling response. With hepatic and vascular dysfunction, we note heightened P2- expression and alterations in ectonucleotidase expression and function that may predispose to progression of disease. In addition to documented impacts upon the vasculature during engraftment, extracellular nucleotides also have direct influences upon liver function and bile flow (both under physiological and pathological states). We have recently shown that alterations in purinergic signaling mediated by altered CD39 expression have major impacts upon hepatic metabolism, repair mechanisms, regeneration and associated immune responses. Future clinical applications in transplantation might involve new therapeutic modalities using soluble recombinant forms of CD39, altering expression of this ectonucleotidase by drugs and/or using small molecules to inhibit deleterious P2-mediated signaling while augmenting beneficial adenosine-mediated effects within the transplanted liver.

Cord entanglement in monoamniotic twins: 2D and 3D colour Doppler studies

Cord entanglement affects the majority of monoamniotic (MA) twins, accounting for the high proportion of intrauterine deaths of MA twins, and it is often present from early gestation. 3D ultrasound can be used to acquire volume data comprising information on umbilical colour Doppler flow, providing a very graphic depiction of cord entanglement. We have used 2D, "conventional" and a novel 3D display of colour Doppler ultrasound showing cord entanglement.

IL-6 transsignalling modulates the early effector phase of EAE and targets the blood-brain barrier

Interleukin-6 (IL-6) plays a crucial role in the pathogenesis of experimental autoimmune encephalomyelitis (EAE). It exerts its cellular effects by a membrane-bound IL-6 receptor (IL-6R), or, alternatively, by forming a complex with the soluble IL-6R (sIL-6R), a process named IL-6 transsignalling. Here we investigate the role of IL-6 transsignalling in myelin basic protein (MBP)-induced EAE in the Lewis rat. In vivo blockade of IL-6 transsignalling by the injection of a specifically designed gp130-Fc fusion protein significantly delayed the onset of adoptively transferred EAE in comparison to control rats injected with PBS or isotype IgG. Histological evaluation on day 3 after immunization revealed reduced numbers of T cells and macrophages in the lumbar spinal cord of gp130-Fc treated rats. At the same time, blockade of IL-6 transsignalling resulted in a reduced expression of vascular cell adhesion molecule-1 on spinal cord microvessels while experiments in cell culture failed to show a direct effect on the regulation of endothelial adhesion molecules. In experiments including active EAE and T cell culture, inhibition of IL-6 transsignalling mildly increased T cell proliferation, but did not change severity of active MBP-EAE or regulate Th1/Th17 responses. We conclude that IL-6 transsignalling may play a role in autoimmune inflammation of the CNS mainly by regulating early expression of adhesion molecules, possibly via cellular networks at the blood-brain barrier.

Bronchial circulation after experimental lung transplantation: the effect of direct revascularization of a bronchial artery

Direct revascularization of a bronchial artery has been proposed as a measure to alleviate the problem of bronchial ischemia after lung transplantation. To assess the effect of restoration of arterial blood flow to the transplanted bronchus, bronchial mucosal blood flow was measured in a model of modified unilateral lung transplantation in pigs. Laser Doppler velocimetry (LDV) and radioisotope studies using radio-labeled erythrocytes (RI) were used to measure blood flow at the donor main carina (DC) and upper lobe carina (DUC) after 3 h of reperfusion. The recipient carina was used as a reference point; values obtained by LDV and RI were expressed as percentage of blood flow at the recipient carina. Two groups of animals were studied. In group 1 (n = 6) standard unilateral transplantation was performed; in group 2 (n = 6) a left bronchial artery was reimplanted into the descending thoracic aorta of the recipient. No differences were observed between the two groups with respect to preoperative or postoperative gas exchange or hemodynamics. In group 1, bronchial blood flow at the DC was 37.6 +/- 2.2% (LDV) and 44.1 +/- 14.8% (RI) of reference blood flow. At the DUC, blood flow was 54.9 +/- 7.7% (LDV) and 61.6 +/- 25.7% (RI) of normal flow. In group 2, blood flow was increased at the DC as measured by LDV (55.3 +/- 17.1%; p less than 0.05) and by RI (60.8 +/- 25.3%; p less than 0.2). A similar increase was found at the DUC (LDV: 81.8 +/- 19.3%; p less than 0.05; RI: 88.6 +/- 31.0%; p less than 0.2). It is concluded that there is a significant gradient of blood flow from intra- to extrapulmonary airways after lung transplantation. Reimplantation of a bronchial artery results in significant improvement of graft bronchial blood flow. Restoration of bronchial perfusion to normal levels, however, cannot be achieved, suggesting a possible defect in the microcirculation of the donor airways.

[Unilateral vs. bilateral lung transplantation in obstructive pulmonary disease]

BACKGROUND: The question whether patients suffering from end-stage emphysema who are candidates for lung transplantation should be treated with a single lung or with a double lung transplantation is still unanswered. METHODS: We reviewed 24 consecutive lung transplant procedures, comparing the results of 6 patients with an unilateral and 17 with a bilateral transplantation. PATIENTS AND RESULTS: After bilateral transplantation the patients showed a trend towards better blood gas exchange with shorter time on ventilator and intensive care compared patients after unilateral procedure. Three-year-actuarial survival was higher in the group after bilateral transplantation (83% versus 67%). There was a continuous improvement in pulmonary function in both groups during the first months after transplantation. Vital capacity and forced exspiratory ventilation therapies during the first second were significantly higher in the bilateral transplant group. CONCLUSION: Both unilateral and bilateral transplantation are feasible for patients with end-stage emphysema. Bilateral transplantation results in better pulmonary reserve capacity and faster rehabilitation.