Ultrafast double-slab regenerative amplifier with combined gain spectra and intracavity dispersion compensation

We report on a diode-pumped double-slab Yb:KYW regenerative amplifier with combined gain spectra and intracavity dispersion compensation. At repetition rates > 20 kHz an average power of up to 5 W after compression was generated, resulting in a maximum pulse energy of 250 µJ. Pulse durations of around 190 fs were achieved by using a GRISM compressor with a transmission efficiency of 90%.

Transport, separation, and accumulation of proteins on supported lipid bilayers

Transport, separation, and accumulation of proteins in their natural environment are central goals in protein biotechnology. Miniaturized assays of supported lipid bilayers (SLBs) have been proposed as promising candidates to realize such technology on a chip, but a modular system for the controlled transport of membrane proteins does not exist. In this letter, we demonstrate that standing surface acoustic waves drive the in-plane redistribution of proteins on planar SLBs over macroscopic distances (3.5 mm). Accumulation of proteins in periodic patterns of about 10-fold protein concentration difference is accomplished and shown to relax into the homogeneous state by diffusion. Different proteins separate in individual fractions from a homogeneous distribution and are transported and accumulated into clusters using beats. The modular planar setup has the potential of integrating other lab-on-a-chip tools, for monitoring the membrane-protein integrity or adding microfluidic features for blood screening or DNA analysis.

Quantum-limited noise performance of a femtosecond all-fiber ytterbium laser

We report on quantum-limited noise performance of a mode-locked ytterbium all-fiber laser. The laser operates at a high normal net dispersion without dispersion compensation. We show that the naïve application of analytical models to such lasers leads to strongly underestimated timing jitter, whereas a numerical simulation is in reasonable agreement with measurements. The measured timing phase noise is found to be essentially limited by quantum noise influences and not by technical noise. Furthermore we show that the phase noise of different comb lines has a quasi-fix point at the center of the optical spectrum and that the jitter is translated into high carrier-envelope offset phase noise with a linewidth of around 3 MHz.

Ultrafast high power Yb:KLuW regenerative amplifier

We report on an high power ultra-short pulse regenerative Yb:KLuW amplifier based on the thin disk concept. A maximum pulse energy of 571 microJ was extracted at a repetition rate of 20 kHz. Compression of the output pulses resulted in a pulse duration of 197 fs assuming a deconvolution factor of 2.16. At a repetition rate of 125 kHz a maximum average power of 17.9 W was measured in front of the compressor.

Sub-100 fs pulses from a low repetition rate Yb-doped fiber laser

We report on a passively mode-locked ytterbium-doped fiber laser with a repetition rate of 1.8 MHz. The laser was hybridly mode-locked via nonlinear polarization evolution and a semiconductor saturable absorber mirror. It generated chirped 3.8 ps long pulses with a pulse energy of 1.0 nJ which could be dechirped to a pulse duration of 93 fs.

Lymphangiogenesis in kidney cancer: expression of VEGF-C, VEGF-D and VEGFR-3 in clear cell and papillary renal cell carcinoma

The vascular endothelial growth factors VEGF-C, VEGF-D and its receptor, VEGFR-3, are overexpressed in different malignancies and associated with lymph node metastasis and poor prognosis. We analysed these factors in clear cell (ccRCC) and papillary (pRCC) renal cell carcinoma (RCC). The results were correlated with various clinicopathological parameters (CPP). We constructed a tissue microarray with tumor samples of 135 (81%) ccRCC and 31 (19%) pRCC. After immunohistochemical staining using polyclonal antibodies for VEGF-C, VEGF-D and VEGFR-3, a semiquantitative analysis was performed to determine the levels of expression. The results were compared between the two subgroups and were correlated with CPP. In the two subgroups the expression of VEGF-C was significantly correlated with that of VEGF-D (p<0.001). There was an increased expression of VEGF-C in 11% of ccRCC and 36% of pRCC (p=0.002). VEGF-D expression was positive by means of analysis in 22% of ccRCC and 42% of pRCC (p=0.039). There was no significant difference regarding the expression of VEGFR-3 between the subgroups (44% ccRCC and 61% pRCC, p=0.11). No correlation was found between the expression of the analysed parameters and CPP (TNM, grading, progression-free survival and overall survival) in either the entire group or in the two subgroups. In summary, ccRCC and pRCC show a different expression pattern of the analysed lymphangiogenic factors. Further studies are necessary to confirm these results and to determine whether the VEGF-C/VEGF-D/VEGFR-3-axis can play a role as a prognostic tool or a target for therapeutic intervention in renal cell carcinoma.

Educational program of organ donation and transplantation at medical school

A favorable attitude of health professionals to organ donation can positively influence the decision of families of potential donors. By increasing health professionals knowledge about donation and transplantation and qualifying them to disseminate information, education has produced a positive response to increase the insufficient number of donors. Educating students early in their careers may become crucial in this setting. In order to supply the necessary information about the process of donation and transplantation, a medical school in association with the Hospital Transplant Coordination Department created an educational program of organ donation and transplantation. This course is intended for medical, biomedical, and nutrition students. The objective of our program is to supply basic knowledge about organ donation and transplantation to students of medicine, nutrition, and biomedicine and to enhance their commitment to this process. Each semester, 50 to 90 students are enrolled in the course, which involves a total of 25 hours. Various aspects are approached such as brain death, donor management, political and legal aspects of donation, and skin, lung, bone marrow, heart, pancreas, liver, and kidney transplantation. Between March 2006 and June 2007, three courses were carried out and 200 students were trained. The students evaluated the course and rated it as excellent, concluding that it contributed to their education. Their attitude toward organ donation and transplantation was strongly positive at the end of the course. This project aims to educate and stimulate students in the process of organ donation and transplantation and should be implemented in other medical schools.

[Reasons for the delayed realisation of pregnancy. Results of a questionnaire among women in childbed in the new (east) and old (west) federal states of Germany in 1998-2000]

BACKGROUND

The number of live births in Germany has decreased by 46.7 % from 1 261 614 in 1960 to 672 675 in 2006. The causes for this are manifold. This study attempts to address the possible causes for the delay of birth in Germany in an east-west comparison.

METHOD

Within the "Kinderwunschstudie" (survey of desired/intended fertility) 5 143 women in childbed have been interviewed between 1998 and 2000. They were asked questions concerning the delay of this particular birth. Only women and their spouses who were born in Germany, respectively, were included into the analysis. Berlin women in childbed were excluded from the analysis due to the problematic east-west classification. The number of analysable cases finally added up to 2 020 cases in East Germany and 2 193 cases in West Germany.

RESULTS

24.4 % of the interviewed women in the East admitted a delay of the last birth compared to 21.2 % of those in the West. There are clear differences concerning the reasons for this delay between the old (west) and the new (east) federal states. 34 % of the east German women agreed that an insecure income situation was the reason for the delayed realisation of the desired pregnancy / birth, whereas it was only 16 % in the west.

CONCLUSION

This survey ("Kinderwunschstudie") in fact indicates differences regarding the reasons for a delay of birth between east and west German women (in childbed). However, it also highlights the generally negative influence of the given social and economic conditions on the number of births and underlines the prospects for an ongoing decrease. As a result, society will in future have to face problems of unknown dimensions.

[Polyhydramnios, prematurity, dystrophy, polyuria, constipation, nephrocalcinosis and renal tumor: presentation of a classic tubulopathy]

BACKGROUND

A diagnostic workup of a renal mass will rarely lead to the diagnosis of a tubulopathy. We would like to stress the importance of taking a detailed history and of evaluating these findings in the context of the clinical symptoms.

CASE REPORT

A 3 year old boy with a renal mass, diagnosed due to urinary tract infection, was referred to exclude renal malignancy. Detailed history revealed polyuria and polydipsia in a child with preterm delivery due to polyhydramnios. These symptoms, together with poor thriving are highly suggestive of a neonatal form of Bartter syndrome. This diagnosis was substantiated by ultrasound findings of nephrocalcinosis and urolithiasis due to hypercalciuria and a renal abscess. Detection of mutations in the KCNJ1-gene confirmed the diagnosis. After unilateral nephrectomy for acute destructive nephritis and under medication with indomethacin and potassium citrate the patient is now thriving well.

CONCLUSION

Renal masses suspicious of malignancy may distract from a hereditary tubulopathy. Typical clinical history and presentation with prematurity, polyhydramnios, polyuria, poor thriving and urolithiasis requires diagnostic evaluation of tubular function since routine laboratory tests and urinary dip stick may be normal. Unrecognized, neonatal Bartter syndrome may lead to severe complications including loss of kidney function.

[New markers for pharmacological targeting in bladder cancer with lymph node metastasis]

PURPOSE

VECF-C, -D and their receptor Flt-4 are associated with lymph node metastasis and a poor prognosis in many tumour entities. We have analysed the expression of these factors in transitional cell carcinoma of the bladder with positive lymph nodes.

MATERIALS AND METHODS

We constructed "tissue microarrays" (TMAs) from bladder cancer specimens (BC-array) and corresponding lymph node metastases (LN-array) of 73 patients, who all underwent radical cystectomy and bilateral lymphadenectomy. After immunohistochemical staining, semiquantitative analysis was performed using polyclonal antibodies for VEGF-C, -D and Flt-4. The results were correlated with various histopathological and clinical variables.

RESULTS

VEGF-C (p = 0.007) and Flt-4 (p = 0.019) were significantly higher expressed in the LN-array compared to the BC-array. In the LN-array VEGF-D correlated with T-(p = 0.013) and N-stage (p = 0.030) Flt-4 correlated with N-stage (p = 0.011) and distant metastasis (p = 0.011) in the BC-array, as well as with T-(p = 0.004) and N-stage (p = 0.014) in the LN-array. Accordingly, in the LN-array VEGF-D positive patients showed both a shorter disease-free survival (p = 0.028) and a poorer overall survival (p = 0.014). Similarly, Flt-4 positive patients had a shorter overall survival (p = 0.033).

CONCLUSIONS

Patients with transitional bladder cancer and lymph node metastasis have a poorer prognosis when they overexpress VEGF-D and Flt-4 in their lymph nodes. Pharmacological targeting of these factors could improve their overall survival.

Analysis of lymphangiogenetic factors in invasive bladder cancer—A tissue microarray analysis

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Introduction: Vascular endothelial growth factors (VEGF) -C, -D and their receptor Flt-4 play an emerging role in lymphangiogenesis of different tumor types. Our aim was to determine the role of VEGF-C, VEGF-D and Flt-4 in invasive transitional cell carcinoma of the bladder. Material and Methods: Archival tumor tissue of 286 patients, who had previously undergone radical cystectomy at our institution, was reviewed and representative tumor blocks were selected for constructing a tissue microarray (TMA). Paraffin sections were assessed immunohistochemically using mono- and polyclonal antibodies against VEGF-C, VEGF-D and Flt-4. Staining results were analysed semiquantitatively and correlated with various clinicopathological factors. Results: Overexpression of VEGF-C, VEGF-D and Flt-4 was found in 24.1%, 37.4% and 46.3% of cases, respectively. While there was no association of VEGF-C to histopathological parameters and clinical outcome, patients with VEGF-D overexpression had higher pathological tumor stages (p=0.021) and regional lymph node metastases (p=0.016). Furthermore, they had significantly worse disease-free survival (p=0.042). Overexpression of Flt-4 was found in the subgroup of G3- and G4-tumors (p=0.001) and correlated with a shorter period of disease- free survival (p=0.033). Conclusion: VEGF-C, VEGF-D and Flt-4 are overexpressed in bladder cancer. VEGF-D predicts higher tumor stages and regional lymph node metastases. It is associated with a worse disease-free survival as well as Flt-4 in the subgroup of high-grade tumors. Further studies should be initiated to evaluate VEGF-D and Flt-4 as potential targets in bladder cancer.

No significant financial relationships to disclose.

[Traumatic pseudoaneurysm of arteria femoralis profunda--the case report]

Authors present the case report of the pseudoaneurysm of deep femoral artery caused by the injury of the vessel wall during the open femur fracture. This fracture was primarly treated by repoisition and stabilization by the external fixator (Rohr system, Synthes GmbH, Switzerland), which was nine days later converted into the intramedullar osteosynthesis by the unreamed nail UFN (Synthes GmbH, Switzerland). The first clinical signs of the pseudoaneurysm occurred several days after the patient had been dismissed. In the clinical picture there dominated the painful swelling of thigh but no perfusion or innervation disorders in the periphery of the extremity were noticed and the finding was concluded as myositis ossificans. Proper diagnosis was set only 6 weeks later on the basis of the ultrasound and angiographic investigations. The situation was then solved by the angiographic embolization of pseudoaneurysm. In the discussion also other opinions from the literature are presented.

Extracellular ATP induces assembly and activation of the myosin light chain phosphatase complex in endothelial cells

OBJECTIVES

Extracellular ATP stabilizes the endothelial barrier and inactivates the contractile machinery of endothelial cells. This inactivation relies on dephosphorylation of the regulatory myosin light chain (MLC) due to an activation of the MLC phosphatase (MLCP). To date, activation and function of MLCP in endothelial cells are only partially understood.

METHODS

Here, the mechanism of extracellular ATP-mediated activation of MLCP was analyzed in human endothelial cells from umbilical veins. Cells were transfected with the endogenous protein phosphatase 1 (PP1)-specific inhibitor-2 (I-2).

RESULTS

Overexpression of I-2 led to inhibition of PP1 activity and abrogation of the ATP-induced dephosphorylation of MLC. This indicates that the PP1 catalytic subunit is the principal phosphatase catalyzing the MLC dephosphorylation induced by extracellular ATP. As demonstrated by immunoprecipitation analysis, extracellular ATP recruits the PP1delta catalytic subunit and the myosin phosphatase targeting subunit (MYPT1) to form a complex. ATP stimulated dephosphorylation of MYPT1 at the inhibitory phosphorylation sites threonine 850 and 696. However, extracellular ATP failed to stimulate MYPT1 dephosphorylation in I-2-overexpressing cells.

CONCLUSIONS

The present study shows for the first time that, in endothelial cells, extracellular ATP causes activation of MLCP through recruitment of PP1delta and MYPT1 into a MLCP holoenzyme complex and PP1-mediated reduction of the inhibitory phosphorylation of MYPT1.

Selektive Retinatherapie

Selective retina therapy (SRT) is currently under evaluation, as a new and very subtle laser method, for the treatment of retinal disorders associated with a degradation of the retinal pigmentary epithelium (RPE). SRT makes it possible to selectively effect the RPE, sparing the adjacent neural retina with the photoreceptors and also the choroid below the RPE. In the best case, the therapy leads to regeneration of the RPE and a long-term metabolic increase at the chorio-retinal junction. In contrast to conventional laser photocoagulation, which is associated with complete thermal necrosis of and around the treated site, absolutely no scotoma occurs in SRT. This paper reviews the methods and mechanisms behind the selective effects of the RPE. In vitro and preclinical results are used to describe the bandwidth of selective effects with respect to different irradiation settings. An optoacoustic technique is introduced to visualize effects that cannot be seen by ophthalmoscopy and to facilitate dosimetry control without recourse to angiography completes the report.

Randomized clinical assay for hepatic grafts preservation with University of Wisconsin or histidine-tryptophan-ketoglutarate solutions in liver transplantation

University of Wisconsin (UW) solution has been the standard for preservation of liver transplantation grafts since 1989. However, some studies demonstrated that histidine-tryptophan-ketoglutarate (HTK) solution is also effective. The purpose of this study was to compare the efficacy of both solutions in liver transplantation. From January 2003 to August 2004 the livers of deceased donors were randomized into HTK and UW groups. The 102 studied patients included 65 (63.7%) in the UW group and 37 (36.3%) in the HTK group. Sex, race, hemodynamic state, use of adrenergic drugs, and presence of steatosis in the donor were similarly distributed in the two groups (P > .05). The mean age of the donors was 38.1 years (SD +/-14.4) in the UW group and 44.6 years (SD +/-14.2) in the HTK cohort (P = .036). Sex, race, age, etiology of the cirrhosis, retransplant, acute liver failure, portal thrombosis, and Child-Pugh and MELD scores in the recipients were similarly distributed in the two recipient samples (P > .05). Among 89 patients who completed 4 months of follow-up, the HTK group included eight cases (25.8%) of biliary complications versus five cases (8.6%) in the UW group (P = .033; OR = 2.0 95% CI = 1.2-3.5). The incidence of graft dysfunction was 2.8% in the HTK group and 9.4% in the UW group (P = .15). In conclusion, UW and HTK solutions were equally effective for the preservation of the hepatic graft. The routine use of HTK solution can reduce the costs of liver transplantation.

Steroid myopathy in patients with acute graft-versus-host disease treated with high-dose steroid therapy

High-dose steroids are the first line of treatment for acute graft-versus-host disease (aGVHD). Steroid myopathy is a debilitating steroid-induced complication that significantly impairs a patient's performance status. To determine the frequency and severity of steroid myopathy and other steroid related complications in patients with acute myeloid leukemia (AML)/myelodysplastic syndrome (MDS) who developed grade >or=2 aGVHD after allogeneic hematopoietic stem cell transplantation (HSCT), we performed a retrospective analysis. Patients were included in the analysis if they had a diagnosis of AML/MDS, underwent an allogeneic HSCT between January 1996 and December 2001 and developed grade >or=2 aGVHD that was treated with 2 mg/kg of methylprednisolone and survived at least 100 days post transplant. A total of 70 patients fulfilled our inclusion criteria. Steroid myopathy was identified in 29 (41%) patients. Steroid myopathy was generally of moderate severity with severe debilitating steroid myopathy seen in only 3% of patients. We concluded that steroid myopathy is a common complication of high-dose steroid therapy after allogeneic HSCT in AML/MDS. Interventions aimed at preventing and treating this complication are warranted and need to be explored in prospective clinical trials.

Evidence for MHC I–restricted CD8+ T-cell–mediated immunopathology in canine masticatory muscle myositis and polymyositis

Masticatory muscle myositis (MMM) is the most common inflammatory myopathy (IM) in dogs, associated with antibodies against myosin. To further elucidate the immunopathogenesis, we investigated muscles of 53 dogs with MMM, 32 dogs with polymyositis (PM), and 4 dogs suffering from both, with regard to the presence and location of CD4(+) and CD8(+)T cells, B cells, macrophages, major histocompatibility complex (MHC) class I and class II antigens, and autoantibodies. CD8(+)T cells were found in MMM (91%) and PM (75%), mostly paralleled (68% and 61%) by enhanced expression of MHC class I antigen on muscle fibers. CD8(+)T cells invading intact and neighboring necrotic muscle fibers were present in MMM (39%) and PM (42%). Dogs with MMM lacking intramuscular (26%) and circulating (36%) autoantibodies also had CD8(+) T-cell infiltrations and muscle-fiber lesions. Since MHC class I antigen and CD8(+) T cells were detected in the presence of CD4(+) T cells, regardless of antimuscular antibodies, we consider MMM and PM in the dog as a CD8(+) T-cell-mediated immunopathological disease that initiates muscle-fiber destruction and leads to production of myosin autoantibodies.

Antigenemia for cytomegalovirus in renal transplantation: choosing a cutoff for the diagnosis criteria in cytomegalovirus disease

Cytomegalovirus (CMV) infection is a frequent complication in transplant recipients, causing a high level of morbidity and mortality. We studied 203 consecutive renal transplant recipients performed between January 2000 and December 2001. Patients underwent weekly measurements of CMV pp65 antigen to assess CMV activity from the 4th to the 12th week posttransplantation. The results were reported as number of cells positive for the pp65 antigen among 10(5) granulocytes. In order to define a best cutoff to diagnose CMV disease with desirable sensitivity and specificity, we used a receiver operator characteristics (ROC) curve. The cutoff of four positive cells corresponded to a sensitivity of 93% and specificity of 60% (AUC = 0.87) for the diagnosis of CMV disease. The chosen cutoff for starting antiviral treatment was 10 cells, since this was associated with a sensitivity of 92% and specificity of 70% (AUC = 0.90). In conclusion, the highly sensitive cutoff points for the diagnosis of antigenemia was four cells and 10 cells for initiation of antiviral therapy.

Reduced serine–16 and threonine–17 phospholamban phosphorylation in stunning of conscious dogs

OBJECTIVE

Cardiac stunning is the consequence of a brief cardiac ischemia. The underlying mechanism is not completely understood.

METHODS

Here we induced cardiac transient ischemia in conscious instrumented dogs by means of an occluder in the left anterior descending coronary artery (LAD). Contractile performance, monitored by ultrasound crystals, was reduced during and after ischemia in the LAD area. For control in the same animals cardiac performance was measured in the area of left circumflex coronary artery (Ramus circumflexus, RCx). In the RCx area, no decline in contractility was noted. Tissue was obtained from stunned LAD area and from control areas (RCx).

RESULTS

Phospholamban phosphorylation on both serine-16 and threonine-17 was reduced in LAD areas compared to RCx areas. Reduced phosphorylation of PLB is known to inhibit cardiac contractility. While phosphorylation of PLB was reduced, the activity of the appropriate protein phosphatases and protein kinases was not different between tissue obtained from LAD or RCx areas.

CONCLUSION

Reduced formation of cAMP might underlie the contractile dysfunction in myocardial stunning.

Sirolimus in combination with tacrolimus and corticosteroids for the treatment of resistant chronic graft-versus-host disease

Chronic graft-versus-host disease (cGVHD) remains a major cause of morbidity and mortality in haematopoietic transplant recipients. Sirolimus is a macrocyclic triene antibiotic with immunosuppressive, antifungal and antitumour properties, that has activity in the prevention and treatment of acute GVHD. We conducted a phase II trial of sirolimus combined with tacrolimus and methylprednisolone in patients with steroid-resistant cGVHD. Thirty-five patients who developed GVHD after day 100 post-transplant were studied. Six patients had a complete response and 16 a partial response with an overall response rate of 63%. Major adverse events related to the combination of tacrolimus and sirolimus were hyperlipidaemia, renal dysfunction and cytopenias. Four patients had thrombotic microangiopathy (TMA) and 27 (77%) had infectious complications. The median survival for the whole group was 15 months. A significantly better outcome was observed in patients with a platelet count > or = 100 x 10(9)/l, as well as in those with true chronic manifestations of GVHD compared to those with acute GVHD beyond day 100. Controlled trials comparing this approach with alternative strategies to determine which can best achieve the goal of GVHD-free survival are warranted.

Clinical Relevance of Low Levels of Preformed Alloantibodies Detected by Flow Cytometry in the First Year Post–Kidney Transplantation

OBJECTIVE

To determine the prevalence of transplants performed with a false-negative cytotoxicity cross-match and to analyze the clinical relevance of alloantibodies (Ab) detected only by flow cytometry (flow).

METHODS

We studied 66 patients undergoing kidney transplantation from a cadaveric donor. All patients had a simultaneous negative T+AHG+DTT and B+DTT. Pretransplant sera were retrospectively analyzed by flow cytometry according to an Emory University protocol: (1) T+ and B-: Ab anti-class I; (2) T- and B+: anti-class II; (3) T+B+: anti-class I + II. Chi-square, Fisher exact, Student t test, and Kaplan Meier analyses were employed with significance assigned at P < or = .05.

RESULTS

The overall incidence of false-negative cytotoxicity was 33.3% (22/66), namely, 6.1% (n = 4) anti-class I; 9.1% (n = 6) anti-class II; and 18.2% (n = 12) anti-class I + II. Primary nonfunctioning grafts occurred in 6.8% (3/44) and 13.6% (3/22) negative and positive flow patients (two anti-class I + II and one class II; P = .39). The incidence of graft loss in the first year was respectively, 13.6% (6/44) and 18.2% (4/22; two anti-class II and two anti-class I + II; P = .72). Compared to flow-negative grafts, creatinine levels were significantly higher among flow-positive patients at 8 and 12 weeks. One-year graft survivals were 86.4% among negative versus 81.8% for the positive group (P = .67).

CONCLUSIONS

We observed that 33% of kidney transplant recipients had low levels of alloantibodies detected only by flow. This single factor was associated with the worst graft function in the first trimester with a suggestion of a higher risk for non-functioning graft.

Immunoglobulin G–Positive in B-Cell Cross-Match Decreases Kidney Allograft Survival

We retrospectively studied all 1149 transplants performed at our center between 1993 and 2003 to determine the incidence and clinical effect of pretransplant B-positive cross-match on kidney graft survival. The patients were divided in two groups: B-negative (n = 1102) and B-positive in current sera (n = 47; 4.1%). AB-positive test was more frequent among regrafted patients (14% vs 3%; P = .00). Demographic data were not different between the groups. The overall rate of graft loss was similar (26% vs 24%, respectively; P = .86). However, early nonsurgical graft losses were more frequent among B-positive patients (46% vs 20%, respectively; P = .04). IgM was the most frequent immunoglobulin in the B-positive group (76% IgM and 24% IgG). There was no significant difference between B-negative and B-positive groups in the 1-, 5-, and 10-year graft survival rates (87% vs 83%, 73% vs 78%, 64% vs 66%, respectively; P = .87). The graft survival was significantly reduced comparing an IgG anti-B cell to the B-negative group (P = .03) as well as IgG compared to IgM (P = .004). In conclusion, only B-positive cross-match due to IgG decreased graft survival. Even though it is an uncommon situation (0.9%), this study stressed the clinical value of the B-cell cross-match as a tool to identify patients with a higher immunological risk.

Off-pump coronary artery bypass grafting does not reduce lymphocyte activation

OBJECTIVE

In this study, we test the hypothesis that off-pump coronary bypass surgery might result in less lymphocyte activation than on-pump coronary surgery. We also study the behavior of lymphocyte activation markers during and after surgery.

BACKGROUND

Coronary artery bypass surgery is known to be associated with changes of inflammatory mediators, immune function, and early phase lymphocyte activation, which could cause postoperative lymphopenia and lymphocyte unresponsiveness.

METHODS

We studied lymphocyte activation response in 28 patients randomized to off-pump (n = 13) or on-pump (n = 15) coronary artery bypass surgery. Expression of CD25, CD26, CD69, and DR on T (CD3+) and B (CD19+) lymphocytes on peripheral blood was assessed through flow cytometry.

RESULTS

The response of T lymphocytes and their activation markers, as well as B lymphocytes and their activation markers, was similar after on- and off-pump surgery. Overall, T lymphocytes decreased to the lowest level 9 h after surgery and tended to increase later. For B lymphocytes, there was early reduction with increase on the 1st postoperative day. There was early activation of CD69+ and late activation of CD25+ on T lymphocytes. For B lymphocytes, there was early activation of CD69+ and late activation of DR+.

CONCLUSIONS

(1) Compared to on-pump cardiopulmonary bypass, off-pump surgery does not reduce lymphocyte activation. (2) Coronary bypass surgery causes the early activation of lymphocytes, as evidenced by the increased expression of lymphocyte activation markers.

Validation of the Extended Simultaneous Kinetics and Ringdown Model by Measurements of the Reaction NH2 + NO

The determination of rate constants for fast chemical reactions from nonexponential cavity ringdown profiles requires a consideration of the interfering laser bandwidth effect that arises if the line width of the ringdown probe laser exceeds the absorption line width of the detected species. The deconvolution of the kinetics and the bandwidth effect can be accomplished with the extended simultaneous kinetics and ringdown (eSKaR) model presented by Guo et al. (Guo, et al. Phys. Chem. Chem. Phys. 2003, 5, 4622). We present a detailed validation of this eSKaR model by a corresponding investigation of the well-known rate constant for the reaction NH2 + NO. Line profiles of the pulsed ringdown probe laser and the NH2 absorption line were determined from forward modeling of experimental ringdown profiles and verified by narrow-bandwidth laser absorption measurements. In addition, the rate constant for the title reaction was evaluated using the eSKaR model and also by means of a conventional pump-probe approach with variable time delays between the photolysis (pump) and ringdown (probe) laser pulses. The resulting room temperature rate constant for the NH2 + NO reaction, k1= (8.5 +/- 1.0) x 10(12) cm(3) mol(-1) s(-1), and the room temperature pressure broadening coefficient of NH2, = 2.27 GHz/bar, measured on the A2A1<-- X2B1 transition at wavelengths around lambda = 597 nm, were found to be in excellent agreement with the available literature data.