Near-infrared fluorescence angiography with indocyanine green for perfusion assessment of DIEP and msTRAM flaps: A Dutch multicenter randomized controlled trial

Background

A common complication after a DIEP flap reconstruction is the occurrence of fat necrosis due to inadequate flap perfusion zones. Intraoperative identification of ischemic zones in the DIEP flap could be optimized using indocyanine green near-infrared fluorescence angiography (ICG-NIR-FA). This randomized controlled trial aims to determine whether intraoperative ICG-NIR-FA for the assessment of DIEP flap perfusion decreases the occurrence of fat necrosis.

Design/methods

This article describes the protocol of a Dutch multicenter randomized controlled clinical trial: the FAFI-trial. Females who are electively scheduled for autologous breast reconstruction using DIEP or muscle-sparing transverse rectus abdominis muscle (msTRAM) flaps are included. A total of 280 patients will be included in a 1:1 ratio between both study arms. In the intervention arm, the intraoperative assessment of flap perfusion will be based on both regular clinical parameters and ICG-NIR-FA. The control arm consists of flap perfusion evaluation only through the regular clinical parameters, while ICG-NIR-FA images are obtained during surgery for which the surgeon is blinded. The main study endpoint is the difference in percentage of clinically relevant fat necrosis between both study arms, evaluated two weeks and three months after reconstruction.

Conclusion

The FAFI-trial, a Dutch multicenter randomized controlled clinical trial, aims to investigate the clinical added value of intraoperative use of standardized ICG-NIR-FA for assessment of DIEP/msTRAM flap perfusion in the reduction of fat necrosis.

Clinical trial registration number

NCT05507710; NL 68623.058.18.

Nelfinavir and lenalidomide/dexamethasone in patients with lenalidomide-refractory multiple myeloma. A phase I/II Trial (SAKK 39/10)

The antiretroviral agent nelfinavir has antimyeloma activity and can overcome resistance to bortezomib. Our phase I/II trial investigated whether adding nelfinavir to lenalidomide-dexamethasone can overcome lenalidomide resistance in lenalidomide-refractory multiple myeloma (MM). Twenty-nine patients were included (high-risk cytogenetic aberrations 31%; ≥2 prior therapy lines 93%; lenalidomide-bortezomib double-refractory 34%). Twenty-four patients (83%) had prior bortezomib and 10 (34%) were lenalidomide-bortezomib double-refractory. They received four cycles of nelfinavir 2500 mg/day with standard-dose lenalidomide (25 mg days 1-21) and dexamethasone (40/20 mg days 1, 8, 15, 22). Minor response or better was achieved in 16 patients (55%; 95% CI 36-74%), including 40% of those who were lenalidomide-bortezomib double-refractory, and partial response or better in nine patients (31%; 95% CI 15-51%). Median progression-free survival was 3.4 (95% CI 2.0-4.9) months and median overall survival 21.6 (13.0-50.1) months. Lenalidomide-related pneumonitis, pneumonia, and neutropenic fever occurred, but there were no unexpected adverse events. Peripheral blood mononuclear cells showed a 45% (95% CI 40-51%) reduction in total proteasome activity from baseline and significant induction of unfolded protein response and autophagy. Thus, nelfinavir-lenalidomide-dexamethasone is an active oral combination in lenalidomide-refractory MM.

Prevention, monitoring and treatment of cardiovascular adverse events in myeloma patients receiving carfilzomib A consensus paper by the European Myeloma Network and the Italian Society of Arterial Hypertension

BACKGROUND

The novel proteasome inhibitor carfilzomib alone or in combination with other agents is already one of the standard therapies for relapsed and/or refractory multiple myeloma (MM) patients and produces impressive response rates in newly diagnosed MM as well. However, carfilzomib-related cardiovascular adverse events (CVAEs) - including hypertension (all grades: 12.2%; grade ≥3: 4.3%), heart failure (all grades: 4.1%; grade ≥3: 2.5%) and ischemic heart disease (all grades: 1.8%; grade ≥3: 0.8%) - may lead to treatment suspensions. At present, there are neither prospective studies nor expert consensus on the prevention, monitoring and treatment of CVAEs in myeloma patients treated with carfilzomib.

METHODS

An expert panel of the European Myeloma Network in collaboration with the Italian Society of Arterial Hypertension and with the endorsement of the European Hematology Association aimed to provide recommendations to support health professionals in selecting the best management strategies for patients, considering the impact on outcome and the risk-benefit ratio of diagnostic and therapeutic tools, thereby achieving myeloma response with novel combination approaches whilst preventing CVAEs.

RESULTS

Patients scheduled to receive carfilzomib need a careful cardiovascular evaluation before treatment and an accurate follow-up during treatment.

CONCLUSIONS

A detailed clinical assessment before starting carfilzomib treatment is essential to identify patients at risk for CVAEs, and accurate monitoring of blood pressure and of early signs and symptoms suggestive of cardiac dysfunction remains pivotal to safely administer carfilzomib without treatment interruptions or dose reductions.

Prevention and management of adverse events of Novel agents in multiple myeloma: A consensus of the european myeloma network

During the last few years, several new drugs have been introduced for treatment of patients with multiple myeloma, which have significantly improved treatment outcome. All of these novel substances differ at least in part in their mode of action from similar drugs of the same drug class, or are representatives of new drugs classes, and as such present with very specific side effect profiles. In this review, we summarize these adverse events, provide information on their prevention, and give practical guidance for monitoring of patients and for management of adverse events.Leukemia accepted article preview online, 18 December 2017. doi:10.1038/leu.2017.353.

Carfilzomib resistance due to ABCB1/MDR1 overexpression is overcome by nelfinavir and lopinavir in multiple myeloma

Proteasome inhibitor (PI) carfilzomib (CFZ) has activity superior to bortezomib (BTZ) and is increasingly incorporated in multiple myeloma (MM) frontline therapy and relapsed settings. Most MM patients ultimately experience PI-refractory disease, an unmet medical need with poorly understood biology and dismal outcome. Pharmacologic targeting of ABCB1 improved patient outcomes, including MM, but suffered from adverse drug effects and insufficient plasma concentrations. Proteomics analysis identified ABCB1 overexpression as the most significant change in CFZ-resistant MM cells. We addressed the functional role of ABCB1 overexpression in MM and observed significantly upregulated ABCB1 in peripheral blood malignant plasma cells (PCs) vs untreated patients' bone marrow PC. ABCB1 overexpression reduces the proteasome-inhibiting activity of CFZ due to drug efflux, in contrast to BTZ. Likewise, the cytotoxicity of established anti-MM drugs was significantly reduced in ABCB1-expressing MM cells. In search for potential drugs targeting ABCB1 in clinical trials, we identified the HIV protease inhibitors nelfinavir (NFV) and lopinavir (LPV) as potent functional modulators of ABCB1-mediated drug export, most likely via modulation of mitochondria permeability transition pore. NFV and LPV restored CFZ activity at therapeutically relevant drug levels and thus represent ready-to-use drugs to be tested in clinical trials to target ABCB1 and to re-sensitize PC to established myeloma drugs, in particular CFZ.

Nelfinavir augments proteasome inhibition by bortezomib in myeloma cells and overcomes bortezomib and carfilzomib resistance

HIV protease inhibitors (HIV-PI) are oral drugs for HIV treatment. HIV-PI have antitumor activity via induction of ER-stress, inhibition of phospho-AKT (p-AKT) and the proteasome, suggesting antimyeloma activity. We characterize the effects of all approved HIV-PI on myeloma cells. HIV-PI were compared regarding cytotoxicity, proteasome activity, ER-stress induction and AKT phosphorylation using myeloma cells in vitro. Nelfinavir is the HIV-PI with highest cytotoxic activity against primary myeloma cells and with an IC₅₀ near therapeutic drug blood levels (8–14 μM), irrespective of bortezomib sensitivity. Only nelfinavir inhibited intracellular proteasome activity in situ at drug concentrations <40 μℳ. Ritonavir, saquinavir and lopinavir inhibited p-AKT comparable to nelfinavir, and showed similar synergistic cytotoxicity with bortezomib against bortezomib-sensitive cells. Nelfinavir had superior synergistic activity with bortezomib/carfilzomib in particular against bortezomib/carfilzomib-resistant myeloma cells. It inhibited not only the proteasomal β1/β5 active sites, similar to bortezomib/carfilzomib, but in addition the β2 proteasome activity not targeted by bortezomib/carfilzomib. Additional inhibition of β2 proteasome activity is known to sensitize cells for bortezomib and carfilzomib. Nelfinavir has unique proteasome inhibiting activity in particular on the bortezomib/carfilzomib-insensitive tryptic (β2) proteasome activity in intact myeloma cells, and is active against bortezomib/carfilzomib-resistant myeloma cells in vitro.

Splenic size after division of the short gastric vessels in Nissen fundoplication in children

PURPOSE

Nissen fundoplication is an effective treatment for gastro-esophageal reflux disease (GERD). Mobilization of the gastric fundus during fundoplication requires division of short gastric vessels of the spleen, which may cause splenic ischemia. The aim of this study was to determine if Nissen fundoplication results in hypotrophy of the spleen.

METHODS

We performed pre-operative and post-operative ultrasound measurements of the spleen in children undergoing Nissen fundoplication. During operation, the surgeon estimated the compromised blood flow by assessment of the percentage of discoloration of the spleen.

RESULTS

Twenty-four consecutive children were analyzed. Discoloration of the upper pole of the spleen was observed in 11 patients (48%) of a median estimated splenic surface of 20% (range 5-50%). The median ratio for pre-operative and post-operative length, width, and area of the spleen was 0.97, 1.03, and 0.96, respectively. The percentage of the estimated perfusion defect during surgery was not correlated with the ratios. In three patients, the area ratio was smaller than 0.8 (0.67-0.75), meaning that the area decreased with at least 20% after surgery. In none of these patients a discoloration was observed.

CONCLUSION

Discoloration of the spleen after Nissen fundoplication is not associated with post-operative splenic atrophy.

The population structure of Staphylococcus aureus among general practice patients from The Netherlands

To investigate the prevalence, the antibiotic resistance pattern and the population structure of Staphylococcus aureus, S. aureus isolates from the anterior nostrils of patients of general practitioners (GPs) were analysed. Insight into the S. aureus population structure is essential, as nasal carriers of S. aureus are at increased risk of developing an S. aureus infection. S. aureus was isolated from nasal swabs from 2691 patients with no sign of an infection collected in 29 GP practices in The Netherlands. The susceptibility pattern for several classes of antibiotics was determined, as well as the S. aureus genetic background, using spa typing. S. aureus was isolated from 617 of the 2691 (23%) nasal swabs. The prevalences of resistance to ciprofloxacin, co-trimoxazole, fusidic acid, macrolides and mupirocin were 0.2%, 0%, 6%, 5% and 1%, respectively. Half of the isolates were associated with a genetic background common to the major methicillin-resistant S. aureus (MRSA) clones, e.g. clonal complex (CC)1, CC5, CC8, CC22, CC30 and CC45, and the remainder were mainly associated with CC7, CC12, CC15, CC26, CC51 and CC101. The low prevalences of resistance suggest that, in the Dutch situation, S. aureus isolates from patients visiting their GP because of complaints not related to infection do not represent a large reservoir of antibiotic resistance genes. Although no MRSA isolates were found, the genetic background of some of the S. aureus isolates is commonly observed among community-associated (CA)-MRSA clones (CC1, CC8 and CC30), and this might suggest that these isolates have the potential to become CA-MRSA.

Hyperattenuating bone marrow abnormalities in myeloma patients using whole-body non-enhanced low-dose MDCT: correlation with haematological parameters

We aimed to establish the role of hyperattenuating medullary abnormalities detected by whole-body non-enhanced low-dose multidetector CT (WBLD-MDCT) in multiple myeloma (MM) patients referred for primary evaluation. 50 consecutive patients with untreated Stage I (n(I) = 11), Stage II (n(II) = 10) and Stage III (n(III) = 29) MM underwent WBLD-MDCT for staging. The number and size of osteolysis, as well as haematologic parameters including paraprotein and beta2-microglobulin levels, were assessed and related to the number, size and density of medullary abnormalities assumed to represent myeloma involvement. Bone marrow abnormalities were found in 2/11 (18%) Stage I, 6/10 (60%) Stage II and 20/29 (69%) Stage III myeloma patients, and did not parallel the incidence of osteolysis. Patients with medullary lesions had higher levels of immunoglobulin A (median, 4730 mg dl(-1) vs 1520 mg dl(-1)), light-chain proteinuria (median, 690 mg dl(-1) vs 214 mg dl(-1)) and IgG paraprotein (median, 3270 mg dl(-1) vs 2610 mg dl(-1)) compared with patients without medullary lesions. In patients with medullary abnormalities, levels of serum beta2-microglobulin were significantly higher than in patients without detectable marrow infiltrates (median, 4.3 mg dl(-1) vs 2.4 mg dl(-1); p = 0.0015). In conclusion, medullary abnormalities visualized by WBLD-MDCT are encountered in all stages of myeloma, including cases without osteolysis. They are associated with significantly elevated serum levels of paraprotein (reflecting tumour mass) and beta2-microglobulin, a prospective prognostic marker for myeloma. The nature and possible prognostic significance of medullary abnormalities detected by WBLD-MDCT therefore warrants further investigation.

Activity patterns of proteasome subunits reflect bortezomib sensitivity of hematologic malignancies and are variable in primary human leukemia cells

Proteasomal proteolysis relies on the activity of six catalytically active proteasomal subunits (beta1, beta2, beta5, beta1i, beta2i and beta5i). Applying a functional proteomics approach, we used a recently developed activity-based, cell-permeable proteasome-specific probe that for the first time allows differential visualization of individual active proteasomal subunits in intact primary cells. In primary leukemia samples, we observed remarkable variability in the amounts of active beta1/1i-, beta2/2i- and beta5/5i-type of subunits, contrasting with their constant protein expression. Bortezomib inhibited beta5- and beta1-type, but to a lesser extend beta2-type of subunits in live primary cells in vitro and in vivo. When we adapted the bortezomib-sensitive human acute myeloid leukemia cell line HL-60 to bortezomib 40 nM (HL-60a), proteasomal activity profiling revealed an upregulation of active subunits, and residual beta1/beta5-type of activity could be visualized in the presence of bortezomib 20 nM, in contrast to control cells. In a panel of cell lines from hematologic malignancies, the ratio between beta2-type and (beta1 + beta5)-type of active proteasomal polypeptides mirrored different degrees of bortezomib sensitivity. We thus conclude that the proteasomal activity profile varies in primary leukemia cells, and that the pattern of proteasomal subunit activity influences the sensitivity of hematologic malignancies toward bortezomib.

The HIV protease inhibitor ritonavir and the proteasome inhibitor bortezomib induce synergistic cytotoxicity on soft tissue sarcoma cells in vitro

9566

Background: HIV-protease inhibitors like Ritonavir produces regressions in HIV-associated Kaposi‘s sarcoma, reportedly due to proteasome inhibition. We have here assessed the effect of Ritonavir and the proteasome inhibitor Bortezomib on the viability and proteasome activity of the soft tissue sarcoma cell lines RD (rhabdomyosarcoma) and A-673 (ewing‘s sarcoma) in vitro. Methods: Cytotoxixity was assessed by MTS-test. To directly dissect proteasome activity in viable sarcoma cells, we used a recently developed cell-permeable affinity label that for the first time allows to assess the individual activity profile of the different catalytically active proteasomal subunits in living cells (Berkers et al., Nature Methods, May 2005). Results: Both types of cells were resistant towards Bortezomib and Ritonavir monotherapy at therapeutic concentrations (20 nM for Bortezomib, 20μM for Ritonavir). Ritonavir induced cytotoxicity in sarcoma cell lines with an IC50 of 40μM. The combination of clinically meaningful concentrations of Ritonavir (20μM) with Bortezomib (10–20 nM) induced robust synergistic cytotoxicity in both sarcoma cell lines. Using affinity labelling of proteasome activity, we directly demonstrate that a) Botezomib abrogates beta5, but also beta1-proteosomal activity in sarcoma cells and b) that Ritonavir at 20μM does not affect proteasom activity. Conclusions: We here present the first analysis of active proteasomal subunits in living human sarcoma cell lines. Ritonavir and Velcade induce synergistic cytotoxicity at clinically meaningful concentrations in vitro, which is not mediated through a direct effect of Ritonavir on proteasome activity. Based on our data, the synergistic combination of Ritonavir and Bortezomib might warrant further clinical testing in soft tissue sarcoma in vivo.

No significant financial relationships to disclose.

The benefit of whole-body low-dose unenhanced multidetector computer tomography (WBLD-MDCT) for follow up and therapy response monitoring in patients with multiple myeloma: Correlation with hematologic parameters

7607

Background: To assessthe value of whole-body low-dose multidetector computer tomography (WBLD-MDCT) as diagnostic and survey modality in multiple myeloma (MM), and as a one-stop alternative (Horger et al. EJR 2005;54:289–297) to established imaging techniques (e.g. x-ray and MRI). Methods: Between 7/2001 and 2/2005, WBLD-MDCT scans were obtained in 90 consecutive patients with histologically proven stage II-III MM, all patients having 2 or more scans (mean = 3,8; range = 2–6). CT-scans were performed using a standardized low-dose protocol and the number, size and density of focal or diffuse medullary (in the appendicular skeleton and pelvis) and extra-medullary lesions as well as osteolysis were analysed for each examination and at follow up. Results were correlated with current standard MM laboratory data and at follow up in order to assess correct temporal recognition of significant myeloma changes by both methods. Results: Detection and follow up of medullary and extra-medullary MM lesions and osteolysis by WBLD-MDCT resulted in a sensitivity of 92%, a specificity of 93%, a NPV of 95%, a PPV of 85% and a likelihood ratio for patients with CT-abnormalities to present changes in the course of their disease of 12. Results of radiologic and hematologic analysis showed high agreement at follow up (median, 3 mo). However, agreement of both techniques at the time of investigation was only moderate (κ = 0.629), with CT being correct in 60% of mismatching cases. Thus, CT enabled earlier detection of MM changes. WBLD-MDCT assessed correctly the course of disease in all 4 patients with nonsecretory MM. Evaluation of stability was optimal in all patients. Conclusions: WBLD-MD represents a reliable, widespread, quick (75s acquisition time), and cost-effective imaging technique in MM, allowing detection of bone marrow involvement, extra-medullary tumors and lytic bone lesions in different clinical settings (staging, follow up, therapy monitoring, evaluation of stability). WBLD-MDCT repeatedly allowed detection of changes in the course of the disease prior to laboratory data, especially in extramedullary MM relapse and nonsecretory MM.

No significant financial relationships to disclose.

Biotinylated fluorescent peptide substrates for the sensitive and specific determination of cathepsin D activity

Cathepsin D (CatD) is a member of the mammalian aspartic protease family and is involved in cellular protein degradation and in several pathological processes. A sensitive and specific assay for the determination of CatD activity in biological samples was developed. The peptide amide substrates Amca-EDKPILF downward arrowFRLGK(biotin)-CONH2 (I), Amca-EEKPIC(Acm)F downward arrowFRLGK(biotin)-CONH2 (II) and Amca-EEKPISF downward arrowFRLGK(biotin)-CONH2 (III) contain a CatD cleavage site (F downward arrowF) flanked by a N-terminal Amca-fluorophore (7-amino-4-methylcoumarin-3-acetic acid) and a C-terminal biotin moiety. Substrates II and III proved to be specific substrates containing only one cleavage site for CatD. After cleavage of the Phe-Phe bond by CatD all biotin conjugated peptides were removed with streptavidin-coated magnetic beads. The remaining fluorescent peptides in solution represent the amount of digested substrate. The versatility of this CatD digest and pull down assay was demonstrated by measuring the activity of CatD in different subcellular fractions of human EBV-transformed B cells and human monocytes. The described method based on the designed CatD substrates represents a valuable tool for routine assays.

Antibiotic resistance of faecal Escherichia coli from healthy volunteers from eight developing countries

OBJECTIVES

To determine the prevalence of antibiotic-resistant faecal Escherichia coli from adult volunteers from urban (U) areas in Kenya, Mexico, Peru and the Philippines, and non-urban (NU) locations in Curacao, Mexico, Venezuela, Ghana, Zimbabwe and the Philippines.

METHODS

Faecal samples of adult volunteers (n=1290) were analysed in one laboratory for the presence of antimicrobial-resistant E. coli using Eosin Methylene Blue agar plates containing, respectively, ampicillin, oxytetracycline, cefazolin, ciprofloxacin, gentamicin, chloramphenicol and trimethoprim at breakpoint concentrations.

RESULTS

The mean age of the volunteers was approximately 35 years; most of them were female. Ciprofloxacin resistance was in the range 1%-63%: the highest percentages were found in the urban populations of Asia and South America. In Peru and the Philippines (U and NU), the prevalence of gentamicin resistance was >20%. Cefazolin resistance was the highest in the urban Philippines (25%). Higher prevalences for ampicillin, oxytetracycline and trimethoprim were found for urban areas compared with non-urban ones of Asia, Africa and South America, respectively (P<0.05).

CONCLUSIONS

In the populations studied, antibiotic resistance in faecal E. coli from adult volunteers was emerging for cefazolin, gentamicin and ciprofloxacin and was high for the older drugs ampicillin, oxytetracycline, trimethoprim and chloramphenicol.

Influence of cefazolin prophylaxis and hospitalization on the prevalence of antibiotic-resistant bacteria in the faecal flora

Faecal samples from 180 patients on admission and 108 patients at discharge were analysed for the prevalence and degree of resistance of Escherichia coli and enterococci. Discharged patients had received 24 h cefazolin prophylaxis and had a mean hospital stay of 10 +/- 5 days. The prevalence of resistance of E. coli to amoxicillin (P < 0.05), cefazolin (P < 0.05) and oxytetracycline was higher for patients at discharge (41, 12 and 35%) than for patients at admission (28, 2 and 27%). The prevalence at discharge was higher after short-term (< or =7 days) than after long-term (>7 days) hospitalization, being significant for amoxicillin only (P < 0.05). No significant changes were observed for the enterococci.

Cathepsin S and an asparagine-specific endoprotease dominate the proteolytic processing of human myelin basic protein in vitro

The biochemical characterization of antigen degradation is an important basis for a better understanding of both the immune response and autoimmune diseases mediated by MHC class II molecules. In this study we used high-performance liquid chromatography and mass spectrometry to analyze the processing of myelin basic protein (MBP), a potential autoantigen implicated in the pathogenesis of multiple sclerosis. We resolved the kinetics of MBP processing by lysosomal extracts or purified endocytic proteases, identified the major cleavage sites during this process and assigned them to the activity of proteolytic enzymes. Proteolytic processing of MBP is mostly guided along the hydrophobic regions of the protein. It is initiated by two proteolytic steps (after N(92) and S(110)) that are performed by an asparagine-specific endopeptidase (AEP) and by cathepsin (Cat) S, respectively. The resulting processing intermediates are converted into more than 60 different species of 20-40-mers due to the activity of endopeptidases including CatS, D and L. The fragments thus generated are subsequently degraded by C- or N-terminal trimming. Strikingly, the initial cleavages during MBP processing affect two immunodominant regions of the potential autoantigen [MBP(85-99) and MBP(111-129)] in an inverse manner. CatS directly generates the N terminus of the epitope MBP(111-129) in large quantities during the initial phase of processing, which might explain the immunogenicity of this region in spite of its relatively poor binding to HLA-DR4. In contrast, the dominant cleavage by AEP mediates the destruction of MBP(85-99) unless the epitope is protected, e.g. by binding to HLA-DR. Our results thus characterize the proteolytic events during processing of MBP on a molecular level and suggest a biochemical basis for the immunogenicity of the immunodominant epitopes, which could serve as a guideline for future therapeutic strategies.

Regulation of CD1 function and NK1.1(+) T cell selection and maturation by cathepsin S

NK1.1(+) T cells develop and function through interactions with cell surface CD1 complexes. In I-A(b) mice lacking the invariant chain (Ii) processing enzyme, cathepsin S, NK1.1(+) T cell selection and function are impaired. In vitro, thymic dendritic cells (DCs) from cathepsin S(-/-) mice exhibit defective presentation of the CD1-restricted antigen, alpha-galactosylceramide (alpha-GalCer). CD1 dysfunction is secondary to defective trafficking of CD1, which colocalizes with Ii fragments and accumulates within endocytic compartments of cathepsin S(-/-) DCs. I-A(k), cathepsin S(-/-) mice do not accumulate class II-associated Ii fragments and accordingly do not display CD1 abnormalities. Thus, function of CD1 is critically linked to processing of Ii, revealing MHC class II haplotype and cathepsin S activity as regulators of NK T cells.

Antibiotic resistance of faecal Escherichia coli in poultry, poultry farmers and poultry slaughterers

The percentage of faecal samples containing resistant Echerichia coli and the proportion of resistant faecal E. coli were determined in three poultry populations: broilers and turkeys commonly given antibiotics, and laying hens treated with antibiotics relatively infrequently. Faecal samples of five human populations were also examined: turkey farmers, broiler farmers, laying-hen farmers, broiler slaughterers and turkey slaughterers. The MICs of antibiotics commonly used in poultry medicine were also determined. Ciprofloxacin-resistant isolates from these eight populations and from turkey meat were genotyped by pulsed-field gel electrophoresis (PFGE) after SmaI digestion. The proportion of samples containing resistant E. coli and the percentages of resistant E. coli were significantly higher in turkeys and broilers than in the laying-hen population. Resistance to nearly all antibiotics in faecal E. coli of turkey and broiler farmers, and of turkey and broiler slaughterers, was higher than in laying-hen farmers. Multiresistant isolates were common in turkey and broiler farmers but absent in laying-hen farmers. The same resistance patterns were found in turkeys, turkey farmers and turkey slaughterers and in broiler, broiler farmers and broiler slaughterers. The PFGE patterns of the isolates from the eight populations were quite heterogeneous, but E. coli with an identical PFGE pattern were isolated at two farms from a turkey and the farmer, and also from a broiler and a broiler farmer from different farms. Moreover, three E. coli isolates from turkey meat were identical to faecal isolates from turkeys. The results of this study strongly indicate that transmission of resistant clones and resistance plasmids of E. coli from poultry to humans commonly occurs.

Individual cathepsins degrade immune complexes internalized by antigen-presenting cells via Fcgamma receptors

We have analyzed the intracellular degradation of an immune complex after its FcgammaR-mediated uptake in antigen-presenting cells (APC). Mice that lack the cathepsins (Cat) S, L, B and D allowed us to assess the direct contribution of these individual proteases to the processing events observed. CatS and CatB mediate the bulk of degradation of the Ig-125I-labeled F(ab')2 immune complex delivered via FcgammaR, while CatL and CatD are dispensable. CatS and CatB are involved in independent processing pathways and can substitute in part for each other's absence. The combined ablation of both proteases reduces the rate of degradation observed by > 80 %. CatB is required for the generation of F(ab')23, a predominant degradation intermediate smaller by approximately 3 kDa than the 125I-labeled F(ab')2 itself. In addition, absence of CatB in vivo significantly affects the activity pattern of the remaining cysteine proteases. Thus, we conclude that CatB is a key enzyme for the proper degradation of an immune complex taken up by FcgammaR and for the control of protease activity in the endocytic pathway of APC.

Early endosomal maturation of MHC class II molecules independently of cysteine proteases and H-2DM

Major histocompatibility complex (MHC) class II molecules bind and present to CD4(+) T cells peptides derived from endocytosed antigens. Class II molecules associate in the endoplasmic reticulum with invariant chain (Ii), which (i) mediates the delivery of the class II-Ii complexes into the endocytic compartments where the antigenic peptides are generated; and (ii) blocks the peptide-binding site of the class II molecules until they reach their destination. Once there, Ii must be removed to allow peptide binding. The bulk of Ii-class II complexes reach late endocytic compartments where Ii is eliminated in a reaction in which the cysteine protease cathepsin S and the accessory molecule H-2DM play an essential role. Here, we here show that Ii is also eliminated in early endosomal compartments without the intervention of cysteine proteases or H-2DM. The Ii-free class II molecules generated by this alternative mechanism first bind high molecular weight polypeptides and then mature into peptide-loaded complexes.

Uninfected and cytomegalic endothelial cells in blood during cytomegalovirus infection: effect of acute rejection

After transplantation, human cytomegalovirus (HCMV) infections can cause vascular damage to both the graft and the host. To study a possible relationship between the degree of vascular injury, clinical symptoms of HCMV infection, and transplant rejection, the appearance and numbers of endothelial cells (ECs) in blood of 54 kidney transplant recipients were investigated in a prospective clinical study. Two types of endothelial cells were identified: cytomegalic ECs (CECs) were detected in patients with moderate or high HCMV antigenemia, and uninfected ECs were observed in patients with and without HCMV infection. The incidence of either CECs, ECs, or the combination of both was associated with HCMV-related clinical symptoms (P<.01). Remarkably, the occurrence of rejection episodes before HCMV infection was an important risk factor for the occurrence of ECs in blood (ECs, CECs, or both) during HCMV infection (P<.001).

Proteases involved in MHC class II antigen presentation

Major histocompatibility complex class II antigen presentation requires the participation of lysosomal proteases in two convergent processes. First, the antigens endocytosed by the antigen-presenting cells must be broken down into antigenic peptides. Second, class II molecules are synthesized with their peptide-binding site blocked by invariant chain (Ii), and they acquire the capacity to bind antigens only after Ii has been degraded in the compartments where peptides reside. The study of genetically modified mice deficient in single lysosomal proteases has allowed us to determine their role in these processes. Cathepsins (Cat) B and D, previously considered major players in MHC class II antigen presentation, are dispensable for degradation of Ii and for generation of several antigenic determinants. By contrast, Cat S plays an essential role in removal of Ii in B cells and dendritic cells, whereas Cat L apparently does so in thymic epithelial cells. Accordingly, the absence of Cat S and L have major consequences for the onset of humoral immune responses and for T-cell selection, respectively. It is likely that other as yet uncharacterized lysosomal enzymes also play a role in Ii degradation and in generation of antigenic determinants. Experiments involving drugs that interfere with protein traffic suggest that more than one mechanism for Ii removal, probably involving different proteases, can co-exist in the same antigen-presenting cell. These findings may allow the development of protease inhibitors with possible therapeutic applications.

Enterococci with glycopeptide resistance in turkeys, turkey farmers, turkey slaughterers, and (sub)urban residents in the south of The Netherlands: evidence for transmission of vancomycin resistance from animals to humans?

The number of vancomycin-resistant enterococci (VRE) relative to the total number of enterococci was determined in fecal samples from turkeys and three human populations in 1996, each with a different level of contact with turkeys, i.e., turkey farmers, turkey slaughterers, and (sub)urban residents. The percentage of VRE relative to the total enterococcal population (i.e., the degree of resistance) was low (2 to 4%) in all groups (except in six samples). No difference was observed between farmers who used avoparcin and those who did not. The pulsed-field gel electrophoresis (PFGE) patterns of the VRE isolates from the different populations were quite heterogeneous, but isolates with the same PFGE pattern were found among animal and human isolates, in addition to the isolates which were described previously (A. E. van den Bogaard, L. B. Jensen, and E. E. Stobberingh, N. Engl. J. Med. 337:1558-1559, 1997). Detailed molecular characterization of vanA-containing transposons from different isolates showed, that in addition to a previously reported strain, similar transposons were present in VRE isolates from turkeys and turkey farmers. Moreover, similar VanA elements were found not only in isolates with the same PFGE pattern but also in other strains from both humans and animals.

Gene expression of the natriuretic peptide system in atrial tissue of patients with paroxysmal and persistent atrial fibrillation

INTRODUCTION

Circulating cardiac natriuretic peptides play an important role in maintaining volume homeostasis, especially during conditions affecting hemodynamics. During atrial fibrillation (AF), levels of plasma atrial natriuretic peptide (ANP) becomes elevated. The aim of this study was to gather information about gene expression of the natriuretic peptide system on the atrial level in patients with AF.

METHODS AND RESULTS

Right atrial appendages of 36 patients with either paroxysmal or persistent AF were compared with 36 case matched controls in sinus rhythm for mRNA expression of pro- atrial natriuretic peptide (pro-ANP), pro-brain natriuretic peptide (pro-BNP), and their natriuretic peptide receptor type-A (NPR-A). We investigated patients without (n = 36) and with (n = 36) valvular disease. Persistent AF was associated with higher mRNA expression of pro-BNP (+66%, P = 0.04, in patients without valvular disease, and +69%, P < 0.01, in patients with valvular disease) and lower mRNA expression of NPR-A (-58%, P = 0.02, in patients without valvular disease, and -62 %, P < 0.01, in patients with valvular disease). The mRNA content of pro-ANP was only increased in patients with valvular disease (+12%, P = 0.03). No changes were observed in patients with paroxysmal AF.

CONCLUSION

This study demonstrates that persistent, but not paroxysmal, AF induces alterations in gene expression of pro-BNP and NPR-A on the atrial level. Although AF generally is associated with an increase of plasma ANP level, a change in mRNA content of pro-ANP is only observed in the presence of concomitant valvular disease and is of minor magnitude.

DNA damage induction and tumour cell radiosensitivity: PFGE and halo measurements

PURPOSE

To test whether induction of DNA damage is correlated with tumour-cell radiosensitivity.

MATERIALS AND METHODS

Initial DNA damage caused by X-irradiation was measured in ten human tumour cell lines, which largely differed in radiosensitivity, using either the pulsed-field gel electrophoresis assay or the halo technique.

RESULTS

None of the parameters of DNA damage correlated with any parameter of cellular radiosensitivity. This was not only true when the analysis was performed on all data but also when the analysis was performed after separating the cell lines into radioresistant and sensitive groups. Even when differences in chromosome number, ploidy and cell cycle distribution were taken into account, no significant correlations were obtained.

CONCLUSIONS

Contrary to previous suggestions, differences in the number of double-strand breaks induced or chromatin-related 'presentation' of DNA lesions, measured by pulsed-field gel electrophoresis or halo respectively, are generally not the dominant factors determining tumour-cell radiosensitivity.

Chromatin structure and cellular radiosensitivity: a comparison of two human tumour cell lines

The role of variation in susceptibility to DNA damage induction was studied as a determinant for cellular radiosensitivity. Comparison of the radiosensitive HX142 and radioresistant RT112 cell lines previously revealed higher susceptibility to X-ray-induced DNA damage in the sensitive cell line using non-denaturing elution, but not when using alkaline unwinding. The present data also show that no difference in the amount of initial damage is seen when pulsed-field gel electrophoresis (PFGE) or comet analysis are used for DNA damage assessment. However, using the halo assay or a modified version of PFGE in which the higher DNA architecture remained partially intact, the radiosensitive cells showed steeper dose-response curves for initial DNA damage than the radioresistant cells. Analysis of the protein composition, of DNA-nucleoid structures revealed substantial differences when isolated from HX142 or RT112 cells. From our data, it is concluded that HX142 and RT112 differ in their structural organization of chromatin. As no differences in the kinetics of DNA damage rejoining were found, it is hypothesized that the same amount of lesions have a different impact in the two cell lines in that the 'presentation' of DNA damage alters the ratio of repairable to non-repairable DNA damage.

Stimulation of human peripheral blood mononuclear cells by zinc and related cations

Zinc is an important trace element for immune function. Here, we show that zinc addition in a serum- and lipopolysaccharide-free cell culture system leads to significantly enhanced levels of interleukin 1 beta (IL-1 beta) and tumour necrosis factor alpha (TNF-alpha) and to expression of the corresponding mRNA in human peripheral blood mononuclear cells (PBMC). Structurally related divalent cations like cobalt, nickel, and mercury also partially increase monokine secretion but to a much lower and thus insignificant extent. They fail to induce mRNA of TNF-alpha after 3 h of culture. Therefore, monokine induction is a zinc-specific effect influenced by the physicochemical properties of the ion. Confirmation of the unique significance of zinc for immune function provides a better understanding of the mechanisms of specific zinc-mediated immune modulation.

Influence of serum on zinc, toxic shock syndrome toxin-1, and lipopolysaccharide-induced production of IFN-gamma and IL-1 beta by human mononuclear cells

Measurement of cytokine secretion in vitro is usually performed in culture medium supplemented with human serum. We compared the secretion of interferon-gamma and interleukin-1 beta as a parameter for lymphocyte and monocyte activation in RPMI 1640 medium supplemented with fetal calf or autologous serum in serum-free medium and protein-free medium. Four different stimulatory mechanisms were tested: phytohemagglutinin, toxic shock syndrome toxin-1 (TSST-1), lipopolysaccharide (LPS), and zinc ions. We found that the optimal stimulatory zinc concentration depended on the total protein content of the medium, whereas the monokine levels were dependent on the concentration of transport proteins such as transferrin. Monokine induction by LPS or TSST-1 were each influenced by the protein and serum composition in a specific manner. Our results show that the differing mechanisms of cytokine induction are influenced by the medium and serum composition in a diverse but specific manner. Serum- or protein-free medium are especially suitable after superantigen challenge when LPS activity needs to be ruled out or after activation by agents with only a weak stimulatory capacity.

Zinc regulates cytokine induction by superantigens and lipopolysaccharide

Zinc is known to be greatly involved in the regulation of immune functions. Pharmacological zinc supplementation, leading to serum zinc concentrations of more than 0.025 mM, has often been suggested to improve immune responses. However, the exact influence of elevated zinc level on immune functions has not yet been investigated. We found that zinc level selectively enhances cytokine induction by lipopolysaccharide (LPS) in a concentration-dependent fashion: as little as 0.0125 mM supplemental zinc led to nearly 50% elevated interleukin-1 beta (IL-1 beta) levels both in polymorphonuclear cells (PBMC) and whole-blood cultures. The secretion of interferon-gamma (IFN-gamma) could be increased more than 10-fold by 0.1 mM zinc. This could not be observed during stimulation with phytohaemagglutin (PHA). In contrast, zinc levels concentration-dependently down-regulated monocyte activation caused by the superantigens, staphylococcal enterotoxins A and E (SEA, SEE, more than 90% down-regulation by 0.1 mM zinc), the Mycoplasma arthritidis-derived superantigen (MAS), but not toxic shock syndrome toxin-1 (TSST-1), while T-cell response remained unaffected. This was not the result of chemical degradation of the superantigens. We assume that zinc concentration regulates interactions between SEA, SEE and MAS, but not TSST-1 and their major histocompatibility complex (MHC) class II-binding sites. Our data demonstrate that zinc levels control the secretion of IFN-gamma and monokines after both LPS and superantigen challenge within a clinically relevant range of concentrations. This reveals new perspectives and indications for zinc supplementation and also indicates potential risks of therapeutic application of zinc.

Divergent effects of zinc on different bacterial pathogenic agents

Zinc is essential for immunologic function; therefore, it has been postulated that elevated serum levels of zinc might lead to improved immune responses. However, it is not known whether or how serum zinc levels contribute to a clinically relevant mechanism of immunologic activation. In our studies with human peripheral blood mononuclear cells and whole blood, the zinc level selectively enhanced the biologic activity of endotoxin. The combination of nonstimulatory doses of lipopolysaccharide (LPS) and nonstimulatory concentrations of zinc led to the secretion of large amounts of interleukin (IL)-1 beta. In contrast, zinc levels specifically down-regulated monocyte activation caused by some superantigens, staphylococcal enterotoxin A and E and Mycoplasma arthritidis--derived superantigen, but not toxic shock syndrome toxin-1. This demonstrates that zinc levels control IL-1 beta secretion after both LPS and superantigen challenge within a clinically relevant range of concentrations. Our data suggest that the indications and contraindications for clinical zinc supplementation should be reconsidered.

Induction of cytokines by zinc ions in human peripheral blood mononuclear cells and separated monocytes

Zinc plays an important role in the maintenance of immune functions. The immunological mechanisms triggered by zinc, however, are still poorly understood. In our experiments Zn2+ ions, added as ZnSO4, stimulated PBMC to produce IFN-gamma, IL-1 beta, IL-6, TNF-alpha, and sIL-2R in a concentration-dependent manner. CuSO4 and CaCl2 as cation and anion controls had no effect. The optimal concentration of zinc was 0.5 mM for monokine induction and 0.25 mM for induction of IFN-gamma and sIL-2R. The highest IL-1 beta and IL-6 levels were found on day 2 and maximum TNF-alpha after 16 h. IFN-gamma and sIL-2R production were optimum after 6 and 7 days, respectively. Monokines could be induced in autologous serum as well as in fetal calf serum and serum-free medium. Enriched monocytes and the human monocyte cell line Mono Mac 6 also released IL-1 beta after zinc challenge. Anti-IL-6 reduced IFN-gamma secretion whereas anti-IL-1 beta inhibited it. These data suggest that zinc acts primarily on monocytes by inducing monokine secretion and that T-cell activation represents a secondary effect in the cytokine cascade.

Intravenous or oral adjuvant CMF for node-positive breast cancer

To assess the optimal duration and method of administration of adjuvant cyclophosphamide, methotrexate and 5-fluorouracil (CMF) chemotherapy, 116 patients with positive axillary nodes after total mastectomy and axillary dissection were reviewed retrospectively. CMF was administered in three progressively shorter regimens, which consisted of oral CMF for either 12 or six cycles and intravenous (i.v.) CMF for six cycles. Median follow-up for surviving patients was 62 months. The three groups were matched for major prognostic factors. There was no advantage in using more than six cycles of adjuvant CMF. There was an improved crude 3 year disease-free survival (84 vs 65%, P = 0.05) and a trend towards improved overall survival (92 vs 85%, P = NS) in patients treated with six cycles of oral CMF compared with i.v. CMF. Survival rates were not significantly different beyond 3 years. Leucopenia and alopecia were more severe with oral CMF (P less than 0.01), and compliance worse with oral CMF x 12 (P = 0.01). Since the data suggest that i.v. CMF is at least as equal as oral CMF a randomized controlled trial should be undertaken.