Clioquinol and 8-hydroxyquinoline-5-sulfonamide derivatives damage the cell wall of Pythium insidiosum.

AIMS: To evaluate the antimicrobial activity and to determine the pharmacodynamic characteristics of three 8-hydroxyquinoline derivatives (8-HQs) against Pythium insidiosum, the causative agent of pythiosis. METHODS AND RESULTS: Antimicrobial activity was tested by broth microdilution and MTT assays. The antimicrobial mode of action was investigated using sorbitol protection assay, ergosterol binding assay, and scanning electron microscopy. Clioquinol, PH151, and PH153 were active against all isolates, with MIC values ranging from 0.25 to 2 µg ml-1. They also showed a time- and dose-dependent antimicrobial effect, damaging the P. insidiosum cell wall. CONCLUSIONS: Together, these results reinforce the potential of 8-HQs for developing new drugs to treat pythiosis.

Novel experimental setup for megahertz X-ray diffraction in a diamond anvil cell at the High Energy Density (HED) instrument of the European X-ray Free-Electron Laser (EuXFEL).

The high-precision X-ray diffraction setup for work with diamond anvil cells (DACs) in interaction chamber 2 (IC2) of the High Energy Density instrument of the European X-ray Free-Electron Laser is described. This includes beamline optics, sample positioning and detector systems located in the multipurpose vacuum chamber. Concepts for pump-probe X-ray diffraction experiments in the DAC are described and their implementation demonstrated during the First User Community Assisted Commissioning experiment. X-ray heating and diffraction of Bi under pressure, obtained using 20 fs X-ray pulses at 17.8 keV and 2.2 MHz repetition, is illustrated through splitting of diffraction peaks, and interpreted employing finite element modeling of the sample chamber in the DAC.

Antifungal activity and toxicological parameters of 8-hydroxyquinoline-5-sulfonamides using alternative animal models.

AIM: The purpose of this study was to evaluate the antifungal activity and toxicological parameters of 8-hydroxyquinoline derivatives PH151 and PH153 using alternative animal models, to understand their behaviour when subjected to in vivo experiments. METHODS AND RESULTS: We used Toll-deficient Drosophila melanogaster to test the protective effect of compounds against Candida albicans infection. Toxicological parameters were investigated in chicken and zebrafish embryos. PH151 and PH153 showed low toxicity and the treated flies with these compounds had a significantly higher survival rate than untreated flies after 7 days of infection. The compounds did not cause interruption of chicken embryogenesis. Zebrafish embryos exposed to compounds showed dose-dependent toxicity. CONCLUSIONS: The data supported the potential of PH151 and PH153 for the treatment of systemic candidiasis and demonstrated to be appropriate drug candidates for further studies using mammalian models. SIGNIFICANCE AND IMPACT OF THE STUDY: The increased incidence of Candida infections resistant to antifungals currently available requires acceleration of the discovery of new agents with properties of inhibiting this fungal pathogen. In this study, we have described the antifungal potential and toxicity of two 8-hydroxyquinoline derivatives using in vivo alternative models, and the results confirm their potential to be developed as new drug candidates.

Oncological outcome after MRI-based selection for neoadjuvant chemoradiotherapy in the OCUM Rectal Cancer Trial.

BACKGROUND: It is not clear whether all patients with rectal cancer need chemoradiotherapy. A restrictive use of neoadjuvant chemoradiotherapy (nCRT) based on MRI findings for rectal cancer was investigated in this study. METHODS: This prospective multicentre observational study included patients with stage cT2-4 rectal cancer, with any cN and cM0 status. Carcinomas in the middle and lower third that were 1 mm or less from the mesorectal fascia, all cT4 tumours, and all cT3 tumours of the lower third were classified as high risk, and these patients received nCRT followed by total mesorectal excision (TME). All other carcinomas with a minimum distance of more than 1 mm from the mesorectal fascia and those in the upper third were classified as low risk; these patients underwent TME alone (no nCRT). Patients were followed for at least 3 years. Outcomes were the rates of local recurrence, distant metastasis and survival. RESULTS: Among 545 patients included, 428 were treated according to the study protocol: 254 (59·3 per cent) had TME alone and 174 (40·7 per cent) received nCRT and TME. Median follow-up was 60 months. The 3- and 5-year local recurrence rates were 1·3 and 2·7 per cent respectively, with no differences between the two treatment protocols. Patients with disease requiring nCRT had higher 3- and 5-year rates of distant metastasis (17·3 and 24·9 per cent respectively versus 8·9 and 14·4 per cent in patients who had TME alone; P = 0·005) and worse disease-free survival compared with that in patients who did not need nCRT (3- and 5-year rates 76·7 and 66·7 per cent, versus 84·9 and 76·0 per cent in the TME-alone group; P = 0·016). CONCLUSION: Restriction of nCRT to high-risk patients achieved good results.

In Vitro Induction of Human Regulatory T Cells Using Conditions of Low Tryptophan Plus Kynurenines.

Thymic regulatory T cells (tTregs) and induced regulatory T cells (iTregs) suppress murine acute graft-versus-host disease (GVHD). Previously, we demonstrated that the plasmacytoid dendritic cell indoleamine 2,3-dioxygenase (IDO) fosters the in vitro development of human iTregs via tryptophan depletion and kynurenine (Kyn) metabolites. We now show that stimulation of naïve CD4+ T cells in low tryptophan (low Trp) plus Kyn supports human iTreg generation. In vitro, low Trp + Kyn iTregs and tTregs potently suppress T effector cell proliferation equivalently but are phenotypically distinct. Compared with tTregs or T effector cells, bioenergetics profiling reveals that low Trp + Kyn iTregs have increased basal glycolysis and oxidative phosphorylation and use glutaminolysis as an energy source. Low Trp + Kyn iTreg viability was reliant on interleukin (IL)-2 in vitro. Although in vivo IL-2 administration increased low Trp + Kyn iTreg persistence on adoptive transfer into immunodeficient mice given peripheral blood mononuclear cells to induce GVHD, IL-2-supported iTregs did not improve recipient survival. We conclude that low Trp + Kyn create suppressive iTregs that have high metabolic needs that will need to be addressed before clinical translation.

Exosome-associated AAV vector as a robust and convenient neuroscience tool.

Adeno-associated virus (AAV) vectors are showing promise in gene therapy trials and have proven to be extremely efficient biological tools in basic neuroscience research. One major limitation to their widespread use in the neuroscience laboratory is the cost, labor, skill and time-intense purification process of AAV. We have recently shown that AAV can associate with exosomes (exo-AAV) when the vector is isolated from conditioned media of producer cells, and the exo-AAV is more resistant to neutralizing anti-AAV antibodies compared with standard AAV. Here, we demonstrate that simple pelleting of exo-AAV from media via ultracentrifugation results in high-titer vector preparations capable of efficient transduction of central nervous system (CNS) cells after systemic injection in mice. We observed that exo-AAV is more efficient at gene delivery to the brain at low vector doses relative to conventional AAV, even when derived from a serotype that does not normally efficiently cross the blood-brain barrier. Similar cell types were transduced by exo-AAV and conventionally purified vector. Importantly, no cellular toxicity was noted in exo-AAV-transduced cells. We demonstrated the utility and robustness of exo-AAV-mediated gene delivery by detecting direct GFP fluorescence after systemic injection, allowing three-dimensional reconstruction of transduced Purkinje cells in the cerebellum using ex vivo serial two-photon tomography. The ease of isolation combined with the high efficiency of transgene expression in the CNS, may enable the widespread use of exo-AAV as a neuroscience research tool. Furthermore, the ability of exo-AAV to evade neutralizing antibodies while still transducing CNS after peripheral delivery is clinically relevant.

Prognosis of patients with colonic carcinoma before, during and after implementation of complete mesocolic excision.

BACKGROUND: The implementation of complete mesocolic excision (CME) for colonic cancer was accompanied by other important changes, including more patients with early diagnosis by screening and the introduction of adjuvant chemotherapy in patients with stage III disease. The contribution of CME remains unclear. METHODS: In this observational study, data from patients with stage I-III colonic carcinoma were analysed by comparing five time intervals: 1978-1984 (pre-CME), 1985-1994 (CME development), 1995-2002 (CME implementation), 2003-2009 (CME) and 2010-2014 (CME), with a special focus on indicators of process and outcome quality. RESULTS: During the observed periods, the median age of patients increased (from 65 to 67 years), there were more right-sided carcinomas (from 17·0 to 32·4 per cent), more stage I disease (from 14·0 to 27·7 per cent) and fewer patients with regional lymph node metastases (from 42·7 to 32·0 per cent). The proportion of patients with pN0 disease and at least 12 examined regional lymph nodes increased (from 84·8 to 100 per cent) as did the R0 resection rate (from 97·0 to 100 per cent). Overall morbidity increased, whereas the in-hospital mortality rate was stable (range 1·8-3·7 per cent). Use of adjuvant chemotherapy in stage III colonic carcinoma increased from 0 to 79 per cent. The improvement in outcome quality was more evident in stage III than in stage I-II tumours. In stage III, the 5-year locoregional recurrence rate decreased from 14·8 to 4·1 per cent (P = 0·046) and the 5-year cancer-related survival rate increased from 61·7 to 80·9 per cent (P = 0·010). CONCLUSION: With CME, the quality indicators of process and outcome quality improved, especially in stage III colonic carcinoma. Adjuvant chemotherapy in stage III and multidisciplinary approaches in patients with metachronous distant metastases contributed to further outcome improvement.

Reduced Sensitivity to Charge Noise in Semiconductor Spin Qubits via Symmetric Operation.

We demonstrate improved operation of exchange-coupled semiconductor quantum dots by substantially reducing the sensitivity of exchange operations to charge noise. The method involves biasing a double dot symmetrically between the charge-state anticrossings, where the derivative of the exchange energy with respect to gate voltages is minimized. Exchange remains highly tunable by adjusting the tunnel coupling. We find that this method reduces the dephasing effect of charge noise by more than a factor of 5 in comparison to operation near a charge-state anticrossing, increasing the number of observable exchange oscillations in our qubit by a similar factor. Performance also improves with exchange rate, favoring fast quantum operations.

Treatment of perforated colon carcinomas-outcomes of radical surgery.

PURPOSE: When patients present with a perforation of a colon cancer (CC), this situation increases the challenge to treat them properly. The question arises how to deal with these patients adequately, more restrictively or the same way as with elective cases. METHODS: Between January 1995 and December 2009, 52 patients with perforated CC and 1206 nonperforated CC were documented in the Erlangen Registry of Colorectal Carcinomas (ERCRC). All these patients underwent radical resection of the primary including systematic lymph node dissection with CME. The median follow-up period was 68 months. RESULTS: The median age of the patients in the perforated CC group was significantly higher than in the nonperforated CC group (p = 0.010). Significantly, more patients with perforated CC were classified in ASA categories 3 and 4 (p = 0.014). Hartmann procedures were performed significantly more frequently with perforation than with the nonperforated ones (p < 0.001). If an anastomosis was performed, the leakage rate of primary anastomoses did not differ (p = 1.0). Cancer-related survival was significantly lower with perforated cancer (difference 12.8 percentage points) and by 9.6 percentage points for observed survival, if postoperative mortality was excluded. CONCLUSIONS: Perforated CC patients should be treated basically following the same oncologic demands, which are CME for colonic cancer including multivisceral resections, if needed. This strategy can only be performed if high-quality surgery is available, permanently.

[Colorectal Carcinoma in Young Patients - Is Age a Prognostic Factor?]. / Das kolorektale Karzinom (KRK) beim jungen Patienten - ist das Alter ein prognostischer Faktor?

INTRODUCTION: Concerning younger patients with colorectal carcinoma (CRC) controversies still exist regarding outcome. The aim of this study was to evaluate possible differences between patients suffering from CRC at a younger age (< 40 years) and at an age over 40 years. PATIENTS AND METHODS: Data of 51 younger patients (< 40 years) and 2122 older patients (≥ 40 years) were prospectively collected and retrospectively evaluated according to clinical parameters, treatment and prognosis. Patients with a CRC arising from familial adenomatous polyposis, ulcerative colitis or Crohn's disease have been excluded. RESULTS: The younger patients presented significantly more often with mucinous adenocarcinomas (p = 0.033). There were no differences between the groups concerning gender, localisation, elective and emergency surgery, UICC (Union internationale contre le cancer) stages and residual tumour classification. Postoperative therapy - in adjuvant, therapeutic or palliative intent - was applied significantly more often in younger patients, especially in those with colon carcinoma (p = 0.001). After curative resection of colon carcinoma a significantly better observed (5 year rate 94 vs. 76 %; p = 0.024) and disease-free (88 vs. 69 %; p = 0.013) survival were found. This trend was similar in patients with rectal carcinoma (84 vs. 75 % and 72 vs. 65 %) without reaching the level of significance (p = 0.155 and 0.269). Taking into account differences in life expectancy, just minor differences were detected in relative survival (colon carcinoma, 5 year rate 94 vs. 89 %; rectal carcinoma, 84 % both). CONCLUSIONS: The general assumption of a poorer prognosis in younger patients with CRC could not be confirmed. Younger patients have a poorer histological subtype of carcinoma. But this is compensated by the better overall condition, less comorbidities, faster postoperative recovery and an optimally organised post-operative (adjuvant, therapeutic or palliative) therapy. In summary, younger patients have a better observed survival but - considering differences in life expectancy - a similar relative survival.

[Quality of Mesorectal Excision ("Plane of Surgery") - Which Quality Targets are Adequate?]. / Qualität der Mesorektumexzision ("plane of surgery") - Welche Qualitätsziele sind angemessen?

Today, the examination of rectal cancer specimens includes the obligate macroscopic assessment of the quality of mesorectal excision by the pathologist reporting the plane of surgery. The frequency of operations in the muscularis propria plane of surgery (earlier described as incomplete mesorectal excision) is essential. The quality of mesorectal excision is important for the prognosis, especially as local recurrences are observed more frequently after operations in the muscularis propria plane of surgery. For the definition of quality targets, data of 13 studies published between 2006 and 2012, each with more than 100 patients and adequate specialisation and experience of the surgeons (5413 patients), data of the prospective multicentric observation study "Quality Assurance - Rectal Cancer" (at the Institute for Quality Assurance in Operative Medicine at the Otto-von-Guericke University at Magdeburg) from 2005 to 2010 (8044 patients) and data of the Department of Surgery, University Hospital Erlangen, from 1998 to 2011 (991 patients) were analysed. The total incidence of operations in the muscularis propria plane of surgery was 5.0 % (721/14 448). Even with adequate specialisation and experience of the surgeon, the frequency of operations in the muscularis propria plane of surgery is higher in abdominoperineal excisions than in sphincter-preserving surgery (8.4 vs. 2.8 %, p < 0.001). Thus, the quality target for the frequency of operations in the muscularis propria plane should be defined as < 5 % for sphincter-preserving procedures and as < 10 % for abdominoperineal excisions.

Prognostic subdivision of ypT3 rectal tumours according to extension beyond the muscularis propria.

BACKGROUND: The subdivision of T3 in rectal carcinoma according to the depth of invasion into perirectal fat has been recommended in the TNM Supplement since 1993. This study assessed the prognostic impact of this pathological staging in tumours removed after neoadjuvant chemoradiotherapy (ypT3). METHODS: Data from patients with ypT3 rectal carcinoma (less than 12 cm from the anal verge) treated with neoadjuvant chemoradiation and total mesorectal excision were analysed. Tumour category ypT3 was subdivided into ypT3a (5 mm or less) and ypT3b (more than 5 mm), based on histological measurements of maximal tumour invasion beyond the outer border of the muscularis propria. RESULTS: Important differences between ypT3a (81 patients) and ypT3b (43) were found in 5-year rates of locoregional recurrence (7 versus 18 per cent; P = 0·049), distant metastasis (20 versus 41 per cent; P = 0·002), disease-free survival (73 versus 47 per cent; P = 0·001), overall survival (79 versus 74 per cent; P = 0·036) and cancer-related survival (81 versus 74 per cent; P = 0·007). In Cox regression analyses, the ypT3 subclassification was identified as an independent prognostic factor for disease-free (ypT3b: hazard ratio (HR) 2·13, 95 per cent confidence interval 1·16 to 3·89; P = 0·014), observed (ypT3b: HR 2·02, 1·05 to 3·87; P = 0·035) and cancer-related (ypT3b: HR 2·46, 1·20 to 5·04; P = 0·014) survival. Extramural venous invasion was found to be an additional prognostic factor, but the pathological node category after chemoradiotherapy (ypN) did not influence survival. CONCLUSION: In ypT3 rectal carcinomas, the proposed subclassification is superior to ypN in predicting prognosis.

A hundred patients with vertical rectus abdominis myocutaneous (VRAM) flap for pelvic reconstruction after total pelvic exenteration.

PURPOSE: We analysed the outcomes of a series of 100 consecutive patients with anorectal cancer with neoadjuvant radiochemotherapy and abdominoperineal exstirpation or total pelvic exenteration, who received a transpelvic vertical rectus abdominis myocutaneous (VRAM) flap for pelvic, vaginal and/or perineal reconstruction and compare a cohort to patients without VRAM flaps. METHODS: Within a 10-year period (2003-2013) in our institution 924 patients with rectal cancer stage y0 to y IV were surgically treated. Data of those 100 consecutive patients who received a transpelvic VRAM flap were collected and compared to patients without flaps. RESULTS: In 100 consecutive patients with transpelvic VRAM flaps, major donor site complications occurred in 6 %, VRAM-specific perineal wound complications were observed in 11 % of the patients and overall 30-day mortality was 2 %. CONCLUSIONS: The VRAM flap is a reliable and safe method for pelvic reconstruction in patients with advanced disease requiring pelvic exenteration and irradiation, with a relatively low rate of donor and recipient site complications. In this first study, to compare a large number of patients with VRAM flap reconstruction to patients without pelvic VRAM flap reconstruction, a clear advantage of simultaneous pelvic reconstruction is demonstrated.

DNA demethylation and tri-methylation of H3K4 at the TACSTD2 promoter are complementary players for TROP2 regulation in colorectal cancer cells.

TROP2 is a powerful cancer driver in colorectal cancer cells. Divergent epigenetic regulation mechanisms for the corresponding TACSTD2 gene exist such as miRNAs or DNA methylation. However, the role of TACSTD2 promoter hypermethylation in colorectal cancer has not been investigated yet. In this study, TROP2 expression strongly correlated with promoter methylation in different colorectal tumor cell lines. Treatment with 5-Azacytidine, a DNMT1 inhibitor, led to demethylation of the TACSTD2 promoter accompanied by an increase in TROP2 protein expression. TROP2 expression correlated with promoter methylation in vivo in human colon tumor tissue, thereby verifying promoter methylation as an important factor in the regulation of TROP2 expression in colorectal cancer. When performing a ChIP-Seq analysis in HCT116 and HT29 cells, we found that TACSTD2 promoter demethylation was accompanied by tri-methylation of H3K4. In silico analysis of GSE156613 data set confirmed that a higher binding of histone mark H3K4me3 around the TACSTD2 promoter was found in TACSTD2 high expressing tumors of colon cancer patients compared to the corresponding adjacent tumor tissue. Moreover, the link between TROP2 and the H3K4me3 code was even evident in tumors showing high intratumoral heterogeneity for TROP2 staining. Our data provide novel evidence for promoter demethylation and simultaneous gains of the active histone mark H3K4me3 across CpG-rich sequences, both being complementary mechanisms in the transcriptional regulation of TACSTD2 in colon cancer. The functional consequences of TROP2 loss in colorectal cancer needs to be further investigated.

COX-2, TFF1, and Src define better prognosis in young patients with gastric cancer.

BACKGROUND AND OBJECTIVES: Despite its dwindling occurrence, gastric cancer remains a leading cause of cancer related mortality worldwide. Molecular determinants of prognosis that impact survival are being sought out as a means to facilitate rational clinical decision-making and enhance patient management. In this study, we evaluated three molecules implicated in gastric carcinogenesis and demonstrated that the differential expression of cyclooxygenase-2 (COX-2) and the viral oncogene homolog Src proteins could explain the differences in survival observed in patients older and younger than 50 years of age. METHODS: We evaluated 5-year survival in a cohort of 423 gastric cancer patients using chronological age as a variable. Additionally, we assessed the protein expression of three molecules (COX-2, TFF1, Src) implicated in the pathogenesis of gastric cancer using immunohistochemistry. RESULTS: We found that patients younger than 50 years of age had a better 5-year survival rate in all tumor stages. We found that the expression of COX-2 and Src correlated significantly with survival in this group without any significant impact attributable to TFF1. CONCLUSIONS: Our study demonstrates that young gastric cancer patients have a better prognostic outlook that could in part be explained by the differential expression of COX-2 and Src.

Is there a disadvantage to radical lymph node dissection in colon cancer?

BACKGROUND: The necessity for radical lymph node dissection for solid tumours was discussed in the past controversially. The aim of this study was to correlate the oncologic results of radical surgery for colon cancer with potential complications. METHODS: A total of 1,453 patients with R0-resected colon cancer operated on between 1978 and 2004 were analysed in a prospective database. The follow-up was at least 5 years. Rates of survival, locoregional and distant recurrences and complications were calculated. RESULTS: To compare the oncological outcome, the time frame was divided into five periods. In the last cohort (2000-2004), we observed in stage I-III tumours a 5-year cancer-related survival rate of 90.1 %, compared to 82.1 % in the first cohort (1978-1984) (p = 0.061). The local recurrence rate could be reduced from 6.5 to 3.2 % in the same cohorts (p = 0.059). It reached the level of significance in the multivariate analysis. The rates of distant metastases did not change. For patients with stage III, the 5-year cancer survival rates increased from 62.0 to 81.8 % (p = 0.005). Morbidity and mortality were comparable to other studies even to those with limited lymph node dissections. CONCLUSION: Radical lymph node dissection in colon cancer is not associated with obvious disadvantages to the patient. Specific considerable side effects were not observed when the preparation is performed in embryonic planes preserving the autonomous nerves. The complication rates were not increased compared to other studies, even to those with limited lymphatic dissection. In addition, radical lymph node dissection in colon cancer may improve survival.

[Quality indicators of diagnosis and therapy in MRI-based neoadjuvant radiochemotherapy for rectal cancer - interim analysis of a Prospective Multicentre Observational Study (OCUM)]. / Qualitätsindikaktoren der Diagnose und Therapie bei MRT-basierter neoadjuvanter Radiochemotherapie des Rektumkarzinoms - Interimsanalyse einer prospektiven, multizentrischen Beobachtungsstudie (OCUM).

BACKGROUND: The interim analysis of a prospective multicentre observational study of selective neoadjuvant chemoradiotherapy (OCUM) in patients with rectal cancer should evaluate the quality of diagnosis and therapy as a prerequisite for continuation of the study. PATIENTS AND METHODS: 230 patients with the clinical stage cT2 - 4, each cN, M0 with radical tumour resection were enrolled until now. The values of 13 quality indicators were compared with the target values formulated by the workflow of the Working Group rectal cancer II and the German Cancer Society and were also compared with the results of the certified bowel centres of Germany 2010. RESULTS: The target values were fulfilled to a high degree regardless of caseload. 83 % of parameters have been fully achieved and 14 % nearly achieved. In primary surgery the proportion of patients with 12 or more histologically examined lymph nodes was 99.2 %, after neoadjuvant chemoradiotherapy 90 %. A R0 resection was performed in 98.3 % and a resection of TME in muscularis propria plane only in 2.2 %. The rate of positive circumferential resection margins (pCRM + ) was 5.7 % only. CONCLUSIONS: The high quality of rectal surgery justifies the concept and the continuation of the study.

Pythium insidiosum: insights into biofilm formation and antibiofilm activity of antifungal drugs.

In this study, we investigate the ability of Pythium insidiosum to form biofilms across various substrates and the antibiofilm efficacy of 8-hydroxyquinoline derivatives (8-HQs). Biofilms of P. insidiosum were cultured on polystyrene plates, contact lenses, and horsehair. We provide the first evidence of P. insidiosum's biofilm-forming capability, thus considerably expanding our understanding of its transmission and pathogenesis. Our results demonstrate that 8-HQs effectively inhibit biofilm formation and eradicate pre-existing biofilms, underscoring their potential as a novel treatment strategy for pythiosis, a disease currently lacking a gold-standard treatment. This finding has particular relevance for ocular pythiosis associated with contact lens usage and potential infection sources in animals. Our results contribute to the scientific knowledge base and directly impact innovative therapeutic interventions' development.

Characterization of addressability by simultaneous randomized benchmarking.

The control and handling of errors arising from cross talk and unwanted interactions in multiqubit systems is an important issue in quantum information processing architectures. We introduce a benchmarking protocol that provides information about the amount of addressability present in the system and implement it on coupled superconducting qubits. The protocol consists of randomized benchmarking experiments run both individually and simultaneously on pairs of qubits. A relevant figure of merit for the addressability is then related to the differences in the measured average gate fidelities in the two experiments. We present results from two similar samples with differing cross talk and unwanted qubit-qubit interactions. The results agree with predictions based on simple models of the classical cross talk and Stark shifts.