Interlacing families and the Hermitian spectral norm of digraphs

Greaves, Gary,Mohar, Bojan,O, Suil Elsevier 2019 Linear algebra and its applications Vol.564 No.-

<P><B>Abstract</B></P> <P>It is proved that for any finite connected graph <I>G</I>, there exists an orientation of <I>G</I> such that the spectral radius of the corresponding Hermitian adjacency matrix is smaller or equal to the spectral radius of the universal cover of <I>G</I> (with equality if and only if <I>G</I> is a tree). This provides a suitable answer to a problem proposed by Mohar. The proof uses the method of interlacing families of polynomials that was developed by Marcus, Spielman, and Srivastava in their seminal work on the existence of infinite families of Ramanujan graphs.</P>

A Stabilizing Agent, PCA/DTPA, Improves Plasma Storage Life for the Chromsystems Vitamin C Assay up to Six Months

Collie Jake TB,Hudson Elizabeth P,Deane Adam M,Bellomo Rinaldo,Greaves Ronda F 대한진단검사의학회 2021 Annals of Laboratory Medicine Vol.41 No.4

The commonly used Chromsystems vitamin C (ascorbate) assay (Munich, Germany) has a sample storage life of five days at –20°C. Stabilizing agents have been successfully used to increase longevity; however, their suitability with this commercial assay is unclear. We investigated the compatibility of a stabilizing agent, perchloric acid/diethylenetriaminepentaacetic acid (PCA/DTPA), with the Chromsystems assay. Plasma was stored at –80°C, with or without PCA/DTPA. Storage up to six months was assessed through baseline and repeat analyses, stability was assessed by comparing paired non-stabilized and PCA/DTPA-stabilized plasma, and performance was assessed using allowable performance specifications of an external quality assurance program. Ascorbate concentration was significantly lower in non-stabilized plasma than in paired PCA/DTPA-stabilized plasma, with a proportional difference of 11% (P=0.01). All storage analysis results were within the allowable performance specifications. Storage at –80°C prevented plasma ascorbate oxidation; however, substantial oxidation occurred during sample processing. In conclusion, PCA/DTPA significantly reduces ascorbate oxidation, and PCA/DTPA-stabilized ascorbate plasma is compatible with the Chromsystems assay and stable for up to six months, when stored at –80°C.

Abnormal Myocardial Blood Flow Reserve Observed in Cardiac Amyloidosis

Michael Chi Yuan Nam,Karen Nel,Roxy Senior,Kim Greaves 한국심초음파학회 2016 Journal of Cardiovascular Imaging (J Cardiovasc Im Vol.24 No.1

We performed real-time myocardial contrast echocardiography on a patient with cardiac amyloidosis and previous normal coronary angiography presenting with atypical chest pain to assess myocardial blood flow reserve (MBFR). Myocardial contrast echocardiography was performed and flash microbubble destruction and replenishment analysis was used to calculate myocardial blood flow. Dipyridamole was used to achieve hyperemia. MBFR was derived from the ratio of peak myocardial blood flow at hyperemia and rest. The results show a marked reduction in MBFR in our patient. Previous reports of luminal obstruction of intramyocardial rather than epicardial vessels by amyloid deposition may be causing microvascular dysfunction.

HCV, Alcoholic : PE-135 ; Boceprevir plus peginterferon/ribavirin for the treatment of HCV/HIV co-infected patients: End of treatment (WEEK 48) interim results

( J Mallolas ),( S Pol ),( A Rivero ),( H Fainboim ),( C Cooper ),( J Slim ),( S Thompson ),( J Wahl ),( W Greaves ),( M Sulkowski ) 대한간학회 2012 춘·추계 학술대회 (KASL) Vol.2012 No.-

Background: Addition of boceprevir (BOC) to peginterferon (P) and ribavirin (R) significantly increases SVR among HCV- monoinfected patients for whom SVR rates have been low. The objective of this phase 2 trial was to investigate the efficacy and safety of BOC+P/R in HCV/HIV-coinfected patients. Methods: In this multicenter, double-blind, international trial, patients with untreated hepatitis C genotype 1 infections and HIV RNA <50 copies/mL were randomized 2:1 to receive P (PEG 2b 1.5 ug/kg/wk)/R (600-1400 mg/day, by weight) + BOC 800mg TID or P/R+placebo for 44 weeks, after a 4-week lead-in of P/R. NNRTIs, zidovudine, or didanosine were not permitted. Patients were stratified by: cirrhosis/fibrosis (yes vs. no) and baseline HCV-RNA (<800,000 IU/mL vs ≥800,000 IU/mL). The primary efficacy endpoint was SVR, undetectable plasma HCV-RNA 24 weeks after end of treatment (EOT). Secondary endpoints and planned interim analyses included proportion of subjects with undetectable HCV-RNA at treatment week (TW) 4, 8, 12, 24 and 48/EOT. Results: 100 patients were randomized between 11/2009 and 12/2010; 2 patients in the BOC arm did not receive medication; thus, 34 control and 64 experimental patients were treated. The majority were non-cirrhotic (95%), white (82%), male (69%) with median age ~43 years. Most had high baseline HCV-RNA (88%) and HCV genotype 1a (65%). At TW48/EOT, the rate of undetectable HCV-RNA was 63.9% and 29.4% in the BOC and control arms, respectively (Table). 61% of the BOC group and 32% of the control group completed 48 weeks of treatment; 20% and 9%, respectively, discontinued due to adverse events. HCV treatment failure occurred in 9% of the BOC group and 53% of the control group. BOC patients were more likely than controls to have decreased appetite, pyrexia, dysgeusia, vomiting, asthenia, anemia, and neutropenia. By TW48, 2 patients in the BOC group and 3 in the control group had HIV virologic failure. Conclusion: The addition of BOC to P/R was associated with higher rates of undetectable HCV-RNA at all time points, including TW48/EOT. The safety and tolerability profile was consistent with that observed in HCV-monoinfected patients.

Relationship Between Epicardial Fat Volume and Coronary Microvascular Dysfunction in Patients with Chest Pain and Unobstructed Coronary Arteries

Jing Xian Quah,Stephanie Sargent,Karen Nel,Christopher M. Anstey,Tony Stanton,Kim Greaves 아시아심장혈관영상의학회 2020 Cardiovascular Imaging Asia Vol.4 No.1

Objective: Epicardial fat (EF) is metabolically active adipose tissue positioned between the epicardial surface of the heart and the pericardium. We investigated whether there is a relationship between EF and Coronary Microvascular Dysfunction (CMD) in patients presenting with chest pain and unobstructed coronary arteries. Materials and Methods: This study recruited patients referred to cardiology clinics for assessment of chest pain who subsequently underwent assessment via CT coronary angiogram (CTA). Myocardial blood flow reserve (MBFR) was assessed using myocardial contrast echocardiography. Epicardial fat volume (EFV) was measured by tracing serial slices on CTA with corresponding Hounsfield units of -195 to -45. Results: We recruited 134 participants with a mean age of 59.2 (9.8) years. CMD was present in 54 (40%) patients, and the measured mean EFV was 128 mm3 (96, 168). Fortythree patients (32%) had a coronary artery calcium score (CACS) of 0, 64 (48%) had a CACS of 1–100, 18 (13%) had a CACS of 101–400, and 9 (7%) had a CACS >400. Univariate regression analysis showed that EFV and MBFR had a correlation coefficient of R=-0.22, with a significant regression slope (β=-0.002, p=0.012). Multivariable linear regression analysis using MBFR as a continuous outcome variable revealed age (β=-0.012, p=0.011) and CACS (β=-0.003, p= 0.023) to be associated with MBFR. EFV was not associated with MBFR (β=-0.0007, p=0.538). Model repetition with MBFR as a dichotomous variable (MBFR ≥2 or <2) revealed no association with EFV. Conclusion: No relationship was found between EFV and MBFR when traditional cardiovascular risk factors and calcium score.

The LEAP Checklist for Laboratory Evaluation and Analytical Performance Characteristics Reporting of Clinical Measurement Procedures

Loh Tze Ping,Cooke Brian R,Tran Thi Chi Mai,Markus Corey,Zakaria Rosita,Ho Chung Shun,Theodorsson Elvar,Greaves Ronda F 대한진단검사의학회 2024 Annals of Laboratory Medicine Vol.44 No.2

Reporting a measurement procedure and its analytical performance following method evaluation in a peer-reviewed journal is an important means for clinical laboratory practi- tioners to share their findings. It also represents an important source of evidence base to help others make informed decisions about their practice. At present, there are significant variations in the information reported in laboratory medicine journal publications describ- ing the analytical performance of measurement procedures. These variations also chal- lenge authors, readers, reviewers, and editors in deciding the quality of a submitted manu- script. The International Federation of Clinical Chemistry and Laboratory Medicine Working Group on Method Evaluation Protocols (IFCC WG-MEP) developed a checklist and recom- mends its adoption to enable a consistent approach to reporting method evaluation and analytical performance characteristics of measurement procedures in laboratory medicine journals. It is envisioned that the Laboratory Evaluation and Analytical Performance Char- acteristics (LEAP) checklist will improve the standardisation of journal publications describ- ing method evaluation and analytical performance characteristics, improving the quality of the evidence base that is relied upon by practitioners.

HCV : PE-135 ; Boceprevir plus peginterferon/ribavirin for the treatment of HCV/HIV co-infected patients: End of treatment (WEEK 48) interim results

( J Mallolas ),( S Pol ),( A Rivero ),( H Fainboim ),( C Cooper ),( J Slim ),( S Thompson ),( J Wahl ),( W Greaves ),( M Sulkowski ) 대한간학회 2012 춘·추계 학술대회 (KASL) Vol.2012 No.1

Background: Addition of boceprevir (BOC) to peginterferon (P) and ribavirin (R) significantly increases SVR among HCVmonoinfected patients for whom SVR rates have been low. The objective of this phase 2 trial was to investigate the efficacy and safety of BOC+P/R in HCV/HIV-coinfected patients. Methods: In this multicenter, double-blind, international trial, patients with untreated hepatitis C genotype 1 infections and HIV RNA <50 copies/mL were randomized 2:1 to receive P (PEG 2b 1.5 ug/kg/wk)/R (600-1400 mg/day, by weight) + BOC 800mg TID or P/R+placebo for 44 weeks, after a 4-week lead-in of P/R. NNRTIs, zidovudine, or didanosine were not permitted. Patients were stratified by: cirrhosis/fibrosis (yes vs. no) and baseline HCV-RNA (<800,000 IU/mL vs ≥800,000 IU/mL). The primary efficacy endpoint was SVR, undetectable plasma HCV-RNA 24 weeks after end of treatment (EOT). Secondary endpoints and planned interim analyses included proportion of subjects with undetectable HCV-RNA at treatment week (TW) 4, 8, 12, 24 and 48/EOT. Results: 100 patients were randomized between 11/2009 and 12/2010; 2 patients in the BOC arm did not receive medication; thus, 34 control and 64 experimental patients were treated. The majority were non-cirrhotic (95%), white (82%), male (69%) with median age ~43 years. Most had high baseline HCV-RNA (88%) and HCV genotype 1a (65%). At TW48/EOT, the rate of undetectable HCV-RNA was 63.9% and 29.4% in the BOC and control arms, respectively (Table). 61% of the BOC group and 32% of the control group completed 48 weeks of treatment; 20% and 9%, respectively, discontinued due to adverse events. HCV treatment failure occurred in 9% of the BOC group and 53% of the control group. BOC patients were more likely than controls to have decreased appetite, pyrexia, dysgeusia, vomiting, asthenia, anemia, and neutropenia. By TW48, 2 patients in the BOC group and 3 in the control group had HIV virologic failure. Conclusion: The addition of BOC to P/R was associated with higher rates of undetectable HCV-RNA at all time points, including TW48/EOT. The safety and tolerability profile was consistent with that observed in HCV-monoinfected patients. PE-136 Sustained virologic response (SVR) in prior peginterferon/ribavirin (PR) treatment failures after retreatment with boceprevir (BOC) + PR: The PROVIDE study interim results JP Bronowicki1, M Davis2, S Flamm3, S Gordon4, E Lawitz5, E Yoshida6, J Galati7, V Luketic8, J McCone9, I Jacobson10, P Marcellin11-12, A Muir13, F Poordad14, LD Pedicone15, W Deng15, M Treitel15, J Wahl15, J Vierling16 1University Henri Poincare of Nancy, Vandoeuvre-les-Nancy, France; 2South Florida Center of Gastroenterology, Wellington, FL, USA; 3Northwestern Feinberg School of Medicine, Chicago, IL, USA; 4Henry Ford Hospital, Detroit, MI, USA; 5Alamo Medical Research, San Antonio, TX, USA; 6University of British Columbia and Vancouver General Hospital, Vancouver, BC, Canada; 7Liver Specialists of Texas, Houston, TX, USA; 8Virginia Commonwealth University School of Medicine, Richmond, VA, USA; 9Mt. Vernon Endoscopy Center, Alexandria, VA, USA; 10Weill Cornell Medical College, New

Automated brainstem segmentation detects differential involvement in atypical parkinsonian syndromes

Martina Bocchetta,Juan Eugenio Iglesias,Viorica Chelban,Edwin Jabbari,Ruth Lamb,Lucy L. Russell,Caroline V. Greaves,Mollie Neason,David M. Cash,David L. Thomas,Jason D. Warren,John Woodside,Henry Houl 대한파킨슨병및이상운동질환학회 2020 Journal Of Movement Disorders Vol.13 No.1

Brainstem segmentation has been useful in identifying potential imaging biomarkers for diagnosis and progression in atypical parkinsonian syndromes (APS). However, the majority of work has been performed using manual segmentation, which is time consuming for large cohorts.

Elbasvir/Grazoprevir (EBR/GZR) Does Not Worsen Renal Function in Patients with Hepatitis C Virus (HCV) Infection and Pre-Existing Renal Disease

( K. Rajender Reddy ),( David Roth ),( Annette Bruchfeld ),( Peggy Hwang ),( Barbara Haber ),( Bach-yen T. Nguyen ),( Eliav Barr ),( Janice Wahl ),( Wayne Greaves ),( Youngmi Eun ) 대한간학회 2017 춘·추계 학술대회 (KASL) Vol.2017 No.1

Aims: Decreased estimated glomerular filtration rate (eGFR) has been reported in patients with HCV infection receiving direct-acting antiviral agents. EBR/GZR was safe and efficacious in patients with chronic kidney disease stage 4/5 (CKD 4/5) in the C-SURFER study. The aim of this analysis was to evaluate the impact of EBR/GZR on eGFR in patients with less severe CKD. Methods: We analyzed a pooled dataset of 1689 patients who received EBR/GZR (50 mg/100 mg) with or without ribavirin (RBV) for 8 (n=91, 5%), 12 (n=1238, 73%), 16 (n=211, 12%), or 18 (n=149, 9%) weeks (656 patients [39%] received RBV). Patients were treatment-naïve or treatment-experienced, and included cirrhotics and those with HIV co-infection. Creatinine values were assessed at baseline and ≥1 post-baseline timepoint. eGFR was calculated using the Modified Diet in Renal Disease equation at baseline, end of treatment, and 12 weeks post-therapy. Results: Of the 1689 patients evaluated, 32 had CKD 3 (eGFR < 60 mL/min/1.73 m2 to ≥30 mL/min/1.73 m2) and 1657 had eGFR >60 mL/min/1.73 m2 (Table). Demographics were similar in both groups except for a higher proportion of HIV-co-infected patients in the CKD 3 group (41% vs. 17%). Patients with CKD 3 and those with eGFR >60 mL/min/1.73 m2 at baseline did not show any decrease in eGFR during treatment or follow-up. Conclusions: EBR/GZR did not affect eGFR in patients with pre-existing eGFR >60 mL/min/1.73 m2 or those with CKD3. Treatment duration, RBV co-administration, cirrhosis, or HIV coinfection did not adversely affect renal outcome.

Rings and gaps in the disc around Elias 24 revealed by ALMA

Dipierro, G,Ricci, L,Pé,rez, L,Lodato, G,Alexander, R D,Laibe, G,Andrews, S,Carpenter, J M,Chandler, C J,Greaves, J A,Hall, C,Henning, T,Kwon, W,Linz, H,Mundy, L,Sargent, A,Tazzari, M,Testi, L,W Oxford University Press 2018 Monthly notices of the Royal Astronomical Society Vol.475 No.4