Listeriolysin O Drives Innate and Adaptive Immune Responses to CD47 Immunotherapy

PURPOSE/OBJECTIVE(S)

Radioimmunotherapies that combine radiation with antibodies against the "don't eat me" signal CD47 show increasing promise. One opportunity to synergize RT with anti-CD47 is via the Stimulator of Interferon Genes (STING) pathway which facilitates potent immune responses to cytoplasmic DNA. Anti-CD47 should activate STING by increasing macrophage consumption of tumor DNA. However, tumor contents are destroyed in phagolysosomes. Listeria (L.) monocytogenes escape lysosomes by secreting a pore-forming protein Listeriolysin O (LLO). We recently engineered a protein-antibody conjugate linking anti-CD47 to LLO. Here, we demonstrate that LLO-CD47 enhances macrophage STING signaling, tumor cell phagocytosis, and tumor antigen presentation. At doses compatible with minimal toxicity in mice, LLO-CD47 delays the growth of orthotopic breast tumors. By contrast, anti-CD47 fails to activate STING in macrophages or inhibit tumor growth. We further hypothesize that LLO-CD47 requires innate and adaptive immune cells for antitumor immunity.

MATERIALS/METHODS

Anti-CD47 was conjugated to LLO using a water-soluble SPDP crosslinker and purified by affinity chromatography. Transmission electron microscopy (TEM) was used to visualize the integrity of macrophage phagolysosomes following treatment. C57B6 mouse bone marrow-derived macrophages (BMDMs) were used to study the impact of LLO-CD47 on M2-to-M1 polarization, tumor cell phagocytosis, STING activation, and antigen presentation. CD8+ T cells or tumor-associated macrophages (TAMs) were depleted from tumor-bearing mice using an anti-CD8 antibody or anti-CSF-1R antibody prior to LLO-CD47 treatment.

RESULTS

(1) LLO-CD47 skews BMDMs from M2-to-M1 inflammatory phenotypes and enhances the phagocytosis of E0771 tumor cells. (2) BMDMs visualized by TEM show breaches in phagosome membranes following LLO-CD47, but not anti-CD47, treatment. (3) LLO-CD47 increases levels of phosphorylated STING, IFN, and TNFα relative to cells treated with anti-CD47. (4) LLO-CD47 significantly inhibits the growth of orthotopically implanted E0771 murine breast tumors relative to anti-CD47. (5) The elimination of CD8+ T cells or TAMs abrogates the antitumor effect of LLO-CD47.

CONCLUSION

LLO-CD47 is a de novo protein-antibody conjugate engineered for cGAS-STING pathway activation in innate immune cells. CD8+ T cells and TAMs are required for the antitumor activity LLO-CD47 in orthotopic models of breast cancer. This novel immunotherapy builds on clinical interest in myeloid checkpoint inhibitors and may be studied as a supplemental therapy for patients with metastatic breast cancer.

A Rare Case of Extralaryngeal Schwannoma Arising from the Superior Laryngeal Nerve

Schwannomas are the most common neurogenic tumours arising in the parapharyngeal space. Usually they arise from the vagus nerve but rarely have an extralaryngeal presentation arising from the superior laryngeal nerve. In the case reported here, cytology could not confirm the diagnosis and imaging could not identify the nerve of origin.

Reducing Perinatal Mortality in India: Two-Years Results of the IRIA Fetal Radiology Samrakshan Program

Aim The aim of the study is to determine improvements in perinatal mortality at the end of the first 2 years from the initiation of the Samrakshan program of the Indian Radiological and Imaging Association.

Methods Samrakshan is a screening program of pregnant women that uses trimester-specific risk assessment protocols including maternal demographics, mean arterial pressure, and fetal Doppler studies to classify women as high risk or low risk for preterm preeclampsia (PE) and fetal growth restriction (FGR). Low dose aspirin 150 mg daily once at bedtime was started for pregnant women identified as high risk in the 11–136/7 weeks screening. The third-trimester screening focused on the staging of FGR and protocol-based management for childbirth and risk assessment for PE. Outcomes of childbirth including gestational age at delivery, development of PE, and perinatal mortality outcomes were collected.

Results Radiologists from 38 districts of 16 states of India participated in the Samrakshan program that screened 2,816 first trimester, 3,267 second trimester, and 3,272 third trimester pregnant women, respectively. At 2 years, preterm PE was identified in 2.76%, preterm births in 19.28%, abnormal Doppler study in 25.76% of third trimester pregnancies, and 75.32% of stage 1 FGR delivered at term. The neonatal mortality rate was 9.86/1,000 live births, perinatal mortality rate was 18.97/1,000 childbirths, and maternal mortality was 58/100,000 live births compared with 29.5, 36, and 113, respectively in 2016.

Conclusion Fetal Doppler integrated antenatal ultrasound studies in Samrakshan led to a significant reduction in preterm PE rates, preterm birth rates, and a significant improvement in mean birth weights. Perinatal, neonatal, and maternal mortality rates are significantly better than the targets for 2030 set by the Sustainable Development Goals-3.

POS1189 THE IMPACT OF TELEMEDICINE AND COVID-19 ON A TERTIARY RHEUMATOLOGY SERVICE: A RETROSPECTIVE AUDIT

Background:

Telemedicine was widely utilised to complement face-to-face (F2F) care in 2020 during the COVID-19 pandemic, but the impact of this on patient care is poorly understood.

Objectives:

To investigate the impact of telemedicine during COVID-19 on outpatient rheumatology services.

Methods:

We retrospectively audited patient electronic medical records from rheumatology outpatient clinics in an urban tertiary rheumatology centre between April-May 2020 (telemedicine cohort) and April-May 2019 (comparator cohort). Differences in age, sex, primary diagnosis, medications, and proportion of new/review appointments were assessed using Mann-Whitney U and Chi-square tests. Univariate analysis was used to estimate associations between telemedicine usage and the ability to assign a diagnosis in patients without a prior rheumatological diagnosis, the frequency of changes to immunosuppression, subsequent F2F review, planned admissions or procedures, follow-up phone calls, and time to next appointment.

Results:

3,040 outpatient appointments were audited: 1,443 from 2019 and 1,597 from 2020. There was no statistically significant difference in the age, sex, proportion of new/review appointments, or frequency of immunosuppression use between the cohorts. Inflammatory arthritis (IA) was a more common diagnosis in the 2020 cohort (35.1% vs 31%, p=0.024). 96.7% (n=1,444) of patients seen in the 2020 cohort were reviewed via telemedicine. In patients without an existing rheumatological diagnosis, the odds of making a diagnosis at the appointment were significantly lower in 2020 (28.6% vs 57.4%; OR 0.30 [95% CI 0.16-0.53]; p<0.001). Clinicians were also less likely to change immunosuppressive therapy in 2020 (22.6% vs 27.4%; OR 0.78 [95% CI 0.65-0.92]; p=0.004). This was mostly driven by less de-escalation in therapy (10% vs 12.6%; OR 0.75 [95% CI 0.59-0.95]; p=0.019) as there was no statistically significant difference in the escalation or switching of immunosuppressive therapies. There was no significant difference in frequency of follow-up phone calls, however, patients seen in 2020 required earlier follow-up appointments (p<0.001). There was also no difference in unplanned rheumatological presentations but significantly fewer planned admissions and procedures in 2020 (1% vs 2.6%, p=0.002). Appointment non-attendance reduced in 2020 to 6.5% from 10.9% in 2019 (OR 0.57 [95% CI 0.44-0.74]; p<0.001), however the odds of discharging a patient from care were significantly lower in 2020 (3.9% vs 6%; OR 0.64 [95% CI 0.46-0.89]; p=0.008), although there was no significance when patients who failed to attend were excluded. Amongst patients seen via telemedicine in 2020, a subsequent F2F appointment was required in 9.4%. The predictors of needing a F2F review were being a new patient (OR 6.28 [95% CI 4.10-9.64]; p<0.001), not having a prior rheumatological diagnosis (OR 18.43 [95% CI: 2.35-144.63]; p=0.006), or having a diagnosis of IA (OR 2.85 [95% CI: 1.40-5.80]; p=0.004) or connective tissue disease (OR 3.22 [95% CI: 1.11-9.32]; p=0.031).

Conclusion:

Most patients in the 2020 cohort were seen via telemedicine. Telemedicine use during the COVID-19 pandemic was associated with reduced clinic non-attendance, but with diagnostic delay, reduced likelihood of changing existing immunosuppressive therapy, earlier requirement for review, and lower likelihood of discharge. While the effects of telemedicine cannot be differentiated from changes in practice related to other aspects of the pandemic, they suggest that telemedicine may have a negative impact on the timeliness of management of rheumatology patients.

Disclosure of Interests:

None declared.

AB0736 SEVERITY OF NAIL PSORIASIS SCORE (SNAPS) IS SENSITIVE TO CHANGE IN A COHORT OF PATIENTS WITH PSORIATIC ARTHRITIS TREATED WITH ETANERCEPT

Background:

The Severity of Nail Psoriasis Score (SNAPS; range 0-40: scored one point each for the presence of pitting, onycholysis, hyperkeratosis and/or severe nail disease#in each fingernail) has been utilised to collect data regarding psoriatic nail dystrophy in the Bath Psoriatic Arthritis (PsA) Longitudinal cohort for many years. SNAPS has construct validity in PsA with the modified Nail Psoriasis Severity Index (mNAPSI) as a comparator instrument and appears to be more feasible than mNAPSI with excellent reliability1.

Objectives:

We aimed to determine if SNAPS could demonstrate longitudinal sensitivity to change in a cohort of patients treated with biological disease modifying anti-rheumatic drugs (bDMARDs) and therefore be utilized prospectively in observational and clinical trial settings.

Methods:

Patients enrolled in the Bath PsA longitudinal cohort routinely undergo clinical assessments including a 66/68 Swollen and Tender Joint Count (SJC/TJC), Psoriasis Area Severity Index (PASI), Patient Global Assessment (PtGA) and Physician Global Assessment (PhGA), as well as complete patient-reported outcome measures such as the Health Assessment Questionnaire (HAQ) and Dermatology Quality of Life (Derm-QoL). All patients who commenced treatment with Etanercept and had available outcome data at baseline, 3 months and 6 months were included in this retrospective analysis. Baseline demographics were recorded and paired t-tests were utilized to assess the change in SNAPS at 3 and 6 months. The effect size and measurement error of SNAPS in this cohort were measured. Correlations between SNAPS and other outcome measures were assessed using Pearson’s r.

Results:

Fifty-seven patients (32 male and 25 female) with available data were retrospectively analysed. The mean (±SD) age of the cohort and duration of disease was 61.3 (±11.55) and 13.3 (±10.82) years respectively. The mean SNAPS at baseline was 3.7 (±6.13) and improved to 2.0 (3.74, p=0.018) at 3 months and 1.2 (2.40) at 6 months (p=0.001 for change from baseline and p=0.039 for change from month 3). The smallest detectable difference at 3 months for SNAPS in this cohort was 1.35, representing 3.37% of the range of the score (Table 2). The standardised response mean (SRM) was 0.32 at 3 months and 0.44 at 6 months. There was a modest correlation between the improvement in the SNAPS score and the improvement in PASI and Derm QOL at 3 months (r = 0.511 and 0.558 respectively, p=0.001) and 6 months (r= 0.672, p<0.001 and r=0.510, p=0.003 respectively).

Conclusion:

SNAPS demonstrates sensitivity to change in response to treatment with a bDMARD and could be a potential outcome measure for the assessment of treatment efficacy in prospective studies.

References:

[1]Antony A, Hart D, Cavill C, Korendowych E, McHugh N, Lovell C, Tillett W. The ‘Severity of Nail Psoriasis Score’ (SNAPS) Is Feasible, Reliable and Demonstrates Construct Validity Against the mNAPSI in an Observational Cohort of Patients with Psoriatic Arthritis [abstract].Arthritis Rheumatol.2019; 71 (suppl 10).

Table 1.

Outcomes at Baseline, 3 months and 6 months

Mean (SD) or Median [IQR]Baseline3 Months(p for change from baseline)6 Months(p for change from baseline)PASI (0-72)3.0 (4.80)1.6 (2.12) p=0.011.3 (1.6) p=0.002SNAPS (0-40)3.7 (6.13)2.0 (3.73) p=0.0181.2 (2.39) p=0.001Derm-QoL (0-30)5.7 (7.07)1.95 (3.23) p=0.001 (n=33)1.9(4.72) p=0.037 (n=31)Table 2.

Measurement Error for SNAPS in an Etanercept Cohort

TimeframeStandardised Response MeanStandard Error of MeanSmallest Detectable ChangeSmallest Detectable Change (% of total score)Smallest Detectable DifferenceSmallest Detectable Difference (% of total score)0-3 months0.320.691.914.771.353.370-6 months0.440.742.065.151.463.64

Disclosure of Interests:

Anna Antony: None declared, Sadaf Saeed: None declared, Darren Hart: None declared, Preeti Nair: None declared, Charlotte Cavill: None declared, Eleanor Korendowych: None declared, Neil McHugh: None declared, Christopher Lovell: None declared, William Tillett Grant/research support from: AbbVie, Celgene, Eli Lilly, Janssen, Novartis, Pfizer Inc, UCB, Consultant of: AbbVie, Amgen, Celgene, Lilly, Janssen, Novartis, MSD, Pfizer Inc, UCB, Speakers bureau: AbbVie, Amgen, Celgene, Lilly, Janssen, Novartis, Pfizer Inc, UCB

AB0839 RELIABILITY OF COMPOSITE MEASURES FOR THE ASSESSMENT OF PSORIATIC ARTHRITIS

Background:

Composite measures of disease activity have been developed for use in Psoriatic Arthritis (PsA) to capture the wide spectrum of disease but there is a lack of consensus regarding which to adopt for routine practice. It is recognised that more data is required to understand the measurement properties of existing instruments and consider the impact of modifications that may improve face validity, responsiveness or feasibility. It is important to have an estimate of a measurement instrument’s reliability in the setting of stable disease in order to understand measurement error and responsiveness. To our knowledge no data exists on the stability of composite measures in PsA.

Objectives:

To measure test re-test reliability of composite measures of disease activity in PsA.

Methods:

Clinical and patient reported outcomes to enable the calculation of composite measures were administered to 141 patients with PsA at five time points in a UK multicentre observational study. All patients fulfilled the CASPAR criteria. Twenty-nine patients with clinically stable disease and receiving no treatment intervention underwent repeat assessment by the same examiner within 2 weeks. Patients in high and low disease were included. Reliability was evaluated by intra-class correlation coefficient (ICC) and Bland Altman plots.

Results:

Of the 29 patients included 15 were male, the mean age was 52.4 years (SD 13.39), mean disease duration at T0was 9.2yrs (SD 8.11). The mean swollen joint count was 3.4 (SD 5.1), tender joint count 11.3 (SD 15.03) and PASI 1.0 (SD1.04). The ICC (95% CI) for tender and swollen joint counts were 0.94 (0.87-0.97) and 0.91 (0.80-0.96) respectively. The ICC for PASI was 0.95 (0.90-0.98). All composite measures demonstrated high levels of test-retest reliability with ICC >0.85, table. The most reliable measure was the PADAS ICC 0.98 (95% CI 0.954-0.991). The individual ICC for each composite measures are reported in the table and Bland Altman plots, figure.

Conclusion:

All composite measures show high levels of test-retest reliability in this cohort. The PASDAS was the most stable measure. Modifications to these instruments can now be tested and the impact compared to the original versions.

Table.

Funding:

This report is independent research funded by the National Institute for Health Research, Programme Grants for Applied Research [Early detection to improve outcome in patients with undiagnosed PsA (‘PROMPT’), RP-PG-1212-20007]. The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care.

Disclosure of Interests:

William Tillett Grant/research support from: AbbVie, Celgene, Eli Lilly, Janssen, Novartis, Pfizer Inc, UCB, Consultant of: AbbVie, Amgen, Celgene, Lilly, Janssen, Novartis, MSD, Pfizer Inc, UCB, Speakers bureau: AbbVie, Amgen, Celgene, Lilly, Janssen, Novartis, Pfizer Inc, UCB, Philip Helliwell: None declared, Oliver FitzGerald: None declared, Robin Waxman: None declared, Anna Antony: None declared, Laura C Coates: None declared, Deepak Jadon: None declared, Paul Creamer: None declared, Suzanne Lane: None declared, Marco Massarotti: None declared, Charlotte Cavill: None declared, Mel Brooke: None declared, Jonathan Packham: None declared, Eleanor Korendowych: None declared, Anya Lissina: None declared, Neil McHugh: None declared

AB0737 MEASUREMENT PROPERTIES OF RADIOGRAPHIC OUTCOME MEASURES IN PSORIATIC ARTHRITIS: A SYSTEMATIC REVIEW FROM THE GRAPPA-OMERACT INITIATIVE

Background:

Structural damage was identified as an important outcome domain in the Psoriatic Arthritis (PsA) Core Domain Set and should be assessed at least once in the development of a new therapeutic.

Objectives:

To conduct a systematic literature review (SLR) to identify studies addressing the measurement properties (MPs) for ROIs and appraise the evidence through the OMERACT Filter 2.1 Framework Instrument Selection Algorithm (OFISA). [1]

Methods:

An SLR was conducted in EMBASE and MEDLINE to identify full-text English studies developing or assessing MPs of ROIs in PsA. Determination of eligibility, data extraction and methodology asssessment were performed by 2 reviewers. MPs were rated according to the ‘Provisional Standards’ and assigned a Red/Amber/White/Green (RAWG) rating (Figure 1). [1, 2]

Results:

3621 references were screened, 531 full-text articles reviewed, and 12 were included (Figure 2). Nine instruments assessing peripheral radiographs and six assessing axial radiographs were identified (Table 1). Three of the nine peripheral radiographic instruments had adequate evidence for reliability and some evidence for construct validity: the modified Steinbrocker, Ratingen, and modified Sharp van der Heijde scores. There was scant evidence for reliability, construct validity and responsiveness for the axial ROIs, compounded by the lack of a standardized definition of axial PsA.

Conclusion:

This SLR summarizes the MPs of ROIs and identifies relevant knowledge gaps that need to be addressed prior to endorsement of an instrument for the PsA Core Domain Set.

References:

[1]Richards P and De Wit M, editors. The OMERACT Handbook (March 2019)

[2]Mokkink LB and D’Agostino MA. Protocol for performing a systematic review on imaging techniques (unpublished)

Figure 1.

Criteria for the RAWG Rating

Figure 2.

PRISMA Diagram

Table 1.

Summary of Measurement Properties

ROIDomain MatchFeasibilityConstruct ValidityDiscriminationReliabilityResponsivenessInter-raterIntra-raterMeasurement ErrorLongitudinal Construct ValidityClinical Trial DiscriminationThresholds of MeaningOriginal Steinbrocker ScoreA[1]A[1]R[1]Modified Steinbrocker Score#G[2]G[2]A[1]A[2]Modified Larsen ScoreA[1]A[1]A[1]*Ratingen Score#A[1]G[3]G[3]A[3]A[1]mTSS-AA[1]A[1]A[1]mTSS-B#A[1]A[1]A[1]A[1]*mSvdHs#A[2]G[2]G[2]A[1]A[1]*ReXPsAR[0]SPARS#A[1]A[1]A[1]Axial PsA Definition 1MSASSS#A[2]R[0]BASRI - Total#A[2]R[0]PASRI#A[2]R[0]Axial PsA Definition 2MSASSS#A[1]R[1]A[1]A[1]BASRI - Spine#R[1]A[1]A[1]PASRI#A[1]A[1]A[1]Modified NYC#R[1]A[1]RASSS#R[1]A[1]A[1]

A = Amber, R = Red, G = Green

[Total available studies for synthesis following excluding studies with poor methodology]

* RCT data available but no published effect sizes

# Feasibility data available

Disclosure of Interests:

Anna Antony: None declared, Richard Holland: None declared, Wieneke Mokkink: None declared, Maria-Antonietta d’Agostino: None declared, Walter P Maksymowych Grant/research support from: Received research and/or educational grants from Abbvie, Novartis, Pfizer, UCB, Consultant of: WPM is Chief Medical Officer of CARE Arthritis Limited, has received consultant/participated in advisory boards for Abbvie, Boehringer, Celgene, Eli-Lilly, Galapagos, Gilead, Janssen, Novartis, Pfizer, UCB, Speakers bureau: Received speaker fees from Abbvie, Janssen, Novartis, Pfizer, UCB., Heidi Bertheussen: None declared, Lori Schick: None declared, Niti Goel Shareholder of: UCB and Galapagos, Consultant of: VielaBio, Mallinckrodt, and IMMVention, Alexis Ogdie Grant/research support from: Pfizer, Novartis, Consultant of: Abbvie, Amgen, BMS, Celgene, Corrona, Janssen, Lilly, Pfizer, Novartis, Ana-Maria Orbai Grant/research support from: Abbvie, Eli Lilly and Company, Celgene, Novartis, Janssen, Horizon, Consultant of: Eli Lilly; Janssen; Novartis; Pfizer; UCB. Ana-Maria Orbai was a private consultant or advisor for Sun Pharmaceutical Industries, Inc, not in her capacity as a Johns Hopkins faculty member and was not compensated for this service., Pil Hoejgaard: None declared, Laura C Coates: None declared, Vibeke Strand Consultant of: AbbVie, Amgen, Biogen, Celltrion, Consortium of Rheumatology Researchers of North America, Crescendo Bioscience, Eli Lilly, Genentech/Roche, GlaxoSmithKline, Hospira, Janssen, Merck, Novartis, Pfizer, Regeneron Pharmaceuticals, Inc., Sanofi, UCB, Dafna D Gladman Grant/research support from: AbbVie, Amgen Inc., BMS, Celgene Corporation, Janssen, Novartis, Pfizer, UCB – grant/research support, Consultant of: AbbVie, Amgen Inc., BMS, Celgene Corporation, Janssen, Novartis, Pfizer, UCB – consultant, Robin Christensen: None declared, Ying Ying Leung Speakers bureau: Novartis, Janssen, Eli Lilly, Philip J Mease Grant/research support from: Abbott, Amgen, Biogen Idec, BMS, Celgene Corporation, Eli Lilly, Novartis, Pfizer, Sun Pharmaceutical, UCB – grant/research support, Consultant of: Abbott, Amgen, Biogen Idec, BMS, Celgene Corporation, Eli Lilly, Novartis, Pfizer, Sun Pharmaceutical, UCB – consultant, Speakers bureau: Abbott, Amgen, Biogen Idec, BMS, Eli Lilly, Genentech, Janssen, Pfizer, UCB – speakers bureau, William Tillett Grant/research support from: AbbVie, Celgene, Eli Lilly, Janssen, Novartis, Pfizer Inc, UCB, Consultant of: AbbVie, Amgen, Celgene, Lilly, Janssen, Novartis, MSD, Pfizer Inc, UCB, Speakers bureau: AbbVie, Amgen, Celgene, Lilly, Janssen, Novartis, Pfizer Inc, UCB

AB0735 SEVERITY OF NAIL PSORIASIS SCORE (SNAPS) DEMONSTRATES LONGITUDINAL CONSTRUCT VALIDITY AGAINST THE MODIFIED NAIL PSORIASIS SEVERITY INDEX (mNAPSI) IN AN OBSERVATIONAL COHORT OF PATIENTS WITH PSORIATIC ARTHRITIS

Background:

Longitudinal observational data on psoriatic nail dystrophy is scarce, in part due to the lack of a validated outcome measure that is feasible in routine care. The Severity of Nail Psoriasis Score (SNAPS; range 0-40: scored one point each for the presence of pitting, onycholysis, hyperkeratosis and/or severe nail disease#in each fingernail) has face validity and has recently demonstrated feasibility, reliability and cross-sectional construct validity against the modified Nail Psoriasis Severity Index (mNAPSI; range 0-130)1.

Objectives:

We aimed to assess the longitudinal construct validity of SNAPS against the mNAPSI and physician nail VAS (PhNVAS), and to determine the effect size and measurement error of these tools.

Methods:

Consenting consecutive patients enrolled in the Bath Psoriatic Arthritis (PsA) longitudinal cohort underwent photography of their fingernails at baseline1and 6 months alongside routine clinical assessments. Dorsal images of individual fingernails were acquired using a tripod mounted DSLR camera. An angled mirror positioned distally aided identification of hyperkeratosis. Photograps were scored using SNAPS, mNAPSI and PhNVAS1. Paired statistical analyses were conducted to assess for change in scores from baseline to follow-up. Pairwise correlations between change in SNAPS and change in mNAPSI and PhyNVAS were assessed using Spearman’s rho. Effect sizes and measurement error were calculated.

Results:

Fifteen patients with a mean (±SD) age of 54.5 (±10.59) were assessed at 6 months. There was a significant reduction in both the mNAPSI and SNAPS scores (p<0.005), with improvements in the most frequently-observed manifestations1i.e. pitting, onycholysis, hyperkeratosis and crumbling (Table 1). No other feature specific to mNAPSI improved over time. There was no significant change using the PhyNVAS. There was a strong correlation between changes in SNAPS and the mNAPSI (Figure 1; rho = 0.838, p<0.001). The correlation between change in SNAPS and PhyNVAS was not statistically significant (rho =0.45, p=0.095) (Figure 1). The change in mNAPSI correlated moderately with the PhNVAS (rho = 0.540, p=0.038). mNAPSI was superior to SNAPS in most parameters of measurement error (Table 2). The mNAPSI and SNAPS had similar effect sizes as measured by the SRM (Table 2).

Conclusion:

SNAPS demonstrates longitudinal construct validity against the mNAPSI in a small observational cohort of PsA patients as evidenced by a strong correlation between the measures, comparable effect sizes and sensitivity to change over time. Whilst measurement error parameters favored the mNAPSI, SNAPS may be a more feasible measure for studying nail disease in cohort studies.

References:

[1]Antony A, Hart D, Cavill C, Korendowych E, McHugh N, Lovell C, Tillett W. The ‘Severity of Nail Psoriasis Score’ (SNAPS) Is Feasible, Reliable and Demonstrates Construct Validity Against the mNAPSI in an Observational Cohort of Patients with Psoriatic Arthritis [abstract].Arthritis Rheumatol.2019; 71 (suppl 10).

Table 1.

Outcomes at Baseline and at Follow-Up:

OutcomeMean (SD) or Median (IQR) N=15t-test or Wilcoxon Sign Rank test (p-value)BaselineFollow-upSNAPS13.0 [8.00-21.00]5.0 [2.00-11.00]0.002*mNAPSI22.0 [12.00-35.00]6.0 [4.00-15.00]0.001*Physician Nail VAS23.3 (22.90)15.8 (15.22)0.147Physician Global VAS18.0 [10.75-32.75]15.0 [10.00-30.00]0.455Table 2.

Measurement error of SNAPS, mNAPSI, PtNVAS and PhyNVAS

SRMSEMSDCSDC % (% of total score)SDDSDD% (% of total score)SNAPS1.151.716.7216.793.368.40mNAPSI1.153.5113.7410.576.875.29Physician Nail VAS0.404.7118.4714.219.237.10Figure 1.

Correlation between changes in SNAPS and changes in mNAPSI

Disclosure of Interests:

Anna Antony: None declared, Sadaf Saeed: None declared, Darren Hart: None declared, Preeti Nair: None declared, Charlotte Cavill: None declared, Eleanor Korendowych: None declared, Neil McHugh: None declared, Christopher Lovell: None declared, William Tillett Grant/research support from: AbbVie, Celgene, Eli Lilly, Janssen, Novartis, Pfizer Inc, UCB, Consultant of: AbbVie, Amgen, Celgene, Lilly, Janssen, Novartis, MSD, Pfizer Inc, UCB, Speakers bureau: AbbVie, Amgen, Celgene, Lilly, Janssen, Novartis, Pfizer Inc, UCB

Engineering the Structural and Electronic Phases of MoTe2 through W Substitution

MoTe₂ is an exfoliable transition metal dichalcogenide (TMD) that crystallizes in three symmetries: the semiconducting trigonal-prismatic 2H- or α-phase, the semimetallic and monoclinic 1T^'- or β-phase, and the semimetallic orthorhombic γ-structure. The 2H-phase displays a band gap of ∼1 eV making it appealing for flexible and transparent optoelectronics. The γ-phase is predicted to possess unique topological properties that might lead to topologically protected nondissipative transport channels. Recently, it was argued that it is possible to locally induce phase-transformations in TMDs, through chemical doping, local heating, or electric-field to achieve ohmic contacts or to induce useful functionalities such as electronic phase-change memory elements. The combination of semiconducting and topological elements based upon the same compound might produce a new generation of high performance, low dissipation optoelectronic elements. Here, we show that it is possible to engineer the phases of MoTe₂ through W substitution by unveiling the phase-diagram of the Mo_1-xW_xTe₂ solid solution, which displays a semiconducting to semimetallic transition as a function of x. We find that a small critical W concentration x_c ∼ 8% stabilizes the γ-phase at room temperature. This suggests that crystals with x close to x_c might be particularly susceptible to phase transformations induced by an external perturbation, for example, an electric field. Photoemission spectroscopy, indicates that the γ-phase possesses a Fermi surface akin to that of WTe₂.

Validation of the Lupus Impact Tracker in an Australian patient cohort

OBJECTIVES

The objective of this article is to validate the Lupus Impact Tracker (LIT), a disease-specific patient-reported outcome (PRO) tool, in systemic lupus erythematosus (SLE) patients in a multi-ethnic Australian cohort.

METHODS

Patients attending the Monash Lupus Clinic were asked to complete the LIT, a 10-item PRO. Psychometric testing assessing criterion validity, construct validity, test-retest reliability (TRT) and internal consistency reliability (ICR) were performed. We compared the LIT scores across patient characteristics, and correlations between LIT scores and SLEDAI-2k, PGA, and SLICC-SDI were examined.

RESULTS

LIT data were obtained from 73 patients. Patients were 84% female with a median age of 41 years, and 34% were Asian. The cohort had mild-moderate disease activity with a median (IQR) Systemic Lupus Erythematosus Disease Activity Index-2000 (SLEDAI-2k) of 4 (IQR 2-6). The median LIT score was 32.5 (IQR 17.5-50). LIT demonstrated criterion validity against SLEDAI-2k and SDI. Construct validity assessed by confirmatory factor analysis demonstrated an excellent fit (Goodness of fit index 0.95, Comparative Fit Index 1, Root Mean Square Error of Approximation <0.0001). The LIT demonstrated TRT with an overall intraclass correlation coefficient of 0.986 (95% CI 0.968-0.995). ICR was demonstrated with a Cronbach's alpha of 0.838. Patients with disability, low socioeconomic status, or higher disease activity had significantly worse LIT scores.

CONCLUSION

The LIT demonstrated properties consistent with its being valid in this population. Lower socioeconomic status appears to have a significant impact on patient-reported health-related quality of life in SLE.

Improved sensitivity of trypan blue dye exclusion assay with Ni2+ or Co2+ salts

A modified trypan blue dye exclusion assay was developed usingNi(2+) or Co(2+) salts to determine the viability ofprimary and transformed cells. When the cells were preincubatedwith NiSO(4) or CoCl(2) followed by trypan blue assay, thecontrast between stained and unstained cells was significantlyincreased as compared to the conventional trypan blue dyeexclusion assay.

Acute kidney injury after cardiac surgery in eastern Saudi Arabia

Acute kidney injury is a serious complication after cardiac surgery. This study was conducted to determine the frequency of acute kidney injury and the associated risk factors following cardiac surgery at Dhahran health centre in eastern Saudi Arabia. All patients who underwent cardiac surgery between June 2005 and December 2008 were included. Of 293 patients who fulfilled the criteria and were included in the final analysis, 85 (29.0%) developed acute kidney injury. Using multivariate analysis, the factors significantly associated with acute kidney injury were age, diabetes, preoperative chronic kidney disease and emergent surgery. Mortality associated with acute kidney injury was 10.5% overall and 42.9% when dialysis was required. Acute kidney injury following cardiac surgery is a serious problem among patients in eastern Saudi Arabia. Measures to prevent this complication are essential.

A serosurvey for antibodies toLeptospirain dogs in the lower North Island of New Zealand

AIMS

To investigate the prevalence of antibodies to endemic and exotic Leptospira serovars in samples from a serum bank, collected from dogs in the lower North Island of New Zealand.

METHODS

Sera (n=466), which had been collected from apparently healthy dogs, were screened using the microscopic agglutination test (MAT) for antibodies to serovars L. borgpeterseni serovar hardjo, L. interrogans serovars pomona, copenhageni and canicola, and L. kirschneri serovar grippotyphosa.

RESULTS

Antibody to Leptospiral antigen was found in 14.2% of dogs tested. The highest level of reactivity was with serovar copenhageni, to which 9.5% (41/433) of sera were positive. Antibodies to serovars grippotyphosa and canicola were not detected in this population of dogs.

CONCLUSIONS

Leptospira infection is relatively common in dogs in the lower North Island .

CLINICAL RELEVANCE

Vaccination of dogs against leptospirosis should be considered using vaccine containing antigen to serovars hardjo, pomona and copenhageni. The presence of moderate levels of copenhageni antibody in dogs in the lower North Island raises the possibility that this serovar has become established in rodent populations in this region.

Prevalence of antibodies to Neospora caninum in dogs of rural or urban origin in central New Zealand

AIM

To investigate the seroprevalence of Neospora caninum infection in populations of dogs from dairy farms, sheep/beef farms and urban areas in the central part of New Zealand. It was postulated seroprevalence would be higher for farm dogs than urban dogs if the life-cycle of this parasite involves transmission between dogs and cattle.

METHODS

Serum samples were obtained from dogs that lived on dairy farms (n=161), sheep/beef farms (n=154) and in urban situations (n=150). The relative risk of detecting antibodies to N. caninum using an immunofluorescent antibody test (IFAT) was compared between farm and urban dogs.

RESULTS

The relative risk of having a titre of > or = 1:200 to N. caninum was 2.43 (95% CI=1.88-3.14) for dairy-farm dogs and 3.16 (95% CI=2.48-4.02) for sheep/beef-farm dogs, compared with urban dogs. At this titre, which is currently used in New Zealand to indicate seropositivity, seroprevalence of N. caninum infection was 30.7% in urban dogs, 74.5% in dairy-farm dogs and 96.8% in sheep/beef-farm dogs.

CONCLUSION

This observation is consistent with a cycling of this disease between cattle and dogs on farms in New Zealand and with higher exposure of dogs to N. caninum on farms than occurs in urban environments. The prevalence of antibodies in all three groups of dogs tested in this study (dairy-farm dogs, sheep/beef-farm dogs and urban dogs) is higher than has generally been reported elsewhere. New Zealand farm dogs have a higher serological prevalence of N. caninum infection than urban dogs.

CLINICAL RELEVANCE

Management and disease control practices that break the life-cycle of transmission between cattle and dogs should assist in controlling cattle abortion due to N. caninum.

Recent advances in understanding the epidemiology of Neospora caninum in cattle

INTRODUCTION

Neospora caninum is the most frequently diagnosed cause of cattle abortion in New Zealand and is an important pathogen worldwide. The parasite has been found in aborted bovine foetuses and in puppies with neurological disease. Recent developments have provided new insights into the epidemiology of the disease that are reviewed in this article.

TRANSMISSION

Transplacental infection is of major importance in the spread of N. caninum overseas. Most congenital infections result in the birth of apparently healthy calves. Seroepidemiological studies indicate introduced point-source infections are also likely, as do investigations of abortion outbreaks in cattle herds attributed to N. caninum. Horizontal transmission is an important determinant of the stability of infection prevalence in a herd. Two potential sources of horizontal transmission that have recently been reported are: via a canine definitive host and; cow-to-calf transmission through pooled colostrum or milk. Transmission parameters for the organism have been estimated using mathematical modeling, to explore the epidemiology and options for control of N. caninum infection in dairy cattle in the absence of precise epidemiological data. LIFE-CYCLE: Seroepidemiologic studies, combined with the knowledge that dogs can be a definitive host, provide evidence supporting a dog-cattle life-cycle. The importance of dogs in the epidemiology of bovine neosporosis is not yet clear. It is likely that N. caninum oocysts in dog faeces could serve as a source of infection for cattle and recent studies have shown that the canine and bovine isolatesflare the same organism. Infection of cattle orally exposed to oocysts has been demonstrated experimentally but not in nature. It is not known if other wild carnivores may serve as definitive hosts of N. caninum.

CONCLUSION

Despite active research for over a decade, very little is known about the mechanisms of transmission of N. caninum. Vertical transmission is well documented but horizontal spread and the pathogenesis of abortion from this disease need further investigation. It is evident that, even with a very high probability of vertical transmission, some form of horizontal transmission is required for the disease to persist in a herd.

Incorporation of oxyethylene units between hydrocarbon chain and pseudoglyceryl backbone in cationic lipid potentiates gene transfection efficiency in the presence of serum

Four novel cationic lipids with different numbers of oxyethylene units at the linkage region between the pseudoglyceryl backbone and the hydrocarbon chains have been synthesized and used as mixtures with 1,2-dioleoyl-L-alpha-glycero-3-phosphatidyl ethanolamine (DOPE) for liposome-mediated gene transfection. Incorporation of different numbers of oxyethylene (-CH(2)CH(2)O-) units between long hydrocarbon chain at the C-1 and C-2 positions of the pseudoglyceryl skeleton improved the transfection efficiency considerably compared to the one in which the chains were connected via simple ether links. A pronounced improvement in the gene transfer efficiency was observed with the unsymmetrical cationic lipid 3 in which the long hydrocarbon at the C-1 position of the pseudoglyceryl segment is connected via two (-CH(2)CH(2)O-) units. Notably, the transfection ability of lipid 3 with DOPE in the presence of serum was significantly greater than LIPOFECTAMINE. This suggests that introduction of oxyethylene units between long hydrocarbon chains at the C-1 and C-2 positions of the pseudoglyceryl skeleton provides a novel strategy to achieve efficient gene transfer, especially in conditions where the presence of serum is critical.

Severe hypothermia with cardiac arrest: complete neurologic recovery in a 4-year-old child

A 4-year-old girl was lost for 17 hours in a snowstorm. Upon discovery, her core temperature was 72 degrees F (22 degrees C). While undergoing endotracheal intubation in the emergency department, she experienced sudden ventricular fibrillation and cardiac arrest. Closed chest cardiopulmonary resuscitation (CPR) was instituted, and standard rewarming measures were begun. Despite this, neither core temperature, nor the patient's arrhythmia, changed. An infraumbilical "mini-laparotomy" incision was made, with placement of a large silicone peritoneal dialysis catheter into the abdomen. This was then connected to a rapid infuser device, with the delivery of 1L of warmed, normal saline every 90 seconds. The core temperature reached 29 degrees C in 15 minutes, and a palpable pulse was detected. Lavage was continued until core temperature reached 34 degrees C, at which time transport to the pediatric intensive care unit was arranged. She was extubated the next day and discharged home, on the fourth hospital day, with apparent complete neurologic recovery. This is the first report of the successful use of rapid high-volume peritoneal lavage for the treatment of accidental severe hypothermia in a pediatric patient.

Bowel dysfunction following spinal cord injury

STUDY DESIGN

Review.

OBJECTIVES

To outline the present knowledge of bowel dysfunction following spinal injury, and look at future directions of management and research.

SETTING

Spinal Unit and Colorectal Unit, Christchurch, New Zealand.

METHODOLOGY

Review.

RESULTS

The underlying physiology of colorectal motility and defecation is reviewed, and consequences of spinal cord injury on defecation are reported. A discussion of present management techniques is undertaken and new directions in management and research are suggested.

CONCLUSION

There is need for more intervention in regard to bowel function that could improve quality of life, but there is also a need for more research in this area.

Improved version 2.0 qualitative and quantitative AMPLICOR reverse transcription-PCR tests for hepatitis C virus RNA: calibration to international units, enhanced genotype reactivity, and performance characteristics

Version 2.0 qualitative and quantitative AMPLICOR reverse transcription-PCR tests for HCV were designed to improve on the performance of first version of the hepatitis C virus (HCV) tests. The new tests were calibrated in international units, the new commonly accepted standard unit of measurement for HCV RNA. The sensitivity of the qualitative tests was enhanced by modifying the specimen processing procedure to achieve a limit of detection 50 IU/ml. The limit of detection for the quantitative tests was 600 IU/ml. Modifications to the amplification reaction mixture and thermal cycling conditions enabled all genotypes to be amplified with similar efficiency. The quantitative tests exhibited a linear range extending from 500 to 500,000 IU/ml and excellent reproducibility, with coefficients of variation ranging from 18 to 39%, within the linear range. These data indicate that the version 2. 0 AMPLICOR HCV tests will improve diagnosis of HCV infection and will yield more-accurate titers for prognosis and for monitoring therapeutic efficacy, particularly at low viral loads. Furthermore, it will be possible to compare the performance characteristics and viral load measurements of AMPLICOR tests to those of other tests that adopt the international unit as the standard of measurement.

Differential effects of tri-n-butylstannyl benzoates on induction of apoptosis in K562 and MCF-7 cells

Tributyltin compounds have been shown to induce apoptosis by causing extracellular Ca2+ influx and generating reactive oxygen species (ROS). Several organotin compounds were reported to have differential cytotoxicity on various human cell lines depending on the length of the alkyl chain. In this report, the cytotoxic effects of three tri-n-butylstannyl (halo)benzoate compounds-tri-n-butylstannyl benzoate (TBSB), tri-n-butylstannyl-2,6-difluorobenzoate (TBSDFB) and tri-n-butylstannyl-2-iodobenzoate (TBSIB)-were studied on lymphocytic cells of human leukemic K562 lineage and epithelial cells of human breast cancer MCF-7 cells lineage. K562 cells were found to be more sensitive to these compounds than MCF-7 cells. Although the induction of apoptosis by the above compounds in K562 cells resulted from the extracellular Ca2+ influx and the generation of ROS, the initial amount of extracellular Ca2+ influx was greater in TBSB-treated K562 cells than the cells treated with either TBSDFB or TBSIB. Similarly, DNA fragmentation by endonucleases was observed as an early event in TBSB-treated K562 cells, which might be correlated with the initially greater extracellular Ca2+ influx. In contrast, MCF-7 cells were found to undergo apoptosis mainly because of the generation of ROS. The present results suggest that the differential effects of tributyltin compounds on induction of apoptosis in K562 and MCF-7 cells are largely attributable to the extent of extracellular Ca2+ influx.

Azidothymidine induces apoptosis in mouse myeloma cell line Sp2/0

Azidothymidine (AZT), which has been extensively used as an antiviral agent in the treatment of AIDS, showed strong inhibition of growth of Sp2/0 cells in vitro. AZT-treated cells showed a decrease in viability in a dose-dependent manner. AZT specifically induced typical apoptotic cell death with DNA double-strand cleavage and subsequent formation of apoptotic bodies. The induction of DNA double-strand cleavage into the oligonucleosomal ladder by AZT was protected in the presence of thymidine or uridine. An increase in endonuclease activity from nuclear extract of AZT-treated cells was observed. The enzyme activity was found to be Ca(2+)-and Mg(2+)-dependent and was inhibited by zinc acetate. A marked enhancement of PARP activity was observed in AZT-treated cells. These observations show that AZT can trigger both morphological and biochemical changes typical of apoptosis in the mouse myeloma cell line Sp2/0.

Effect of nucleic acid reactive antibodies on tumor cells grown in vivo

Nucleic acid reactive antibodies have been reported to inhibit various nucleic acid mediated functions in cell free systems. These antibodies were also shown to inhibit the growth of transformed cells in culture due to the high rate of endocytosis in transformed cells as compared to normal cells. In this report, we have tested the possibility of nucleic acid reactive antibodies inhibiting the growth of tumor cells in vivo. The life span of mice bearing Dalton's lymphoma ascites tumor cells was increased, when they were immunized with conjugates of guanosine-BSA, GMP-BSA and tRNA-MBSA complex before transplanting the tumor cells. A similar effect was also observed when mice were injected intraperitoneally with antibodies to guanosine or GMP along with the tumor cells. The specificity was ascertained, as immunization with non-specific antigens did not show any significant effect on tumor bearing mice. The results shows that nucleic acid reactive antibodies inhibit the growth of tumor cells in vivo.

Antibodies raised against guanosine bind to double-stranded DNA

Antibodies elicited against guanosine have been reported to bind to single-stranded DNA. Using an avidin-biotin microELISA, we report that these antibodies also bind to double-stranded DNA. The binding is specific and is completely inhibited by the homologous hapten. The cross-reactivity of double-stranded DNA binding antibodies to single-stranded DNA is low. The antibodies are shown to bind to the topoisomers of plasmid DNA as assessed by a gel retardation assay.

Inhibition of in vitro aminoacylation and translation by RNA reactive antibodies

Antibodies were raised against guanosine-BSA, GMP-BSA and tRNA-mBSA conjugates separately in rabbits. Binding characteristics of these antibodies to various RNAs were studied using a sensitive avidin-biotin micro ELISA. These antibodies inhibited in vitro aminoacylation of tRNA in a dose dependent manner. This inhibition was reversed by the addition of the respective homologous haptens thereby showing the specificity of these antibodies. In vitro translation of endogenous mRNAs in rabbit reticulocyte lysate was also inhibited by these antibodies in a dose dependent manner.

Inhibition of in vitro transcription by adenosine antibodies

Antibodies against adenosine markedly inhibited in vitro transcription in isolated BHK 21 nuclei in a dose-dependent manner. The inhibition was specific as it could be completely reversed by the addition of homologous hapten. Addition of RNA at low concentration reversed the inhibition, whereas excess DNA did not have any effect. Adenosine antibodies also inhibited in vitro transcription with calf thymus DNA and E. coli RNA polymerase. Antibodies that react with DNA but not with RNA such as anti-dpA, anti-dpC and anti-DNA failed to inhibit in vitro transcription in isolated nuclei as well as with calf thymus DNA and E. coli RNA polymerase. The results strongly indicate that the binding of adenosine antibodies to RNA is responsible for the inhibition of transcription.

Base-specific binding of adenosine antibodies to double-stranded DNA

Antibodies raised against adenosine have been reported to react with single-stranded DNA but not with double-stranded DNA. Using a highly sensitive avidin-biotin microELISA we report that these antibodies also react with double-stranded DNA. The binding was specific as it was completely inhibited by the homologous hapten. The results indicate that the antibody populations binding to ssDNA and dsDNA are not cross-reactive. The antibodies were shown to react with the topoisomers of plasmid DNA as assessed by gel retardation assay. The antibodies showed differential binding to restriction fragments of DNA indicating that some of the A residues in dsDNA are accessible to the antibodies.

[The diagnostic value of so-called "post-cholecystectomy bile duct dilatation"]

In 1706 gallstone operations the diameter of the common bile ducts was determined in 990 cases during telecholangiography using a so-called functional cholangiodiametry. The data of 213 postoperative determinations of the common bile duct diameters performed during the follow-up period did not support the existence of a postcholecystectomic compensatoric dilation of the common bile duct. Ultrasound and ERCP failed to find postoperative bile duct dilation in patients without complaints following cholecystectomy and in persons with complaints of extrabiliary origin. In conclusion we found that biliopancreatic and organic reasons (residual calculi, papillary stenosis, bile duct stenosis, chronic pancreatitis) can always be detected as the underlying cause of a significant bile duct dilation.

Studies on hypomethylation of liver DNA during early stages of chemical carcinogenesis in rat liver

Our finding that the inhibitors of DNA methylation, 5-azacytidine, 5-azadeoxycytidine or adenosine dialdehyde, given after a carcinogen all potentiated initiation suggested that hypomethylation of DNA during repair synthesis of DNA might play a role in the initiation of the carcinogenic process. To examine this aspect further, we have asked the question, do the nodules which develop from initiated cells after promotion with 1% orotic acid exhibit an altered methylation pattern in their DNA? The methylation status of the DNA from nodules has been examined using the restriction endonucleases HpaII/MspI and HhaI which distinguish between methylated and unmethylated cytosines in their nucleotide recognition DNA 5'-CCGG and 5'-GCGC respectively. The proto-oncogenes, c-myc, c-fos and c-Ha-ras, in the DNA were primarily studied in this investigation because of their possible involvement in cell proliferation and/or in cell transformation and tumorigenesis. The results indicate that in the nodule DNA, c-myc and c-fos are hypomethylated in the sequence of CCGG while the c-Ha-ras shows hypomethylation in the alternating GCGC sequence. This methylation pattern seen in the nodule DNA is not found in the DNA of the non-nodular surrounding liver or liver tissue after exposure to promoter or carcinogen alone. It is also not found in the DNA of regenerating liver. It is particularly significant that the methylation patterns in the c-myc and c-Ha-ras regions are similar to those found in several cancer tissues. The results suggest that this methylation pattern is acquired early in the carcinogenic process and raises the question whether it has any bearing on the process.

Antibodies raised against denatured DNA bind to double-stranded DNA

Antibodies raised against denatured DNA complexed with methylated bovine serum albumin have been reported to react with ssDNA but not with dsDNA. Using a highly sensitive avidin-biotin microELISA, we report that such antibodies also bind to dsDNA. Antibodies which reacted with ssDNA and dsDNA were found to be of IgG type. The antibodies did not react with tRNA and rRNA. The binding of antibodies to dsDNA was partially inhibited by individual deoxyribonucleotides. ssDNA as well as dsDNA inhibited the binding of antibodies to dsDNA. The binding of these antibodies to supercoiled and relaxed forms of pBR322 DNA was demonstrated by gel retardation assay. The cross-reaction with ssDNA was observed even after affinity purification on native DNA-cellulose. The antibodies were also shown to bind to poly(dA-dT).poly(dA-dT).

Inhibition of in vitro amino acylation and translation by adenosine antibodies

Adenosine antibodies markedly inhibited in vitro amino acylation of tRNA in a dose-dependent manner. The inhibition was specific as it was reversed by the homologous hapten. Addition of excess tRNA reversed the inhibition indicating that binding of antibodies to tRNA is responsible for inhibition. Adenosine antibodies also inhibited in vitro translation of endogenous mRNAs in rabbit reticulocyte lysate in a dose-dependent manner. The homologous hapten reversed the inhibition showing thereby the immunospecificity of inhibition.

Binding of deoxyadenylate and deoxycytidylate antibodies to double-stranded DNA

Antibodies raised against deoxyadenylate and deoxycytidylate were found to react with double stranded DNA as assessed by highly sensitive avidin-biotin microELISA. The binding was specific as it was completely inhibited by the homologous hapten. The antibodies did not react with tRNA and rRNA. These antibodies were also shown to react with supercoiled and relaxed forms of pBR322 DNA as demonstrated by gel retardation assay.

Pharmacokinetics and chemotherapeutic efficacy of adriamycin encapsulated in immunoliposomes against avian myeloblastosis virus infection

Immunoliposomes were prepared using rabbit anti-AMV gp80 IgG for the targeted chemotherapy of avian myeloblastosis virus infection. Adriamycin was encapsulated into immunoliposomes and used for in vivo studies. Comparative pharmacokinetics of free drug, drug encapsulated in free liposomes and of drug encapsulated in immunoliposomes in the virus-infected cells revealed that (i) the drug encapsulated in liposomes was cleared from the plasma slowly, and (ii) the drug encapsulated in immunoliposomes accumulated in the target tissue, the bone marrow, 5- and 8.5-fold more than the drug encapsulated in free liposomes and free drug, respectively. The drug encapsulated in immunoliposomes inactivated the virus and exhibited more chemotherapeutic efficacy as compared to controls when injected up to 24 h post-infection. However, when injected 48 h post-infection the drug encapsulated in immunoliposomes did not offer any protection against the virus infection. There is no detectable antibody response against immunoliposomes in the infected animals.

Cytotoxic activity of daunomycin and adriamycin encapsulated in immunoliposomes against avian myeloblastosis virus-infected cells

Immunoliposomes were prepared using the antibody raised against the avian myeloblastosis virus envelope glycoprotein, gp80. Adriamycin was encapsulated into immunoliposomes. More drug was delivered into target cells when the drug encapsulated in immunoliposomes was incubated with the cells. The drug encapsulated in immunoliposomes was able to inhibit the RNA synthesis twice more than free drug in the virus-transformed myeloblasts. Pre-treatment of cells with ammonium chloride, reversed the effect of drug encapsulated in immunoliposomes. The drugs encapsulated in immunoliposomes had marginal effect on the RNA synthesis of non-target cells, the yolk sac cells. Colony formation by virus-transformed cells and focus formation by virus-infected yolk sac cells was inhibited significantly by the drug encapsulated in immunoliposomes.

Studies on the interaction of cupric isonicotinohydrazide with DNA

The interaction of cupric isonicotinohydrazide (CuIIINH), an antiviral compound, with calf thymus DNA was investigated by circular dichroism (CD) and nuclear magnetic resonance (NMR). Gel electrophoresis of DNA incubated with CuIIINH showed cleavage of DNA to various extents. This cleavage was found to be time and concentration dependent. In the presence of CuIIINH the positive CD band at 274 nm disappeared and the negative band at 246 nm showed a decrease in the mean residual ellipticity value, indicating binding of CuIIINH to DNA. 31P NMR studies indicated that the binding of copper in CuIIINH is to the phosphate oxygen of the DNA backbone. The binding of CuIIINH was also found to be reversible. Addition of ethylenediaminetetraacetic acid to the CuIIINH-DNA complex resulted in breaking of the complex and restoring the original structural features of the B family of DNA in the resulting fragments. At the concentration level of CuIIINH employed, both CuSO4 and INH independently did not show any interaction with DNA.

Liposome encapsulated subunit (VP1) and virion vaccines against foot-and-mouth disease

Subunit vaccine prepared from VP1 protein of foot-and-mouth disease virus (FMDV) types 0 and Asia 1 protected guinea pigs against FMD and also induced high levels of antibody. Liposomes have been used as a safe and potent immunological adjuvant for FMD vaccines. Vaccines prepared from inactivated virus types 0 and Asia 1 encapsulated in liposomes protected guinea pigs against challenge with homologous virus and showed good antibody response in pigs on a small scale field trial.

Comparative studies on growth of foot-and-mouth disease virus types 0 and Asia 1 in BHK-21 Razi cells

Growth pattern of foot-and-mouth disease virus types 0 and Asia 1 in BHK-21 Razi cells was compared; while type 0 virus grew in high titre, Asia 1 virus was produced in low titre. Inhibition of host protein synthesis in type 0 virus-infected cells was more pronounced than in Asia 1 virus-infected cells. Foot-and-mouth disease virus type 0 infected cells showed higher lactic dehydrogenase activity when compared to Asia 1 virus. A significant decrease in virus yield was observed when Actinomycin D had been added at 50 micrograms/ml to infected cells.