Effectiveness of testing, contact tracing and isolation interventions among the general population on reducing transmission of SARS-CoV-2: a systematic review

We conducted a systematic literature review of general population testing, contact tracing, case isolation and contact quarantine interventions to assess their effectiveness in reducing SARS-CoV-2 transmission, as implemented in real-world settings. We designed a broad search strategy and aimed to identify peer-reviewed studies of any design provided there was a quantitative measure of effectiveness on a transmission outcome. Studies that assessed the effect of testing or diagnosis on disease outcomes via treatment, but did not assess a transmission outcome, were not included. We focused on interventions implemented among the general population rather than in specific settings; these were from anywhere in the world and published any time after 1 January 2020 until the end of 2022. From 26 720 titles and abstracts, 1181 were reviewed as full text, and 25 met our inclusion criteria. These 25 studies included one randomized control trial (RCT) and the remaining 24 analysed empirical data and made some attempt to control for confounding. Studies included were categorized by the type of intervention: contact tracing (seven studies); specific testing strategies (12 studies); strategies for isolating cases/contacts (four studies); and 'test, trace, isolate' (TTI) as a part of a package of interventions (two studies). None of the 25 studies were rated at low risk of bias and many were rated as serious risk of bias, particularly due to the likely presence of uncontrolled confounding factors, which was a major challenge in assessing the independent effects of TTI in observational studies. These confounding factors are to be expected from observational studies during an on-going pandemic, when the emphasis was on reducing the epidemic burden rather than trial design. Findings from these 25 studies suggested an important public health role for testing followed by isolation, especially where mass and serial testing was used to reduce transmission. Some of the most compelling analyses came from examining fine-grained within-country data on contact tracing; while broader studies which compared behaviour between countries also often found TTI led to reduced transmission and mortality, this was not universal. There was limited evidence for the benefit of isolation of cases/contacts away from the home environment. One study, an RCT, showed that daily testing of contacts could be a viable strategy to replace lengthy quarantine of contacts. Based on the scarcity of robust empirical evidence, we were not able to draw any firm quantitative conclusions about the quantitative impact of TTI interventions in different epidemic contexts. While the majority of studies found that testing, tracing and isolation reduced transmission, evidence for the scale of this impact is only available for specific scenarios and hence is not necessarily generalizable. Our review therefore emphasizes the need to conduct robust experimental studies that help inform the likely quantitative impact of different TTI interventions on transmission and their optimal design. Work is needed to support such studies in the context of future emerging epidemics, along with assessments of the cost-effectiveness of TTI interventions, which was beyond the scope of this review but will be critical to decision-making. This article is part of the theme issue 'The effectiveness of non-pharmaceutical interventions on the COVID-19 pandemic: the evidence'.

Effectiveness and safety of tenofovir alafenamide in children and adolescents living with HIV: a systematic review

INTRODUCTION

Tenofovir alafenamide (TAF) is approved for paediatric use in fixed-dose combination tablets, but efficacy and safety data in children are limited. We conducted a systematic review on the efficacy/effectiveness and safety of TAF in infants, children and adolescents living with HIV.

METHODS

We searched MEDLINE, Embase, the Cochrane Library, clinical trial registries, reference lists and relevant conferences to identify literature published January 2009-March 2021. We included clinical trials and observational studies assessing the efficacy/effectiveness or safety of TAF through ≥6 months of treatment in participants aged 0-19 years.

RESULTS AND DISCUSSION

Overall 3626 abstracts and 371 full papers were screened. Four single-arm, innovator-funded trials (341 participants) and a pooled analysis of those trials were identified. All four trials included treatment-experienced and virally suppressed children or adolescents. One trial also included treatment-naïve adolescents with baseline viral load >1000 copies/ml. The risk of bias was rated as low in one study and unclear in the other three owing to missing data on study design (all conference presentations). At 48 weeks, 92% (46/50) of treatment-naïve participants were virally suppressed (one trial). Among treatment-experienced participants with viral load at 48 weeks, 214 of 224 participants were virally suppressed. Across the studies, one grade 3/4 adverse event was considered drug-related (intermediate uveitis). There were three discontinuations for adverse events (grade 2 anxiety and insomnia, grade 1 iridocyclitis [drug-related] and grade 1 pulmonary tuberculosis [unrelated to treatment]). One accidental death occurred across the four studies. In the pooled analysis of 223 participants, the median change in bone mineral density z-score (height- and age-adjusted) from baseline to 48 weeks was -0.12 (interquartile range [IQR] -0.46, 0.17) to 0.05 (IQR not reported) for spine, and -0.09 (IQR -0.33, 0.07) to 0.09 (IQR not reported) for total body less head. Weight-for-age z-scores increased by 0.25 from baseline to 48 weeks.

CONCLUSIONS

Four single-arm trials were identified in this systematic review, with initial evidence suggesting good viral suppression and no obvious safety concerns in children and adolescents on TAF-containing regimens over 24-48 weeks. However, further comparative and longer-term safety data are needed in children and adolescents, including on weight and metabolic changes.

Effectiveness and safety of dolutegravir and raltegravir for treating children and adolescents living with HIV: a systematic review

INTRODUCTION

Globally about 1.7 million children were living with HIV in 2020. Two integrase strand transfer inhibitors, dolutegravir and raltegravir, are increasingly used in children. We conducted a systematic review to assess the effectiveness and safety of dolutegravir and raltegravir in children and adolescents living with HIV, aged 0-19 years.

METHODS

Sources included MEDLINE, Embase, the Cochrane Library, clinical trial registries, abstracts from key conferences and reference list searching. Observational studies and clinical trials published January 2009-March 2021 were eligible. Outcomes included efficacy/effectiveness (CD4 counts and viral load) and/or safety outcomes (mortality, grade 3/4 adverse events and treatment discontinuation) through 6 months or more post-treatment initiation. Risk of bias was assessed using previously published tools appropriate for the study design. Narrative syntheses were conducted.

RESULTS AND DISCUSSION

In total, 3626 abstracts and 371 papers were screened. Eleven studies, including 2330 children/adolescents, reported data on dolutegravir: one randomized controlled trial (RCT; low risk of bias), one single-arm trial (unclear risk of bias) and nine cohort studies (three low risk of bias, two unclear risk and four high risk). Ten studies, including 649 children/adolescents receiving raltegravir, were identified: one RCT (low risk of bias), one single-arm trial (low risk of bias) and eight cohort studies (four low risk of bias, three unclear risk and one high risk). Viral suppression levels in children/adolescents at 12 months were high (>70%) in most studies assessing dolutegravir (mostly second- or subsequent-line, or mixed treatment lines), and varied from 42% (5/12) to 83% (44/53) at 12 months in studies assessing raltegravir (mostly second- or subsequent-line). Across all studies assessing dolutegravir or raltegravir, grade 3/4 adverse events (clinical and/or laboratory) were reported in 0-50% of subjects, few resulted in discontinuation, few were drug related and no deaths were attributed to either drug.

CONCLUSIONS

These reassuring findings suggest that dolutegravir and raltegravir are effective and safe as preferred regimens in children and adolescents living with HIV. With the rollout of dolutegravir in paediatric populations already underway, it is critical that data are collected on safety and effectiveness in infants, children and adolescents, including on longer-term outcomes, such as weight and metabolic changes.

Effectiveness and Safety of Atazanavir Use for the Treatment of Children and Adolescents Living With HIV: A Systematic Review

BACKGROUND

Atazanavir/ritonavir is recommended as a preferred second-line antiretroviral regimen in children older than 3 months, alternatively to lopinavir/ritonavir. We performed a systematic review to assess safety and effectiveness of atazanavir use in children and adolescents.

METHODS

We searched observational studies and clinical trials on Web of Science, Embase and Cochrane CENTRAL database between 2009/01/01 and 2020/10/01; as well as grey literature. We extracted safety (adverse events, grade 3 or 4 adverse events, treatment discontinuation) and effectiveness (CD4 cell counts and HIV viral load) outcomes. We estimated weighted summary pooled incidence with corresponding 95% confidence intervals.

RESULTS

Out of the 1,085 records screened, we included five studies (one comparative cohort, three single phase 2-3 trial arms, one retrospective cohort) reporting 975 children and adolescents, of whom 56% (544) received atazanavir. Three studies reported all-cause treatment discontinuation rates, yielding a pooled incidence of 19% [15-22] at 12 months. The comparative cohort compared atazanavir to darunavir, with few grade 3-4 adverse events, except transient hyperbilirubinemia, occurring in half (92/188) of the atazanavir patients. No death occurred (two studies reporting). Four studies described increased CD4 cell counts and decreased HIV viral load at 6 or 12 months.

CONCLUSION

Few safety and effectiveness data were available for children and adolescents exposed to atazanavir. Transient grade 3-4 hyperbilirubinemia was the main adverse outcome reported. Immune and viral responses were descriptive. The use of atazanavir/ritonavir in children and adolescents needs further investigation, but remains a suitable option for a preferred second-line antiretroviral regimen.

PROSPERO NUMBER

CRD42022309230.

BET 1: Everything in graduation: arterial/end-tidal CO2 gradient and the diagnosis of pulmonary embolism

A short cut review was carried out to establish the diagnostic characteristics of alveolar dead space fraction (AVDSf) in the diagnosis of pulmonary embolism (PE). This is calculated from the arterial and end-tidal CO₂ Three papers were selected to answer the clinical question. The author, study type, relevant outcomes, results and weaknesses are tabulated. It is concluded that there is good evidence to support the use of AVDSf within a clinical prediction model to exclude a PE in patients when there is a low pretest probability. However, the specificity is not sufficient to support it as a 'rule in' test.

The IDENTIFY study: the investigation and detection of urological neoplasia in patients referred with suspected urinary tract cancer - a multicentre observational study

OBJECTIVE

To evaluate the contemporary prevalence of urinary tract cancer (bladder cancer, upper tract urothelial cancer [UTUC] and renal cancer) in patients referred to secondary care with haematuria, adjusted for established patient risk markers and geographical variation.

PATIENTS AND METHODS

This was an international multicentre prospective observational study. We included patients aged ≥16 years, referred to secondary care with suspected urinary tract cancer. Patients with a known or previous urological malignancy were excluded. We estimated the prevalence of bladder cancer, UTUC, renal cancer and prostate cancer; stratified by age, type of haematuria, sex, and smoking. We used a multivariable mixed-effects logistic regression to adjust cancer prevalence for age, type of haematuria, sex, smoking, hospitals, and countries.

RESULTS

Of the 11 059 patients assessed for eligibility, 10 896 were included from 110 hospitals across 26 countries. The overall adjusted cancer prevalence (n = 2257) was 28.2% (95% confidence interval [CI] 22.3-34.1), bladder cancer (n = 1951) 24.7% (95% CI 19.1-30.2), UTUC (n = 128) 1.14% (95% CI 0.77-1.52), renal cancer (n = 107) 1.05% (95% CI 0.80-1.29), and prostate cancer (n = 124) 1.75% (95% CI 1.32-2.18). The odds ratios for patient risk markers in the model for all cancers were: age 1.04 (95% CI 1.03-1.05; P < 0.001), visible haematuria 3.47 (95% CI 2.90-4.15; P < 0.001), male sex 1.30 (95% CI 1.14-1.50; P < 0.001), and smoking 2.70 (95% CI 2.30-3.18; P < 0.001).

CONCLUSIONS

A better understanding of cancer prevalence across an international population is required to inform clinical guidelines. We are the first to report urinary tract cancer prevalence across an international population in patients referred to secondary care, adjusted for patient risk markers and geographical variation. Bladder cancer was the most prevalent disease. Visible haematuria was the strongest predictor for urinary tract cancer.

Abstract 3251: Assessment of NK cell-mediated killing and phenotypic analysis using advanced flow cytometry and an optimized multiplexed assay

In this study, a novel multiplexed assay was developed that simultaneously measures NK cell phenotype and function in relation to tumor target killing. Natural Killer (NK) cells are an essential part of the innate immune system, interface with the adaptive immune system, and play a critical role in tumor immune surveillance and anti-tumor responses. Although chimeric antigen receptor (CAR)-modified T cells have proven to be highly effective as an anti-cancer therapeutic, there are potential problems associated with their use, particularly the risk of inducing graft-versus-host disease (GVHD) resulting in aberrant cytokine release. In contrast to T cells, NK cells are potent cytotoxic effector cells that do not require MHC restriction and have a low risk of inducing GVHD. Recent advances in the development of CAR-modified NK cells have shown great promise for clinical utilization in cancer immunotherapy with capability for both direct tumor killing as well as for use in combination therapy with monoclonal antibodies to boost NK cell antibody-dependent cell-mediated cytotoxicity (ADCC). A critical process in the development of new NK cell-mediated therapeutics is the ability to expediently assay, screen, and analyze data for NK cell activation and tumor killing. To address this need, a novel multiplexed assay was developed that measures tumor target cell killing, target-dependent expression of activation markers (CD69 and CD25), and the quantitation of secreted granzyme B, IFNγ, and TNFα in a single well of a microtiter plate. To validate the assay, a direct NK cell-tumor cell killing model was used. Purified human NK cells were mixed with target cells at different ratios. Tumor cell killing, NK cell activation status, and quantification of secreted proteins were measured at 4 and 24 hours after co-culture. Assay data acquisition was performed on Intellicyt iQue3® platform for advanced flow cytometry. Data analysis and visualization was performed using the integrated ForeCyt® software package. Tumor cell killing along with granzyme B release, was evident by 4 hours following co-culture, and both were increased with the increase in effector to target ratio (E:T). Killing was further enhanced when NK cells were stimulated with IL-2 and IL-15. As expected, an increase in CD69 and CD25 expression was also observed following cytokine stimulation with further increase upon co-culture of NK cells with tumor cell targets, along with increased levels of secreted IFNγ and TNFα. Further validation of the assay using an ADCC model was also performed. These data show that a miniaturized, multiplexed NK cell killing assay, combined with high throughput flow cytometry, is a powerful tool to rapidly screen CAR-NK cell effector functions and other NK cell based therapeutics.

Citation Format: Julie Lovchik, Sarita Chauhan, John O'Rourke. Assessment of NK cell-mediated killing and phenotypic analysis using advanced flow cytometry and an optimized multiplexed assay [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3251.

Systematic literature review of the global burden of illness of mantle cell lymphoma

Background: Mantle cell lymphoma (MCL), a rare and aggressive disease, accounts for approximately 5% of all B-cell non-Hodgkin's lymphomas. Evidence on the burden of this disease, for patients and healthcare providers, is scarce.Methods: Four systematic literature reviews were developed to identify epidemiological, real-world clinical, economic and humanistic burden data on patients with MCL. Electronic databases searched included MEDLINE and Embase, NHS EED and Econlit.Results: Eight epidemiological studies, 19 clinical burden, 2 economic impact and 0 quality of life studies were identified. The range of standardized MCL incidence rates was 0.1-1.27/100,000. Overall survival rates of patients at 3 years differed by age at diagnosis (≤65 years: 76-81%, >65 years: 46-64%) and disease stage (stage I: 73-80%, stage IV: 48-53%). Outcomes were poorer in previously treated patients, and those with later stage or blastoid disease, and improved with more recent diagnosis/treatment. Hospitalization is a major contributor to healthcare cost and differs by therapy toxicity.Conclusions: We identified significant data gaps for many G20 countries for epidemiology, real-world clinical, economic and humanistic burden. These literature reviews demonstrate the ongoing unmet need for MCL patients globally. Future research to further understand the real-world impact of MCL is needed along with new therapeutic options to improve patient outcomes.

They're always there for me! Friendship and meaning in young people's lives?

What gives individuals’ lives meaning is one of the bigger questions confronted by community members? Making sense of our lives and determining what it is that provides us with direction, strength, or commitment is no simple task and even more so in western consumerist societies where so many experiences appear accessible. Finding ways to elicit thoughtful responses from research participants, has led to varied approaches to this increasingly rich research area. An encouraging method is to use digital photography to extract information on what it is that captures participants’ ‘mind's eye’ when reflecting on meaning in their lives. In this article, a pilot study using a combination of digital photography and descriptive narratives was established to explore the thoughts of 174 year seven students in a private West Australian school on what provided their lives with meaning both in school and outside of school. The photos and narratives were explored for themes and while many categories were identified, it was apparent that relationships were the strongest source of meaning in their lives.

Randomized controlled study of the prediction of diminutive/small colorectal polyp histology using didactic versus computer-based self-learning module in gastroenterology trainees

BACKGROUND AND AIM

The aim of this randomized trial was to evaluate the performance of self-training versus didactic training in order to increase the diagnostic accuracy of diminutive/small colonic polyp histological prediction by trainees.

METHODS

Sixteen trainees reviewed 78 videos (48 iSCAN-OE and 30 NBI) of diminutive/small polyps in a pretraining assessment. Trainees were randomized to receive computer-based self-learning (n = 8) or didactic training (n = 8) using identical teaching materials and videos. The same 78 videos, in a different randomized order, were assessed. The NICE (NBI International Colorectal Endoscopic) and SIMPLE (Simplified Identification Method for Polyp Labeling during Endoscopy) classification systems were used to classify diminutive/small polyps.

RESULTS

A higher proportion of high-confidence predictions of polyps was made by the self-training group versus the didactic group using both the SIMPLE classification (77.1% [95% CI 73.4-80.3] vs 69.9% [95% CI 66.1-73.5%] [P = 0.005]) and the NICE classification (77% [95% CI 73.2-80.4%] vs 69.8% [95% CI 66-73.4%] [P = 0.006]). When using NICE, sensitivity of the self-training group compared with the didactic group was 72% versus 83% (P = 0.0005), and the accuracy was 66.1% versus 69.1%. The training improved the confidence of participants and SIMPLE was preferred over NICE.

CONCLUSION

Self-learning for the prediction of diminutive/small polyp histology is a method of training that can achieve results similar to didactic training. Availability of adequate self-learning teaching modules could enable widespread implementation of optical diagnosis in clinical practice.

Abstract 1209: Screening ex vivo conditions that increase memory T cell frequency using high throughput flow cytometry and an optimized multiplexed assay

A critical process in bio-manufacturing of adoptive cell therapies such chimeric antigen receptor (CAR) T and tumor infiltrating lymphocyte (TIL) therapies is the ex vivo expansion of T cells. Recent clinical studies show a correlation between in vivo expansion and persistence of infused T cells and patient outcomes. Additional studies show that a subset of functional memory T cells including T memory stem cells (Tscm) and central memory T cells (Tcm) are responsible for the majority of in vivo expansion and persistence leading to increased anti-tumor responses. This suggests that ex vivo protocols generating higher percentages of Tscm and Tcm in the total cell product will lead to significant clinical improvements.

We developed a robust, high-content T cell memory assay to address monitoring requirements for T cell phenotype and function for improved ex vivo expansion protocols and other studies where profiling of memory subsets is crucial. This miniaturized assay uses high throughput flow cytometry to measure cell phenotype, cell viability and effector cytokine release in the same sample well of a 96- or 384-well microtiter plate. The optimized antibody panel includes markers to identify T cells (CD3, CD4, and CD8); markers to discriminate between naive, memory, effector subsets (CD45RA, CD45RO, CD62L, and CD95); and a long-term survival marker (CD27). In addition, secreted cytokine quantitation (INFγ and IL-10) is performed simultaneously with the phenotypic and cell health measurements using a bead-based assay.

Proof of concept studies were performed by stimulating peripheral blood mononuclear cells (PBMC) from multiple donors using anti-CD3/anti-CD28 coated beads. Activated T cells were expanded by culturing in serum-free media supplemented with different combinations and concentrations of IL-4, IL-7, IL-15, and IL-21 in a 96-well plate format. On Days 3 through 7 post stimulation, a small aliquot from each culture well was transferred to an assay plate and assessed for phenotype and function using the T cell memory assay. Data were acquired using the Intellicyt iQue Screener PLUS® VBR high throughput flow cytometer and analyzed using the integrated ForeCyt® software package. These data showed that the various cytokine combinations had a distinct effect on promoting T cell memory frequency, especially the Tscm cell subset, as well as effector cytokine secretion in a temporal and concentration specific manner.

These data show the T cell memory assay, combined with high throughput flow cytometry, is a powerful tool to rapidly screen for cytokine combinations that increase the frequency of T-memory cells during ex vivo expansion of T-cell products. Besides their use in optimizing cell manufacturing protocols, these tools can be easily applied to the profiling of other biologics and drugs where the monitoring of T cell memory subsets is required.

Citation Format: Zhaoping Liu, Andrea Donart-Gomez, John O'Rourke. Screening ex vivo conditions that increase memory T cell frequency using high throughput flow cytometry and an optimized multiplexed assay [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1209.

Abstract 4648: Using the IntelliCyt iQue Screener to simultaneously profile antibody dependent cell cytotoxicity and cytokine release of therapeutic antibodies

Therapeutic antibodies can mediate cancer cell killing through a variety of mechanisms including antibody dependent cell-mediated cytotoxicity (ADCC), antibody dependent cellular phagocytosis (ADCP) and complement dependent killing (CDC). ADCC is induced through the binding of the antibody Fc region to Fc receptors (FcRs) expressed on effector cells of the immune system. Granule exocytosis of perforin, granzyme B, the induction of Fas ligand (FasL) expression on immune cells and the release of cytokines are major mechanisms involved in targeted cancer cell killing.

Traditional approaches to screen for antibody Fc effector functions focus on ADCC using a homogenous live/dead readout, which greatly limits the contextual and correlative value of the screening data. To overcome this limitation, a multiplex screening assay profiling ADCC using multiple cell death endpoints, and quantitating secreted proteins /cytokines was developed and analyzed using Intellicyt's iQue Screener PLUS and integrated ForeCyt software. The iQue Screener Plus is a high throughput flow cytometry platform featuring 3 lasers with 13 fluorescent channels and can sample a 384-well plate in 20 minutes.

As a proof of concept, a small set of therapeutic antibodies directed against the same tumor antigen were used to induce immune cell-mediated killing of tumor cells using different effector to target cell ratios and a range of antibody concentrations. To demonstrate antibody specificity, antigen positive target cells, negative control target cells and effector immune cells were barcoded with different encoding dyes and included in the same well. At specific times, a small aliquot from each well was transferred to a new assay plate to run a multiplexed cell/bead mixture assay by the addition of a cocktail of fluorescent immunophenotyping antibodies, fluorescent dyes measuring unique apoptosis parameters, and a panel of QBeads for secreted protein detection. The samples were assayed on the IntelliCyt iQue Screener PLUS with simultaneous data analysis including multi-plate analysis for cell killing kinetics. Positive/negative target cells and immune cells were digitally segregated by differently encoded fluorescence. Time-dependent cell killing of antigen positive target cells were observed using the apoptosis markers mitochondria depolarization staining and cell membrane integrity, whereas little killing was measured in antigen negative cells. The antibody set showed a range of ADCC mediated killing and granule exocytosis/ cytokine release suggesting differences in Fc effector functions. These results highlight the streamlined workflow on IntelliCyt iQue Screener PLUS platform to profile therapeutic antibodies in a functional ADCC/cytokine release assay predicting their clinical efficacy.

Citation Format: John O'Rourke. Using the IntelliCyt iQue Screener to simultaneously profile antibody dependent cell cytotoxicity and cytokine release of therapeutic antibodies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4648.

Abstract 5572: AX09: an immunotherapy candidate targeting the breast cancer stem cell protein xCT

Triple negative breast cancer (TNBC) is an aggressive form of breast cancer that lacks the estrogen, progesterone and HER2 receptors, and accounts for 15-20% of all breast cancers in the US. The particularly aggressive features of TNBC may be due to the enrichment of breast cancer stem cells (BCSC). Due to their resistance to traditional radio- and chemo-therapies, BCSC represent a reservoir for the relapse, metastatic evolution and progression of the disease after treatment. Therefore, successful eradication of BCSC represents a major barrier towards effective cancer treatments.

The ability of BCSC to resist common cytotoxic therapies relies on different mechanisms, including improved detoxification ability. The cystine-glutamate antiporter protein xCT (SLC7A11) regulates cystine intake, conversion to cysteine and subsequent glutathione synthesis, protecting cells against oxidative and chemical insults via the p38MAPK pathway. xCT expression is highly restricted to a few normal cell types but is upregulated in a variety of breast cancer subtypes where its expression correlates with poor prognosis. xCT is highly expressed in a variety of solid tumor CSC including BCSC where it interacts with CD44 and plays a functional role in BCSC biology.

Agilvax has developed a novel immunotherapy candidate (AX09) based on our virus-like-particle technology for the treatment and prevention of metastatic breast cancer that targets the BCSC protein xCT. Immunization with AX09 elicited a strong antibody response against xCT including high levels of IgG2a antibody. Immune sera from AX09 mice bound to tumorsphere derived BCSC and impacted BCSC function and biology in vitro. To assess if AX09 immunization would decrease metastases, we employed a syngeneic transplantation model, in which purified BCSC derived from TUBO cells were injected into the tail vein of vaccinated female BALB/c mice. Multiple independent experiments showed that immunization with AX09 conferred a significant reduction in the number of pulmonary metastases compared to vaccination with control VLP alone. In a pilot study, BCSC were transplanted into the mammary fat pad and mice were treated with AX09 after primary tumors were 1.5 mm in diameter. Results indicate that AX09 immunization conferred a reduction in lung metastases compared to controls.

These data show that an active immunization approach targeting xCT can significantly reduce metastatic progression in preclinical models. Ongoing experiments are further characterizing therapeutic mechanisms and evaluating efficacy of AX09 in combination with front line chemotherapy and checkpoint inhibitors.

Citation Format: John O'Rourke, Elisabett Bolli, Valeria Rolih, Laura Conti, Stefania Lanzardo, Jayne Christen, Federica Pericle, Federica Cavallo. AX09: an immunotherapy candidate targeting the breast cancer stem cell protein xCT [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5572. doi:10.1158/1538-7445.AM2017-5572

Patient selection essential for computed tomography coronary angiography

OBJECTIVE

Computed tomography coronary angiography (CTCA) has become a commonly used imaging modality in patients with suspected anginal symptoms but also in asymptomatic populations. This practice has raised concerns due to potential high radiation exposure in terms of adequate benefit to risk profile.

DESIGN

Demographics and CTCA scan details were collected from a consecutive series of 586 patients referred to a single community radiology practice for a CTCA.

RESULTS

Of the 586 patients, 271 (46.2%) were women. Mean age was 58.3 standard deviation (SD) 12.2, range 15-90 years, body mass index (BMI) 28.6 SD 5.9 kg/m(2), and heart rate 60 SD 10 beats per minute. Mean total radiation was 4.79 SD 3.45 mSv (range 0.64-31.34). The mean radiation exposure in the lowest quartile of BMI and heart rate were 3.01 SD 1.84 mSv and 3.95 SD 2.72 mSv, compared to the highest 7.32 SD 3.51 mSv and 6.20 SD 4.38 mSv (p for trend <0.0001 in both).

CONCLUSION

The radiation exposure in this consecutive series of patients is low in general but patient selection for CTCA imaging appears to be paramount. Patients with a high BMI and especially with high heart rate receive a higher dose of radiation.

The Role of Speech and Language Therapy in Assessing and Managing Pharyngo-esophageal Diverticula

This study explores the contribution of Speech and Language Therapists (SLTs) to the assessment and management of patients presenting on videofluoroscopic swallow studies (VFSS) with a suspected pharyngo-oesophageal diverticulum. Records for all patients who attended for VFSS in an acute hospital over an eleven-year period were examined (N = 1820). Twenty patients were identified on VFSS as having a suspected diverticulum. Symptoms suggestive of a diverticulum were found during both bedside clinical examination and radiographic examination e.g. respiratory difficulties (n = 15; 75%), voice changes (n = 14; 70/0). VFSS confirmed a reduced risk of aspiration for 14 patients (70%) using a combination of fluid modification (n = 9; 45%), food modification (n = 13; 65%) and swallow strategies (n = 14; 70%). VFSS confirmed aspiration directly related to the diverticulum in 11 patients (55%). Findings indicate that SLTs have the opportunity to identify potential diverticula and implement behavioural management to reduce associated health risks. This is of particular importance to patients who are awaiting, or cannot undergo, surgical repair of their diverticulum.

External fluorescence retention of calcein-marked juvenile brown trout Salmo trutta raised in natural and artificial environments

The fluorescence retention and intensity of juvenile brown trout Salmo trutta marked during their first summer were monitored in a hatchery and in four natural streams. A handheld detector was used for direct examination. In the hatchery, three marking treatments (T) were compared: 3·5 min in a 0·5% calcein solution (T0·5-3·5), 7 min in a 0·5% calcein solution (T0·5-7) and 3·5 min in a 1% calcein solution (T1-3·5). The fish were raised indoors for 11 months and then outdoors until 18 months. The fluorescence retention rate was 100% in all treatments at 11 months, although T1-3·5 showed the highest mean fluorescence intensity, followed by T0·5-7 and T0·5-3·5. The fluorescence intensity was not correlated with the final total length (L(T)) of the fish in two treatments, although it significantly decreased with increasing L(T) in T1-3·5. At 18 months, <30% of the fish were still slightly fluorescent, suggesting a negative effect of sunlight exposure. In stream studies, the fluorescence intensity did not significantly differ according to final L(T); an overall mean ± s.d. retention rate of 70·7 ± 26·6% was measured at 12 months with a decrease to 48·6 ± 24·6% at 24 months. Significant differences amongst streams and within reaches of the same stream were observed. Because of a significant positive effect of the shading index on the fluorescence intensity, the use of calcein should be restricted to streams unexposed to direct sunlight. Consequently, the marking method would be reliable for 1 year monitoring studies in shaded streams.

Organ donation following the circulatory determination of death (DCD): an audit of donation and outcomes following renal transplantation

Organ Donation following the Circulatory determination of Death was introduced in Beaumont Hospital during 2011. The Intensive Care Society of Ireland formally endorsed a national DCD clinical practice guideline in 2012. This retrospective audit covers a 2-year period during which eleven patients were considered suitable for DCD and where consent was obtained. Nine patients died within the ninety-minute period following the withdrawal of life sustaining therapies and subsequently donated organs (82%). Eighteen kidneys were recovered and seventeen patients received renal transplants--one patient received a nephron-dosing dual renal transplant. Lungs were recovered on two occasions and one patient received a lung transplant. Heart valves were recovered on one occasion. To date sixteen of seventeen recipient patients have functioning renal transplants (94%). In conclusion, this model of deceased donation has proven acceptable to families, nursing and medical staff and the outcomes reported are consistent with international best practice.

Non heart beating organ donation in adults: a clinical practice guideline

Non heart beating organ donation (NHBD) occurs when a patient donates organs following the determination of death by cardiorespiratory criteria. It is also know as Donation after Cardiac Death (DCD) or Donation after Circulatory Death (DCD). This is distinct from Donation after Brainstem Death (DBD), which until 2011, accounted for all cadaveric organs (organ from deceased persons) donated within the Republic of Ireland. NHBD is an important initiative that has the potential to be life-saving. When compared to international protocols, the NHBD protocol at Beaumont Hospital is both conservative and restrictive. It offers an alternative when conditions of brainstem death (BSD) cannot be satisfied and, since implementation a number of successful transplants have been performed from NHB donors.

Dlk1 is a negative regulator of emerging hematopoietic stem and progenitor cells

The first mouse adult-repopulating hematopoietic stem cells emerge in the aorta-gonad-mesonephros region at embryonic day (E) 10.5. Their numbers in this region increase thereafter and begin to decline at E12.5, thus pointing to the possible existence of both positive and negative regulators of emerging hematopoietic stem cells. Our recent expression analysis of the aorta-gonad-mesonephros region showed that the Delta-like homologue 1 (Dlk1) gene is up-regulated in the region of the aorta-gonad-mesonephros where hematopoietic stem cells are preferentially located. To analyze its function, we studied Dlk1 expression in wild-type and hematopoietic stem cell-deficient embryos and determined hematopoietic stem and progenitor cell activity in Dlk1 knockout and overexpressing mice. Its role in hematopoietic support was studied in co-culture experiments using stromal cell lines that express varying levels of Dlk1. We show here that Dlk1 is expressed in the smooth muscle layer of the dorsal aorta and the ventral sub-aortic mesenchyme, where its expression is dependent on the hematopoietic transcription factor Runx1. We further demonstrate that Dlk1 has a negative impact on hematopoietic stem and progenitor cell activity in the aorta-gonad-mesonephros region in vivo, which is recapitulated in co-cultures of hematopoietic stem cells on stromal cells that express varying levels of Dlk1. This negative effect of Dlk1 on hematopoietic stem and progenitor cell activity requires the membrane-bound form of the protein and cannot be recapitulated by soluble Dlk1. Together, these data suggest that Dlk1 expression by cells of the aorta-gonad-mesonephros hematopoietic microenvironment limits hematopoietic stem cell expansion and is, to our knowledge, the first description of such a negative regulator in this tissue.

An evaluation of the Cortrak Enteral access system in our intensive care

Appropriate nutrition is considered a cornerstone of Intensive care; however its successful initiation is frequently impeded by decreased gastric emptying secondary to opiates, sepsis, or ileus. The presence of a postpyloric tube will guarantee delivery of calories while reducing the incidence of reflux and aspiration. Enteral nutrition is approximately 100 fold cheaper than parenteral nutrition. A nasojejunal tube may be placed blindly (success 15%), by direct vision with a gastroscope, or under fluoroscopic guidance in the X-ray department. This study examines the use of the Cortrak Enteral access system (CEAS) in placement of nasojejunal tubes, a method facilitated by the use of an electromagnet. A retrospective review was conducted to evaluate the effectiveness of the CEAS for establishing nasojejunal feeding in the Intensive Care Unit (ICU) between January and December 2010. Our results found that the CEAS was successful in positioning a nasojejunal tube in ten out of twelve patients (83% success rate). Successful placement was confirmed by portable abdominal / chest x-ray. Placement took an average of 30 minutes, and prokinetic agents were used to facilitate two placements. The duration of successful enteral nutrition varied from 2 to 15 days post placement. The CEAS is a simple bedside tool for placing postpyloric tubes. While there is a learning curve associated with its use, it may confer significant benefits to individual patients and also to those responsible for ever shrinking budgets.

Extra-corporeal membrane oxygenation in the management of 2009 influenza A (H1N1) refractory respiratory failure

Rapidly progressive acute respiratory failure attributed to 2009 H1N1 influenza A infection has been reported worldwide-3. Refractory hypoxaemia despite conventional mechanical ventilation and lung protective strategies has resulted in the use a combination of rescue therapies, such as conservative fluid management, prone positioning, inhaled nitric oxide, high frequency oscillatory ventilation and extracorporeal membrane oxygenation (ECMO)4. ECMO allows for pulmonary or cardiopulmonary support as an adjunct to respiratory and cardiac failure, minimising ventilator-associated lung injury (VALI). This permits treatment of the underlying disease process, while concurrently allowing for recovery of the acute lung injury. This case documents a previously healthy twenty-two year old Asian male patient with confirmed pandemic (H 1N1) 2009 influenza A who was successfully managed with ECMO in the setting of severe refractory hypoxaemia and progressive hypercapnia.

Effects of sequential changes from conventional ventilation to high-frequency oscillatory ventilation at increasing mean airway pressures in an ovine model of combined lung and head injury

BACKGROUND

The objective of this study was to determine the intracranial, cardiovascular and respiratory changes induced by conversion to high-frequency oscillator ventilation from conventional mechanical ventilation at increasing airway pressures.

METHODS

In this study, 11 anaesthetized sheep had invasive cardiovascular and intracranial monitors placed. Lung injury was induced by saline lavage and head injury was induced by inflation of an intracranial balloon catheter. All animals were sequentially converted from conventional mechanical ventilation to high-frequency oscillator ventilation at target mean airway pressures of 16, 22, 28, 34 and 40 cm H(2)O. The mean airway pressure was achieved by adjusting positive end expiratory pressure while on conventional mechanical ventilation, and continuous distending pressures while on high-frequency oscillator ventilation. Cerebral lactate production, oxygen consumption and venous oximetry were measured and analysed in relation to changes in transcranial Doppler flow velocity. Transcranial Doppler profiles together with other physiological parameters were measured at each airway pressure.

RESULTS

Cerebral perfusion pressure was significantly lower during high-frequency oscillator ventilation than during conventional mechanical ventilation (CMV: 45, 34, 22, 6, 9 mmHg vs. HFOV: 33, 20, 19, 5, 5 mmHg at airway pressures mentioned above, P = 0.02). Intracranial pressure and cerebrovascular resistance increased with increasing intrathoracic pressures (P = 0.001). Cerebral metabolic indices demonstrated an initial increase in anaerobic metabolism followed by a decrease in cerebral oxygen consumption progressing to cerebral infarction as intrathoracic pressures were further increased in a stepwise fashion. Arterial PaCO(2) increased significantly after converting from conventional mechanical ventilation to high-frequency oscillator ventilation (P = 0.001). However, no difference was observed between conventional mechanical ventilation and high-frequency oscillator ventilation when intracranial pressure, metabolic and transcranial Doppler indices were compared at equivalent mean airway pressures.

CONCLUSIONS

The use of high positive end expiratory pressure with conventional mechanical ventilation or high continuous distending pressure with high-frequency oscillator ventilation increased intracranial pressure and adversely affected cerebral metabolic indices in this ovine model. Transcranial Doppler is a useful adjunct to intracranial pressure and intracranial venous saturation monitoring when major changes in ventilation strategy are adopted.

Students with mild disabilities in regular classrooms: the development and utility of the Student Perceptions of Classroom Support scale

BACKGROUND

There is a dearth of empirical research pertaining to the perceptions of students with mild disabilities of the academic and social outcomes of classroom support mechanisms. The absence of suitable measures is a primary issue contributing to this situation.

METHOD

The present study reports the development and utility of the Student Perceptions of Classroom Support (SPCS) scale, which was specifically designed to assess students' perceptions of curricular, instructional, physical, and peer support received in regular classrooms from both an academic and social perspective. The SPCS was administered to 60 secondary school-aged students with mild disabilities who experienced both regular classroom and traditional special education.

RESULTS

Person and item discrimination analyses, and calculation of internal consistencies (Cronbach's alpha) revealed the SPCS to have excellent psychometric properties (alpha = 0.92 for academic outcomes and alpha = 0.87 for overall social outcomes). Internal consistencies for each of the subscales are also reported.

CONCLUSIONS

The SPCS provides educators with a valid method of assessing students' preferred support strategies, which can then be articulated within Individual Education Plans (IEPs).

Autoimmune progesterone dermatitis in a parturient for emergency caesarean section

A parturient with a 14-year history of autoimmune progesterone dermatitis presented in labour at 36 weeks' gestation. She had suffered recurrent episodes of angioedema over a long period and had been scheduled for elective caesarean hysterectomy and bilateral oophorectomy at 37 weeks' gestation. In most cases surgical oophorectomy provides prolonged relief from the recurrent angioedema and dermatological manifestations that are typical of autoimmune progesterone dermatitis. Spinal anaesthesia was chosen in order to avoid airway manipulation, a factor frequently implicated in the development of angioedema. Delivery was uneventful and the obstetricians proceeded to hysterectomy and oophorectomy. Forty minutes after delivery the patient experienced an attack of angioedema, she was markedly hypotensive and was given fluids, ephedrine and phenylephrine with good effect. As she remained normotensive, she was given intramuscular rather than intravenous epinephrine to provide a slower release. She recovered well and stabilised without the need for intubation or ventilation. This case reinforces the rationale for regional anaesthesia in these patients and demonstrates how intramuscular epinephrine contributed towards a positive outcome.

Additional evidence that the sympathetic nervous system regulates the vessel wall release of tissue plasminogen activator

It is established that sympathetic neurons can synthesize, transport and store tissue plasminogen activator (t-PA) within axon terminals in the smooth muscle of vessel walls. Moreover, sympathetic excitations (e.g. physical and mental stress) are known to induce an acute release of t-PA into the circulation. However, relatively little is known about the nature and extent of sympathetic nervous system involvement in the release process. We inquired whether a chemical sympathectomy will alter the release of t-PA into the blood, and the intrinsic release of stored t-PA from isolated whole vessel explants. A long-term sympathectomy was induced in adult Sprague-Dawley rats by injection of guanethidine during a 5-week course. The destruction of ganglion neurons and vessel wall axons was verified immunohistochemically. t-PA release was assayed as the free activity in hind limb plasma and explant culture medium. Following sympathectomy: (i) the basal t-PA activity in plasma was 70% less than controls (2.92 +/- 1.96 versus 9.33 +/- 1.72 IU/ml; </= 0.001); (ii) the acute release from isolated vessels induced by bradykinin or phenylephrine was comparably reduced; and (iii) the greatest reductions occurred in densely innervated small vessel explants. The results provide new support for an autonomic regulation of neural t-PA release into the vessel wall matrix and blood of densely innervated thin-walled microvessels.

C. elegans EGL-9 and mammalian homologs define a family of dioxygenases that regulate HIF by prolyl hydroxylation

HIF is a transcriptional complex that plays a central role in mammalian oxygen homeostasis. Recent studies have defined posttranslational modification by prolyl hydroxylation as a key regulatory event that targets HIF-alpha subunits for proteasomal destruction via the von Hippel-Lindau ubiquitylation complex. Here, we define a conserved HIF-VHL-prolyl hydroxylase pathway in C. elegans, and use a genetic approach to identify EGL-9 as a dioxygenase that regulates HIF by prolyl hydroxylation. In mammalian cells, we show that the HIF-prolyl hydroxylases are represented by a series of isoforms bearing a conserved 2-histidine-1-carboxylate iron coordination motif at the catalytic site. Direct modulation of recombinant enzyme activity by graded hypoxia, iron chelation, and cobaltous ions mirrors the characteristics of HIF induction in vivo, fulfilling requirements for these enzymes being oxygen sensors that regulate HIF.

Blood mononuclear cells induce regulatory NK T thymocytes in anterior chamber-associated immune deviation

Injection of antigen into the anterior chamber (AC) of the eye, an immunologically privileged site, is associated with the induction of immune deviation, as evidenced by T helper cell (Th) 1 to Th2 cell polarization. We recently demonstrated that AC-associated immune deviation (ACAID) is a thymus-dependent phenomenon initiated by the formation of regulatory alpha,beta T-cell receptor-positive CD4(-) CD8(-) thymocytes (THYregs). In this study, the afferent and efferent limbs of this immunoregulatory loop were traced from peripheral blood to the thymus and then to the spleen by adoptive-transfer assays. The results demonstrate that (1) F4/80(+) CD1(+) peripheral blood mononuclear cells from mice whose ACs were injected with trinitrophenol-bovine serum albumin induce the appearance of natural killer (NK) 1.1(+) THYreg in naïve recipients within 24 h of intravenous infusion; (2) these NK THYregs induce (or generate) suppressor-effector T cells in the spleens of adoptive recipients; (3) these suppressor-effector spleen cells, but not the NK THYregs themselves, directly inhibit the expression of delayed-type hypersensitivity in sensitized recipients; and (4) peripheral blood mononuclear cells from AC-injected mice do not induce ACAID in thymectomized recipients. These results confirm our hypothesis that ACAID is a model of centrally induced dominant tolerance mediated by CD-1-dependent NK T cells of recent thymic origin. The results also provide evidence of a novel tolerance induction pathway by which blood-borne antigen-presenting cells generated by antigen injection into an immunologically privileged site transport antigen to the thymus and induce the formation and export of THYreg.

Bacteriology and taxonomy of Helicobacter pylori

As the scientific community approaches the twentieth anniversary of the first isolation of H. pylori, it appears that despite the wealth of articles published in journals throughout the world every month, there are still many unanswered questions about the microbiology of this bacterium and others in the genus Helicobacter.

Restriction fragment length polymorphism analysis of Mycobacterium avium isolates from animal and human sources

Restriction fragment length polymorphism (RFLP) analysis using probes derived from the insertion sequences IS901, IS1245 and IS1311, was carried out on Mycobacterium avium isolates obtained from 18 human patients, 44 deer, 14 pigs and five cattle in the Republic of Ireland. Forty-two of the cervine isolates and two of the bovine isolates contained IS901, while this insertion sequence was absent from all of the human and porcine isolates. RFLP analysis with IS901 probe differentiated the 44 field isolates which contained this element into three types. All of the IS901-positive isolates had a characteristic three-band IS1245 hybridisation pattern and a characteristic single-band IS1311 hybridisation pattern. The IS901-negative isolates exhibited highly polymorphic IS1245 and IS1311 hybridisation patterns which differentiated the human and porcine isolates into a wide diversity of strain types.

Gastric mucosa-associated lymphoid tissue lymphoma: implications of animal models on pathogenic and therapeutic considerations--mouse models of gastric lymphoma

There are a number of Helicobacter species that will readily colonise the mouse stomach for the duration of the animal's life. They are Helicobacter felis, "Helicobacter heilmannii" and Helicobacter pylori. Early studies on long-term infection of BALB/c mice showed the presence of lesions resembling low-grade gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Because of the suggestion that H. pylori was the cause of these tumors in humans, this phenomenon was studied further as it was reasoned that the Helicobacter-infected mice would provide a valuable model of the human disease. Low-grade gastric MALT lymphomas have been shown to follow infection with all the Helicobacter species listed above. These lesions are indistinguishable from the human disease with the presence of centrocyte-like cells, characteristic lymphoepithelial lesions and glandular destruction. Treatment with antimicrobial therapy results in regression of the lymphomas. There is evidence of progression to high-grade in some animals. The Helicobacter mouse models of lymphoma are likely to provide important information relevant not just to H. pylori-induced lesions in the human, but to antigen-driven tumors in general.

Lipopolysaccharide structures of Helicobacter pylori genomic strains 26695 and J99, mouse model H. pylori Sydney strain, H. pylori P466 carrying sialyl Lewis X, and H. pylori UA915 expressing Lewis B classification of H. pylori lipopolysaccharides into glycotype families

This study describes the molecular makeup of the cell-wall lipopolysaccharides (LPSs) (O-chain polysaccharide-->core oligosaccharide-->lipid A) from five Helicobacter pylori strains: H. pylori 26695 and J99, the complete genome sequences of which have been published, the established mouse model Sydney strain (SS1), and the symptomatic strains P466 and UA915. All chemical and serological experiments were performed on the intact LPSs. H. pylori 26695 and SS1 possessed either a low-Mr semi-rough-form LPS carrying mostly a single Ley type-2 blood-group determinant in the O-chain region covalently attached to the core oligosaccharide or a high-Mr smooth-form LPS, as did strain J99, with an elongated partially fucosylated type-2 N-acetyllactosamine (polyLacNAc) O-chain polymer, terminated mainly by a Lex blood-group determinant, connected to the core oligosaccharide. In the midst of semi-rough-form LPS glycoforms, H. pylori 26695 and SS1 also expressed in the O-chain region a difucosylated antigen, alpha-L-Fucp(1-3)-alpha-L-Fucp(1-4)-beta-D-GlcpNAc, and the cancer-cell-related type-1 or type-2 linear B-blood-group antigen, alpha-D-Galp(1-3)-beta-D-Galp(1-3 or 4)-beta-D-GlcpNAc. The LPS of H. pylori strain P466 carried the cancer-associated type-2 sialyl Lex blood-group antigen, and the LPS from strain UA915 expressed a type-1 Leb blood-group unit. These findings should aid investigations that focus on identifying and characterizing genes responsible for LPS biosynthesis in genomic strains 26695 and J99, and in understanding the role of H. pylori LPS in animal model studies. The LPSs from the H. pylori strains studied to date were grouped into specific glycotype families.

Sympathectomy decreases and adrenergic stimulation increases the release of tissue plasminogen activator (t-PA) from blood vessels: functional evidence for a neurologic regulation of plasmin production within vessel walls and other tissue matrices

Our recent morphologic studies indicated that peripheral nervous system (PNS) adrenergic neurons synthesize, transport, and store the serene protease, tissue plasminogen activator (t-PA) in axon terminals, many of which innervate vessel walls. Sympathoadrenal stimulation induces a surge of t-PA from vessel walls into the blood. The vascular endothelium, which constitutively secretes t-PA into blood also has long been widely assumed to be the principal source of this stress-induced release, but has not been verified as such. A neurologically regulated release from adrenergic stores could thus augment the known constitutive endothelial release. To functionally test this possibility, we quantitated the effects of guanethidine-induced systemic sympathectomy on the basal and stimulated release of t-PA from isolated vessel explants in superfused organ cultures. Moment-to-moment changes in the release rate were plotted from serial assays of the t-PA free activity. The effects of endothelial and adventitial nerve plexus ablations were also tested. Sympathectomy induced 30-50% reductions in t-PA release from both arterial and microvascular explants. An acute release induced by alpha-1 adrenergic receptor stimulations was also strongly suppressed, as were basal levels of the circulating enzyme in vivo. Adventitial and endothelial ablations from normal large vessel explants produced greater reductions than small vessel endothelial ablations. Ganglion electrical stimulation also induced an acute microvascular release in vivo. These and past morphologic findings indicate a physiological infusion of t-PA into the vessel walls, blood, and other innervated matrices by sympathetic neurons.

Characterization of Helicobacter felis by pulsed-field gel electrophoresis, plasmid profiling and ribotyping

BACKGROUND

Helicobacter felis, an organism naturally infecting both canine and feline gastric mucosa, has been largely used as in animal models to study the ecology and treatment of human Helicobacter pylori infections. H. felis has not yet been studied at the genetic level.

METHODS

The aims of this study were to modify an in situ DNA isolation method suitable for H. felis and, by the use of pulsed-field gel electrophoresis (PFGE), plasmid profiling, and ribotyping, to determine the degree of genetic variation among H. felis strains isolated from cats and dogs from various geographic locations, and to determine the genome size of H. felis. Furthermore, the ability of these new H. felis strains to colonize mice was tested.

RESULTS

Most H. felis strains were distinguishable from each other, and 20 distinct PFGE types were detected. Four pairs of strains within a country and animal species produced identical patterns. All strains tested were found to carry several plasmids and plasmid profiling was equally discriminatory to PFGE. Ribotyping was not able to discriminate all the strains.

CONCLUSIONS

The genome size of H. felis was found to be approximately 1.6 Mb.

Functional and morphologic evidence of the presence of tissue-plasminogen activator in vascular nerves: implications for a neurologic control of vessel wall fibrinolysis and rigidity

Tissue plasminogen activator (t-PA) is expressed by hypothalamic and peripheral sympathetic neurons. The sympathetic axons that permeate artery walls have not been investigated as possible sources of intramural t-PA. The plasmin produced by such a system would locally activate both fibrinolysis and matrix metalloproteinases that regulate arterial collagen turnover. To assess this neural t-PA production, we investigated the capacity of rat cervical sympathetic ganglion neurons to synthesize and release t-PA, and the expression of the enzyme in carotid artery and the iris-choroid microvascular tissues that receive the ganglion axon distribution. Functional studies confirmed that (i) the ganglion neuron cell bodies synthesize t-PA mRNA, (ii) cultured ganglion carotid artery and iris-choroid microvascular explants predominantly release t-PA rather than urokinase, (iii) microvascular tissues release approximately 20 times more t-PA per milligram than carotid explants (which accords with the higher innervation density of small vessels), and (iv) removal of the endothelium did not cause major reductions in the t-PA release from carotid and microvascular explants. Immunolocalization studies then confirmed a strong expression of the enzyme within the ganglion axons, the carotid adventitia that receives these axons, and the predominantly sympathetic axon terminals in the iris-choroid microvasculature. These data indicate the existence of a previously undescribed system for the delivery of neural t-PA to vessel walls. The intramural production of plasmin induced by this system represents a novel principle for the regulation of arterial matrix flexibility, especially in the media of densely innervated small arteries and resistance arterioles involved in the pathogenesis of stroke, hypertension, and vascular aging. Thus, the data suggest an important new interface between neuroscience and vascular biology that merits further exploration.

Antigen-dependent progression of mucosa-associated lymphoid tissue (MALT)-type lymphoma in the stomach. Effects of antimicrobial therapy on gastric MALT lymphoma in mice

In humans, low-grade B-cell mucosa-associated lymphoid tissue (MALT) lymphomas of the stomach regress when Helicobacter pylori infection is cured by antimicrobial therapy. Using an animal model of human gastric MALT lymphoma, we observed the effects of Helicobacter felis eradication and the relationship between infection and disease progression. Antimicrobial therapy was given to one-half of the BALB/c mice infected with H. felis for 20 months. Groups of antibiotic-treated and untreated mice were killed 2, 3, and 4 months after antimicrobial therapy (ie, 22, 23, and 24 months after infection). The numbers of mice with MALT decreased after H. felis eradication with no lymphoid follicles seen 4 months after treatment. MALT lymphoma was present in a total of 23% (11/48) of antibiotic-treated infected mice compared with 75% (27/36) in untreated infected mice. These lymphomas were further graded into low-, intermediate-, and high-grade lymphoma. In the untreated mice, lymphoma development was more advanced with 36% low-grade (13/36), 39% intermediate-grade (14/36), and 6% high-grade (large B-cell) lymphoma (2/36) whereas in the treated mice the incidence was 21% (10/48), 6% (3/48), and 0% (0/48), respectively. These observations suggest that antigenic stimulation by H. felis sustained growth and progression of low-grade MALT lymphoma and that primary high-grade gastric lymphomas can evolve from the transformation of these tumors. Eradication of the organism caused low-grade tumors to regress, with inhibition or slowing down of lymphoma development toward high-grade lymphoma. The H. felis mouse model of gastric MALT lymphoma presents an opportunity to address the issues arising from antimicrobial treatment of these tumors in humans.

Effect of transforming growth factor-beta1 on parathyroid hormone-related protein secretion and mRNA expression by normal human keratinocytes in vitro

Parathyroid hormone-related protein (PTHrP) is produced by a wide range of neoplastic and normal cells, including keratinocytes where it may regulate growth and differentiation. Transforming growth factor-beta (TGF-beta) is a growth factor produced by many cells, including keratinocytes where it regulates epidermal homeostasis. TGF-beta has been reported to be cosecreted with PTHrP in some neoplasms and to stimulate PTHrP production by neoplastic keratinocytes. However, the effects of TGF-beta on PTHrP production by normal keratinocytes are not well characterized. In this study, we investigated the effects of endogenous and exogenous TGF-beta on PTHrP production by normal human foreskin keratinocytes. PTHrP secretion, mRNA expression, and mRNA transcription in vitro were determined by N-terminal radioimmunoassay, ribonuclease protection assay, and transient transfections. PTHrP production and secretion of latent TGF-beta activity were greatest in proliferating keratinocytes prior to and at confluence of monolayer cultures. TGF-beta1 increased PTHrP mRNA expression by normal keratinocytes in a dose-dependent manner with maximal stimulation at 6-1 2 h after treatment. In addition, keratinocytes treated with a monoclonal anti-TGF-beta antibody expressed decreased levels of PTHrP mRNA. The increased levels of PTHrP mRNA following TGF-beta1 treatment were owing, at least partly, to an increase in PTHrP mRNA stability. TGF-beta1 failed to activate transcription of the luciferase reporter gene driven by either the human or mouse PTHrP promoters. In conclusion, TGF-beta1 functions as a paracrine or autocrine regulator of PTHrP production in normal human keratinocytes, and this may play a role in the regulation of keratinocyte proliferation or differentiation.

Extracellular (soluble) antigen-specific T cell proteins related to the T cell receptor for antigen (sTCRr): serologic and primary amino acid sequence similarity to T cell receptor alpha chains and association with cytokines

Antigen-specific-effected immunoregulation by T lymphocytes is mediated by extracellular proteins produced by T lymphocytes. These immunoproteins bind specifically to nonprocessed antigen and either induce antigen-specific immunoregulatory T cells (tsfi) or effect regulation (tsfe). T cell proteins that bind specifically to nonprocessed antigen have ben termed "T cell antigen-binding molecules" (TABM), and by definition, tsfe and tsfi are, in part, TABM. To characterize tsfi, tsfe, and TABM and understand the relationships and function of these immunoproteins, we have combined the efforts of two laboratories to compare tsfi, tsfe, and TABM isolated by each laboratory. Data obtained in one laboratory were reproduced by the other, and all reagents prepared by each laboratory were exchanged. TABM, tsfi, and tsfe were found to express TCRCalpha epitopes but not TCRCbeta epitopes. The amino acid sequence of a tryptic peptide of a T cell hybridoma TABM specific for nitrophenylhydroxy acetate (NP) is similar to a TCRalpha chain and TCR pre-alpha chain amino acid sequence. ELISA and immunoblotting demonstrated that Mr 77,000 T cell hybrid-derived tsfi, tsfe, and TABM are noncovalently associated with Mr 15,000-16,000 interleukin-10 (IL-10). ELISA also demonstrated that tsfi and tsfe are associated with I-J. The ability of tsfi and tsfe to suppress a mixed lymphocyte reaction was prevented by anti-IL-10 or anti-I-J antibodies, suggesting that antigen-specific immunoregulatory T cell proteins function by an antigen-specific focusing of immunoregulatory cytokines.