A scoping review on e-cigarette environmental impacts

INTRODUCTION

The use of e-cigarettes has grown in popularity worldwide. From their manufacturing, use, and disposal, the environmental impacts of e-cigarettes present a novel public health concern that needs to be urgently investigated. However, very limited studies have focused on the subject matter. The present study aims to review available studies to identify the environmental impacts of e-cigarettes.

METHODS

In this scoping review, we undertook a search in two databases (PubMed and Web of Science) from inception until 21 March 2023, and a gray literature search in Google Scholar. Reference lists of publications included in the scoping review were screened manually for additional relevant publications. Scientific publications that were in English and focused on the potential impacts of e-cigarettes on the environment were included.

RESULTS

A total of 693 publications were identified, of which 33 were subjected to full-text review and 9 publications were finally included in the review. The impacts on air quality, water, land use, and animals, water and energy consumption, with associated environmental impacts, increased pollution and emissions due to greater e-cigarette production, having harmful and toxic components, creating pollution and waste issues, and global environmental impacts due to manufacturing and importing ingredients and components from low- and middle-income countries, were identified as the environmental impacts of e-cigarettes.

CONCLUSIONS

Despite the emphasis on the environmental threat of e-cigarettes, there are limited scientific studies on the environmental impacts of the e-cigarette life cycle. Considering the rapid expansion of e-cigarette usage, there is an urgent need for a rigorous assessment of their life-cycle environmental burden of the various potential health, environmental, and other consequences.

Long life: Aging and the anxieties of longevity from the premodern to the present

The COVID-19 pandemic has exposed concerns around life span and aging, but these tensions and anxieties around longevity are not new. Physicians, scientists, and philosophers have been meditating on the idea and consequences of life extension for many centuries. In this short article, we put into conversation some of the ways that people have understood longevity from the early modern period to the present. We trace the history of texts like Alvise Cornaro's Treatise on the Sober Life through present-day dieting manuals, consider accounts of extreme old age from Old Man Parr in the sixteenth century to Jeanne Calment in the twentieth, and reflect on the role of caretakers for older adults, from Gabriele Zerbi's fifteenth-century gerontocomos to graphic novel representations of aging parents in the present. Our goal is to represent the history of human longevity and aging as integrated, dynamic processes, helping us better explain and address the present treatment of elders and how to improve their care in the future.

Engaging the health sector in climate-resilient WASH development

The impact of climate change on water, sanitation, and hygiene (WASH) has driven an increased focus on climate-resilient WASH development. Evidence suggests that adaptation in the WASH sector is underway, but the progress is limited in certain domains and the participation of the public health community may be lacking. Using the Lake Victoria Basin (LVB) as a climate vulnerability setting for this analysis, this study aimed to identify factors that impede full engagement of the health sector in climate-resilient WASH development. In-depth semi-structured interviews were conducted with 13 WASH sector stakeholders across lakeside urban centers in Kenya, Uganda, and Tanzania. Several barriers to health sector engagement were identified including factors related to donor-driven financing and priority setting, a relative neglect of climate vulnerabilities associated with sanitation and hygiene, ministerial siloes, and broader systems of adaptation governance which compromise health sector leadership in climate adaptation. These results suggest room for expansion of interdisciplinary collaborations and deepened involvement of the health sector in WASH-related climate adaptation, which starts with addressing these and other barriers to full health sector engagement.

Shattering crystal with crystal: Galileo's rhetoric, lenses, and the epistemology of metaphor

The terms that Galileo's contemporaries used for lenses (cristallo/i, lente/i, and vetro/i) have often been treated, and even translated, interchangeably. In this article, we argue that Galileo used references to crystals as lenses to embed epistemological and cosmological arguments in the material object of the telescope. Across Galileo's correspondence and letters, the term crystal had many uses and meanings. As a substance, crystal was a form of raw material, but crystal was also a substance that was central to scholastic cosmology and an explanatory device on which scholastics relied to explain first the appearance of the new star of 1604 and then Galileo's new telescopic discoveries. When Galileo began using the word crystals as a synonym for lenses, he endowed the material of his instrument with cosmological arguments. Galileo's choice of language was deliberate and polemical, serving as a joke at the expense of scholastics and as a linguistic marker of social proximity to Galileo and his intellectual agenda, especially among the members of the Academy of the Lincei. Rhetorically and linguistically, Galileo chose to refer to his lenses as crystals both because of the material from which they were made and because in so doing he signaled the epistemological work that the lenses would perform. Ultimately, the crystal lenses in Galileo's telescope and writings shattered the crystalline spheres, replacing explanatory metaphors with a polemical emphasis on the material and empirical realities of objects.

Climate Change and the Public Health Imperative for Supporting Migration as Adaptation

In an era of accelerating global climate change, human mobility has reached unprecedented levels. While it is acknowledged that many cases of human migration in the context of climate change are forced or involuntary, particularly where adaptation measures have failed to achieve sufficient resiliency of communities against impending slow- and sudden-onset disasters. There are also many cases where migration is, itself, a voluntary adaptive measure to secure otherwise unattainable physical safety and life-sustaining resources. It is in these cases that migration can be viewed as adaptation. Under the right policy conditions, it is possible for such adaptive migration to save countless lives. Moreover, it can achieve remarkable health and well-being gains for otherwise vulnerable communities residing on environmentally degrading lands and disproportionately suffering from the health impacts of climate change. While several activists have spoken loudly on the topic of climate migration, emphasizing the human rights imperative for supportive global policy action, the public health community has not been equally vocal nor unanimous in its stance. This paper, a product of the World Federation of Public Health Associations (WFPHA) Environmental Health Working Group, aims to rectify this gap, by analyzing adaptive climate migration through a public health lens. In doing so, it argues that creating an enabling environment for adaptive climate migration is not just a human rights imperative, but also a public health one. This argument is supported by evidence demonstrating how creating such an enabling environment can synergistically support the fulfillment of key public health services and functions, as outlined under the internationally endorsed Global Charter for the Public's Health of the WFPHA.

Knowing Old Age in the Renaissance: Medicine, Poetry, and Spirituality in Ulisse Aldrovandi's Encyclopedia of Old Age

Over more than thirty years the Bolognese botanist, natural historian, and physician Ulisse Aldrovandi compiled his Pandechion epistemonicon-a manuscript encyclopedia composed of pasted note slips drawn from books he was reading. This article examines the 580 slips that comprise Aldrovandi's Pandechion entry on old age. The entry allows us to examine how an early modern physician and his intellectual community approached old age as an epistemological problem with medical, poetic, and spiritual dimensions. Aldrovandi's engagement with old age in the Pandechion presents a fluid set of disciplinary boundaries for how we understand old age in the past and present.

Legal implications of the climate-health crisis: A case study analysis of the role of public health in climate litigation

Background

Strong scientific evidence affirms that climate change is now a public health emergency. Increasingly, climate litigation brought against governments and corporations utilizes international human rights, environmental and climate laws and policies to seek accountability for climate-destructive and health-harming actions. The health impacts of climate change make litigation an important means of pursuing justice and strategically challenging legal systems. Yet there is scant documentation in the literature of the role that public health has played in climate litigation and the legal weight public health narratives are given in such contexts. Therefore, we assessed to what extent courts of law have used public health harm in legal adjudication and sought to provide practical recommendations to address barriers to positioning legal arguments in public health-centric frames.

Methods

We reviewed legal databases to identify all publicly reported, documented, cases of climate litigation filed in any country or jurisdiction between 1990 and September 2020. For the 1641 cases identified, we quantified the frequency of cases where health concerns were explicitly or implicitly raised.

Findings

Case numbers are trending upwards, notably in high income countries. Resolution remains pending in over half of cases as the majority were initiated in the past three years. Cases were primarily based in climate and human rights law and brought by a wide range of groups and individuals predominantly against governments. About half of the decided cases found in favour for the plaintiffs. Based on this, we selected the 65 cases that were directly linked to public health. We found economic forces and pricing of health risks play a key role, as courts are challenged by litigants to adjudicate on the responsibility for health impacts.

Conclusions

While courts of law are receptive to public health science, significant legal reform is needed to enhance leveraging of public health evidence in legal judgements of climate litigation cases. The integration of a public health mandate into a new eco-centric legal paradigm will optimize its potential to promote human well-being—the core objective underpinning both international law, human rights, and public health. Existing legal doctrines and practices can be enhanced to increase the weight of public health arguments in climate legal action and consequently ensure legal rulings in climate litigation prioritize, protect and promote public health.

662 Tool-tissue Forces in Surgery: A Systematic Review

Introduction

Excessive tool-tissue interaction forces in surgery may result in tissue damage and intraoperative complications, while insufficient forces prevent the completion of the task.

Method

A systematic review of studies exploring tool-tissue forces applied during surgery was performed in accordance with PRISMA guidelines.

Results

45 studies discussing tool-tissue forces during surgical procedures or tasks were included. Mean forces per speciality were as follows: ophthalmology (0.04N), vascular (0.7N), neurosurgery (0.68N), cardiothoracic surgery (1.5N), general surgery (4.7N), otorhinolaryngology (8.5N), obstetrics & gynaecology (mean 8.7N), urology (9.8N) and orthopaedic surgery (210N). Senior surgeons applied 25% less force than novice surgeons, and feedback (haptic, visual or audio) reduced force application by 40% - across specialities and tasks. Nervous tissue required the least amount of force to manipulate (0.4N, n = 17), followed by epithelial (3.8N, n = 18), muscle (4.1N, n = 4) and connective tissue (45.8, n = 10). For manoeuvres, retraction-with-grasping recorded the highest forces (3.65N, n = 13), whilst vessel clamping recorded the lowest (0.5N, n = 2).

Conclusions

The measurement of tool-tissue forces is a novel but rapidly expanding field. Knowledge of the safe range of surgical forces will improve surgical safety whilst maintaining effectiveness. Measuring surgical forces may provide an objective metric for training and assessment. Development of smart instruments, robotics and integrated feedback systems will facilitate this.

Effect of Anemia on Work Productivity in Both Labor- and Nonlabor-Intensive Occupations: A Systematic Narrative Synthesis

BACKGROUND

Anemia is highly prevalent particularly in low- and middle-income countries. Iron deficiency contributes to an estimated 50% of anemia cases. Iron interventions have become central to global anemia treatment and prevention; however, few iron interventions have been scaled up to the national level, despite their proven effectiveness. While both cross-sectional and interventional studies on the effect of anemia and iron supplementation on worker productivity have been conducted, there have been few systematic reviews conducted. As such, a synthesis of previously conducted primary research is warranted and may provide a more comprehensive overview of the strength of currently available evidence, potentially helping to inform national policy on matters relating to funding and legislation for population-level iron interventions.

OBJECTIVES

The objective of this study was to synthesize available evidence on the effect of both anemia and therapeutic iron interventions on productivity in working adults.

METHODS

All relevant English language studies were systematically obtained from both MEDLINE and EMBASE and assessed for evidence of differing productivity levels across groups stratified by iron intervention or anemia status. Potential mediating variables were reported, and the results were narratively summarized.

RESULTS

The available data from 12 included studies provide strong evidence that anemia negatively impacts occupational performance and that therapeutic iron interventions can yield substantial productivity gains.

CONCLUSIONS

Despite their limitations, these findings make an important contribution to the literature highlighting the impact of iron deficiency and population-wide iron interventions on work productivity and occupational performance.

Understanding national barriers to climate change adaptation for public health - a global survey

Background

Climate change has introduced a series of unprecedented threats to human health, ranging from rising food and water insecurity to deteriorating air quality, novel disease outbreaks, and intensifying natural disasters. The Paris Agreement pushes countries to develop adaptation plans that will protect human health from the worst impacts of climate change -a process referred to as climate change adaptation (CCA). Yet despite international pressure and escalating health threats, vast shortcomings persist in national CCA for public health progress. Thus, we investigated the major governance constraints underlying these trends.

Methods

A mixed-methods online survey was distributed to representatives of national public health associations and societies of 82 member countries under the World Federation of Public Health Associations.

Results

9 of the 11 respondent countries (82%) affirmed the existence of a national CCA plan that includes an explicit public health focus. All respondees listed governance challenges in developing and operationalising their national CCA agenda. The major identified barriers to CCA for public health progress were lack of inter-government policy coordination and insufficient political will to mobilize human and non-human resources in support of public health-oriented adaptation efforts.

Conclusions

Climate change-driven amplification of global health risks necessitates that all nations generate clear CCA plans to protect human health. Our findings assist by highlighting the need for new platforms for organizational collaboration/networked governance and enhanced forums for CCA agenda-setting and ambition-raising. Such forms of enriched knowledge may facilitate decision-making amongst key public health stakeholders and global institutions for how best to align climate advocacy and country-wide support initiatives with cross-cutting national needs and constraints.

Key messages

Climate change-driven amplification of global health risks necessitates that all nations generate clear climate change adaptation plans to protect human health. New platforms for organizational collaboration/networked governance and enhanced forums for adaptation agenda-setting and ambition-raising may significantly bolster public health adaptation progress.

The breakdown of Galileo's Roman network: Crisis and community, ca. 1633

Rome has long been central to the story of Galileo's life and scientific work. Through an analysis of the metadata of Galileo's surviving letters, combined with a close reading of the letters themselves, we discuss how Galileo used correspondence to build a Roman network. Galileo initially assembled this network around the members of the Lincean Academy, a few carefully nurtured relationships with important ecclesiastics, and the expertise of well positioned Tuscan diplomats in the Eternal City. However, an analysis of Galileo's correspondence in the aftermath of the trial of 1633 provides us with a unique opportunity to interrogate how his altered circumstances transformed his social relations. Forced to confront the limitations on his activities imposed by Catholic censure and house arrest, Galileo experienced the effects of these restrictions in his relationships with others and especially in his plans for publication. In the years following 1633, Galileo turned his epistolary attention north to the Veneto and to Paris in order to publish his Two New Sciences. While Galileo's Lincean network and papal contacts in Rome were defunct after 1633, we see how Rome remained important to him as the site of a number of Roman disciples who would continue his intellectual project long after his own death.

The Mealtime Audit Tool (MAT) - Inter-Rater Reliability Testing of a Novel Tool for the Monitoring and Assessment of Food Intake Barriers in Acute Care Hospital Patients

OBJECTIVES

Barriers to food intake (FI) exist in hospital that could exacerbate insufficient FI and malnutrition. The Mealtime Audit Tool (MAT) is a staff-administered clinical assessment tool to identify FI barriers for individual patients. Two studies were completed. The objectives of the first study were to test a draft version of the tool and characterize barriers to food intake in older adults in four diverse hospitals, while the second study aimed to demonstrate the inter-rater reliability of the revised MAT.

DESIGN

Multi-site, cross sectional.

SETTING

Four acute care hospitals in Canada.

PARTICIPANTS

Study 1: 120 older (65+ years, adequate cognition) medical or surgical patients. Study 2: 90 medical or surgical patients.

MEASUREMENTS

In study 1, participants had barriers experienced at one mealtime assessed with MAT. Descriptive analyses characterized the prevalence of barriers across the hospitals. Revisions were made to the MAT based on recommendations from sites. A revised version was tested for inter-rater reliability in study 2. Intraclass correlation coefficient (ICC) was calculated for total MAT scores from 90 patient meals assessed by two raters. Kappa statistics were calculated for each of the 18 MAT items.

RESULTS

Mean (+/- standard deviation) number of barriers experienced in Study 1 was 2.93 +/- 1.58, and in Study 2 was 2.51 +/- 1.19. The revised MAT was reliable with an ICC of 0.68 (95%CI: 0.52-0.79). Ten of 16 items in which kappa could be calculated had at least fair agreement.

CONCLUSION

MAT is sufficiently reliable when used by auditors with minimal training. Routinely auditing mealtimes with MAT could be useful in identifying and removing barriers to food intake for older hospitalized patients.

Quality Nutrition Care: Measuring Hospital Staff's Knowledge, Attitudes, and Practices

Understanding the knowledge, attitudes, and practices (KAP) of hospital staff is needed to improve care activities that support the detection/prevention/treatment of malnutrition, yet quality measures are lacking. The purpose was to develop (study 1) and assess the administration and discriminative potential (study 2) of using such a KAP measure in acute care. In study 1, a 27-question KAP questionnaire was developed, face validated (n = 5), and tested for reliability (n = 35). Kappa and Intraclass Correlation (ICC) were determined. In study 2, the questionnaire was sent to staff at five diverse hospitals (n = 189). Administration challenges were noted and analyses completed to determine differences across sites, professions, and years of practice. Study 1 results demonstrate that the knowledge/attitude (KA) and the practice (P) subscales are reliable (KA: ICC = 0.69 95% CI 0.45-0.84, F = 5.54, p < 0.0001; P: ICC = 0.84 95% CI 0.68-0.92, F = 11.12, p < 0.0001). Completion rate of individual questions in study 2 was high and suggestions to improve administration were identified. The KAP mean score was 93.6/128 (range 51-124) with higher scores indicating more knowledge, better attitudes and positive practices. Profession and years of practice were associated with KAP scores. The KAP questionnaire is a valid and reliable measure that can be used in needs assessments to inform improvements to nutrition care in hospital.

Mesenchymal stem cells secretomes' affect multiple myeloma translation initiation

Bone marrow mesenchymal stem cells' (BM-MSCs) role in multiple myeloma (MM) pathogenesis is recognized. Recently, we have published that co-culture of MM cell lines with BM-MSCs results in mutual modulation of phenotype and proteome (via translation initiation (TI) factors eIF4E/eIF4GI) and that there are differences between normal donor BM-MSCs (ND-MSCs) and MM BM-MSCs (MM-MSCs) in this crosstalk. Here, we aimed to assess the involvement of soluble BM-MSCs' (ND, MM) components, more easily targeted, in manipulation of MM cell lines phenotype and TI with specific focus on microvesicles (MVs) capable of transferring critical biological material. We applied ND and MM-MSCs 72h secretomes to MM cell lines (U266 and ARP-1) for 12-72h and then assayed the cells' (viability, cell count, cell death, proliferation, cell cycle, autophagy) and TI (factors: eIF4E, teIF4GI; regulators: mTOR, MNK1/2, 4EBP; targets: cyclin D1, NFκB, SMAD5, cMyc, HIF1α). Furthermore, we dissected the secretome into >100kDa and <100kDa fractions and repeated the experiments. Finally, MVs were isolated from the ND and MM-MSCs secretomes and applied to MM cell lines. Phenotype and TI were assessed. Secretomes of BM-MSCs (ND, MM) significantly stimulated MM cell lines' TI, autophagy and proliferation. The dissected secretome yielded different effects on MM cell lines phenotype and TI according to fraction (>100kDa- repressed; <100kDa- stimulated) but with no association to source (ND, MM). Finally, in analyses of MVs extracted from BM-MSCs (ND, MM) we witnessed differences in accordance with source: ND-MSCs MVs inhibited proliferation, autophagy and TI whereas MM-MSCs MVs stimulated them. These observations highlight the very complex communication between MM and BM-MSCs and underscore its significance to major processes in the malignant cells. Studies into the influential MVs cargo are underway and expected to uncover targetable signals in the regulation of the TI/proliferation/autophagy cascade.

Using fMRI to evaluate the effects of milnacipran on central pain processing in patients with fibromyalgia

Background

In recent years, the prescription of serotonin-noradrenalin reuptake inhibitors (SNRIs) for treatment of fibromyalgia (FM) has increased with reports of their efficacy. The SNRI milnacipran is approved by the U.S. Food and Drug Administration (FDA) for treatment of FM, yet, the mechanisms by which milnacipran reduces FM symptoms are unknown. A large number of neuroimaging studies have demonstrated altered brain function in patients with FM but the effect of milnacipran on central pain processing has not been investigated. The primary objective of this study was to assess the effect of milnacipran on sensitivity to pressure-evoked pain in FM. Secondary objectives were to assess the effect of milnacipran on cerebral processing of pressure-evoked pain using fMRI and the tolerability and safety of milnacipran 200 mg/day in FM.

Methods

92 patients were randomized to either 13-weeks milnacipran treatment (200 mg/day) or placebo in this double-blind, placebo-controlled multicenter clinical trial. Psychophysical measures and functional MRI (fMRI) assessments were performed before and after treatment using a computer-controlled pressure-pain stimulator. Here, we present the results of several a priori defined statistical analyses.

Results

Milnacipran-treated patients displayed a trend toward lower pressure-pain sensitivity after treatment, compared to placebo, and the difference was greater at higher pain intensities. A single group fMRI analysis of milnacipran-treated patients indicated increased pain-evoked brain activity in the caudatus nucleus, anterior insula and amygdala after treatment, compared to before treatment; regions implicated in pain inhibitory processes. A 2 × 2 repeated measures fMRI analysis, comparing milnacipran and placebo, before and after treatment, showed that milnacipran-treated patients had greater pain-evoked activity in the precuneus/posterior cingulate cortex after treatment; a region previously implicated in intrinsic brain function and FM pathology. This finding was only significant when uncorrected for multiple comparisons. The safety analysis revealed that patients from both treatment groups had treatment-emergent adverse events where nausea was the most common complaint, reported by 43.5% of placebo patients and 71.7% of milnacipran-treated patients. Patients on milnacipran were more likely to discontinue treatment because of side effects.

Conclusions

Our results provide preliminary indications of increased pain inhibitory responses in milnacipran-treated FM patients, compared to placebo. The psychophysical assessments did not reach statistical significance but reveal a trend toward higher pressure-pain tolerance after treatment with milnacipran, compared to placebo, especially for higher pain intensities. Our fMRI analyses point toward increased activation of the precuneus/posterior cingulum in patients treated with milnacipran, however results were not corrected for multiple comparisons. The precuneus/posterior cingulum is a key region of the default mode network and has previously been associated with abnormal function in FM. Future studies may further explore activity within the default mode network as a potential biomarker for abnormal central pain processing.

Implications

The present study provides novel insights for future studies where functional neuroimaging may be used to elucidate the central mechanisms of common pharmacological treatments for chronic pain. Furthermore, our results point toward a potential mechanism for pain normalization in response to milnacipran, involving regions of the default mode network although this finding needs to be replicated in future studies.

Lipid therapy for serotonin syndrome after intoxication with venlafaxine, lamotrigine and diazepam

A 44-year-old woman developed coma and seizure activity after intentional ingestion of 200 mg diazepam, 20 g lamotrigine and 4.5 g venlafaxine. In our intensive care unit a distinct rigidity and hyperreflexia was observed. This status was not influenced by haemodialysis which was initiated directly after admission. Plasma concentrations of the ingested drugs were determined before hemodialysis was started (560 µg/L diazepam, 42.4 mg/L lamotrigine and 1254 µg/L venlafaxine). Eight hours after the start of haemodialysis a 150 mL (2.5 mL/kg) intravenous bolus of 20% lipid emulsion was given. Soon after administration of the lipid infusion the distinct rigidity and hyperreflexia disappeared. The further course was uneventful.

[Measuring pressure pain thresholds. Comparison of an electromechanically controlled algometer with established methods]

BACKGROUND

Measurement of the pressure pain threshold and suprathreshold pressure pain sensitivity using a newly developed computer controlled algometer was compared to established methods in this pilot study.

METHODS

The pressure pain threshold was measured in 64 chronic pain patients and 37 healthy volunteers with a manual electronic algometer (Somedic) and the computer controlled Algoforce PA3. Stimulus-response curves with painful stimuli were applied using the Algoforce PA3 and a hydraulic algometer.

RESULTS

Overall means and variance of the pressure pain thresholds for both methods were similar. For low pain thresholds the Algoforce PA3 generally resulted in lower values and for high pain thresholds in higher values. No differences were seen for suprathreshold pain sensitivity. Gender and the presence of chronic pain had no relevant effect on the different methods in both comparisons.

CONCLUSION

For clinical use, the algometers investigated deliver comparable results. For studies requiring high precision with low levels of stimulation the use of the Algoforce PA3 could be considered.

Application of recovery tests in the validation of immunoassays for assessing the immunogenicity of B. anthracis PA vaccine

In the quantitative assessment of polyclonal serum antibodies, the complex composition and characteristics of the analyte population (serum antibodies) restricts the capability of constructing appropriately defined calibration standards. This fact limits the application of the conservative recovery tests to the validation of immunoassays aimed at determining serum antibody levels. The present report describes a modification of recovery tests that overcomes this impediment. The modified approach is based on a dilution analysis system, where a given immune serum is serially diluted in normal serum and the antibody titers in each of the derived diluted samples are then determined. Expected sample titers (calculated on the basis of the relevant dilution factors) are plotted against the respective observed results, and the resulting recovery curve is then examined by means of a regression analysis, according to the standard rules of the conservative recovery analysis. This approach was tried with two immunoassay systems, Enzyme Linked Immunosorbent Assay (ELISA) and Neutralizing Antibodies (NtAb) immunoassays, aimed at assessing the immunogenicity in guinea pigs of B. anthracis protective antigen (PA) vaccine. In a series of feasibility studies using a recovery simulation model (dilutions made in the immunoassay diluent, rather than in normal serum) the average recovery levels in ELISA and NtAb immunoassays were 0.99 +/- 0.011 and 1.02 +/- 0.04 respectively, and the 99% confidence intervals contained the target 100% value. Regression lines were proved to be linear demonstrating R > 0.97 in all cases. The 99% confidence intervals around the observed slopes and intercepts always contained the corresponding target values 1 and 0. The relative standard deviation (RSD) in the ELISA and NtAb immunoassays was found to be 0.01 and 0.025 respectively. All of the above experimental results were not affected by the serum antibody titer, or by day-to-day variations embodied in these immunoassay systems. When true recovery tests were applied to the above immunoassays, essentially identical results were obtained. In both assays the correlation coefficients were in the range of 0.96-1, recoveries were found to be in the range of 0.90-1.06, and RSD values were in the range of 0.02-0.025. All the recovery deviations from the target value of 1 were not statistically significant. The hitherto observed experimental findings illustrate the capability of the dilution analysis system to allow the application of recovery tests to the validation of quantitative immunoassays, which are based on the procedure of serum titrations.

In vivo modulation of the allogeneic immune response by human fetal kidneys: the role of cytokines, chemokines, and cytolytic effector molecules

BACKGROUND

We have recently demonstrated that human fetal renal tissue, implanted under the kidney capsule of severe immunodeficient rats, escapes early destruction by intraperitoneal infusion of allogeneic human peripheral blood mononuclear cells, compared with the rapid rejection of implants of human adult kidney tissue. Variable amounts of human mononuclear infiltrates were seen in the transplanted fetal kidney, however, prolonged survival of the fetal tissue (maintenance of graft architecture and significant growth) was independent of the cellular infiltrate.

METHODS

We have used this experimental model to sequentially analyze transcript levels of interferon-gamma and interleukin (IL)-2 (T helper 1 cytokines), IL-4 and IL-10 (T helper 2 cytokines), RANTES, MIP1beta (beta chemokines) and their receptor CCR5, and Fas ligand (cytolytic effector molecule). Analysis was performed by reverse transcriptase-polymerase chain reaction, in both fetal and adult kidney grafts, after infusion of allogeneic human peripheral blood mononuclear cells.

RESULTS

Transcript levels of interferon-gamma and IL-2 in the fetal grafts were markedly reduced throughout follow-up, compared with those observed in the adult implants. Peak levels of these cytokines appeared late in the rejection process. Concomitant with these findings, IL-4 mRNA was up-regulated during the early phase, whereas IL-10 mRNA persisted throughout the rejection process, indicating that a T helper 2 bias occurred in the fetal grafts. In addition, RANTES (after an early peak), MIP1beta, CCR5, and Fas ligand mRNA levels were suppressed in the fetal grafts compared with those in the adult grafts.

CONCLUSIONS

These findings indicate that the immune response of kidney rejection is dependent on whether the target organ is of fetal or adult origin, and suggest that an allogeneic immune system mounts a T helper 2-biased response when the target organ is of fetal origin.

Reduced hepatitis B virus surface antigen-specific Th1 helper cell frequency of chronic HBV carriers is associated with a failure to produce antigen-specific antibodies in the trimera mouse

In chronic hepatitis B virus (HBV) infection weak antiviral immune responses are associated with viral persistence. We studied possible immune deficits underlying the lack of serum antibodies of such patients against the HBV surface antigen (HBsAg) in a novel human/mouse chimeric model. A hepatitis B surface antigen (HBs) vaccination of Balb/c mice engrafted with peripheral blood mononuclear cells (PBMC) of naturally HBV-immunized donors induced high frequencies of human HBsAg-specific B and T helper 1 (Th1) cells. These responses were associated with high serum anti-HBs antibody levels of the subclasses immunoglobulin G1 (IgG1) and IgG2 that are driven by interleukin-2 (IL-2) and interferon-gamma (IFN-gamma). In contrast, PBMC of chronic HBV carriers transplanted into the chimera failed to produce anti-HBs antibodies after vaccination with HBsAg and exhibited a deficit of antigen-specific Th1 cells. A possible influence of HBsAg or viremia was excluded by the lack of viral replication in such chimera. The observed T-cell defect was specific for HBsAg, as the B- and T-cell responses to tetanus toxoid (TT) were fully retained. Thus, our study shows that viral persistence in chronic HBV carriers is associated with an HBsAg-specific Th1 cell defect, which likely is responsible for the insufficient neutralizing anti-HBs-antibody response and is not reversed by HBs vaccination. Alternative approaches to induce HBs-specific Th1 cell responses might represent a future therapeutic option.

The effect of cisapride on total parenteral nutrition-associated cholestasis in rats

BACKGROUND

Cholestasis is a frequent problem in patients on total parenteral nutrition. Cisapride has a prokinetic effect on the biliary system, but its effect on hepatic excretory function is unknown.

OBJECTIVES

To study the effect of cisapride on TPN-induced cholestasis in a rat model.

METHODS

Bile flow and bile salt secretion rate were measured in rats given TPN. There were four groups of 8 to 13 animals each. After a one hour baseline period during which all four groups received i.v. saline infusion, two groups received a TPN solution for another 2 hours, while saline was infused in the two control groups. At the beginning of the second hour, 2 mg/kg cisapride was injected i.v. as a bolus into one experimental and one control group. Bile was collected from the common bile duct.

RESULTS

At the end of the third hour, TPN caused a significant reduction in bile flow (P < 0.02) and bile salt secretion rate (P < 0.001) (61.24 vs. 50.74 microliters/min/kg, and 1.173 vs. 0.799 mumol/min/kg, respectively). Addition of cisapride abolished the cholestatic effect of TPN.

CONCLUSIONS

Cisapride has a protective effect against TPN-associated cholestasis. This may have clinical significance, and further studies are warranted.

Autologous T cells control B-chronic lymphocytic leukemia tumor progression in human-->mouse radiation chimera

B-chronic lymphocytic leukemia (B-CLL) is characterized by the clonal accumulation of CD5+ B cells. It has been suggested that CLL cells may be regulated by inhibitory and growth-promoting signals exerted by autologous T cells. We have recently described a model for human B-CLL in which peripheral blood mononuclear cells (PBMCs) are transplanted into the peritoneal cavity of lethally irradiated mice radioprotected with bone marrow from mice with severe combined immunodeficiency. In this model, adoptive transfer of low-stage PBMCs leads to marked engraftment of T cells or combined T and CLL cell engraftment, whereas infusion of high-stage PBMCs leads to dominance of CLL cells with a miniscule level of T-cell engraftment. This mutual exclusive pattern of engraftment indicated that T cells might control the expansion of tumor cells in the peritoneum of recipient BALB/c mice. In the present study, we further investigated this question and we demonstrate that in vivo T-cell depletion, using OKT3 antibody, markedly enhances the engraftment of B-CLL cells from patients with early-stage disease. In mice receiving PBMCs from 11 donors with advanced-stage disease, the results were more heterogeneous. In five patients the results were similar to those observed in early stage, whereas in two cases no CLL cell engraftment was found in the absence of T cells. The addition of purified T cells to PBMCs led to a substantial decrease of CLL engraftment in three advanced-stage cases. These results strengthen the working hypothesis that autologous T cells can actively suppress the expansion of the pathological cells in human-->mouse radiation chimera. This effect is prominent in early-stage disease, whereas in advanced stage suppressive and/or stimulatory effects may occur in different patients. The interaction of T cells with tumor cells and the potential of autologous T cell/immune-therapy in CLL can be further explored in this model.

Induction of donor-type chimerism and transplantation tolerance across major histocompatibility barriers in sublethally irradiated mice by Sca-1(+)Lin(-) bone marrow progenitor cells: synergism with non-alloreactive (host x donor)F(1) T cells

Induction of transplantation tolerance by means of bone marrow (BM) transplantation could become a reality if it was possible to achieve engraftment of hematopoietic stem cells under nonlethal preparatory cytoreduction of the recipient. To that end, BM facilitating cells, veto cells, or other tolerance-inducing cells, have been extensively studied. In the present study, we show that BM cells within the Sca-1(+)Lin(-) cell fraction, previously shown to be enriched for early hematopoietic progenitors, are capable of reducing specifically antidonor CTL-p frequency in vitro and in vivo, and of inducing split chimerism in sublethally 7-Gy-irradiated recipient mice across major histocompatibility complex barriers. The immune tolerance induced by the Sca-1(+)Lin(-) cells was also associated with specific tolerance toward donor-type skin grafts. The minimal number of cells required to overcome the host immunity remaining after 7 Gy total body irradiation is very large and, therefore, it may be very difficult to harvest sufficient cells for patients. This challenge was further addressed in our study by demonstrating that non-alloreactive (host x donor)F(1) T cells, previously shown to enhance T-cell-depleted BM allografts in lethally irradiated mice, synergize with Sca-1(+)Lin(-) cells in their capacity to overcome the major transplantation barrier presented by the sublethal mouse model.

Acute cellular rejection of human renal tissue by adoptive transfer of allogeneic human peripheral blood mononuclear cells into chimeric rats: sequential gene expression of cytokines, chemokines and cytolytic effector molecules, and their regulation by CTLA-4-Ig

T(h)1- and T(h)2-related cytokines (IFN-gamma, IL-2, IL-4, IL-10), beta-chemokines (RANTES, macrophage inflammatory protein-1beta) and their receptor [chemotatic cytokine receptor (CCR) 5], and the cytolytic effector molecule [Fas ligand (FasL)] play an essential role in regulating and co-ordinating acute renal allograft rejection. A chimeric model of acute cellular rejection which involves subcapsular grafting of human renal tissue in the kidneys of immunodeficient rats and subsequent i.p. infusion of allogeneic human peripheral blood mononuclear cells (PBMC) was used to study cellular infiltration patterns and sequential intragraft gene expression of these key inflammatory mediators. We found that while all molecules are expressed within the human renal implant at specific time points following infusion of allogeneic human PBMC, peak mRNA expression of IFN-gamma, IL-2, RANTES and CCR5 is associated with a phase of human mononuclear infiltration and accumulation, prior to graft destruction (induction phase). A short burst of FasL gene expression is found at the end of induction and at the onset of graft deterioration. IL-4 mRNA, which is hardly detectable, and IL-10 mRNA, which appears early and persists throughout follow-up at high levels, both peak after the induction phase with the advent of graft destruction. Furthermore, treatment with CTLA-4-Ig, which hardly affects migration of human effector cells into graft tissue, is associated with a temporary reduction in gene transcript levels for all inflammatory mediators, especially IL-2 and IL-4, reduced apoptosis in the graft and amelioration of tissue injury. Thus, development of acute cellular rejection in our chimeric model involves a co-ordinated pattern of gene expression, in which CTLA-4-Ig promotes its effects by transient inactivation of infiltrating human cells.

Intranasal administration of peptide vaccine protects human/mouse radiation chimera from influenza infection

Influenza virus is characterized by frequent and unpredictable changes of the surface glycoproteins which enable the virus to escape the immune system. Approved vaccines which consist of the whole virus or the surface glycoproteins fail to induce broad specificity protection. We have previously reported that a peptide-based experimental recombinant vaccine which includes conserved epitopes of B and T lymphocytes was efficient in mice, leading to cross-strain, long-term protection. In the present study, this approach was adapted for the design of a human vaccine, based on epitopes recognized by the prevalent HLAs. These epitopes were expressed in Salmonella flagellin and tested for their efficacy in human/mouse radiation chimera in which human peripheral blood mononuclear cells (PBMC) are functionally engrafted. The vaccinated mice demonstrated clearance of the virus after challenge and resistance to lethal infection. The production of virus-specific human antibodies was also higher in this group. Control groups of either non-vaccinated, or vaccinated mice which had not been engrafted with the human PBMC, did not exhibit the protective immune response. FACS analysis showed that most human cells in the transplanted mice are CD8(+) and CD4(+). Hence, it may be concluded: (i) that the protection involves cellular mechanisms, but is most probably accomplished without direct lysis of influenza-infected pulmonary cells by cytotoxic T lymphocytes, but rather via a cytokine-mediated mechanism, (ii) that the human/mouse radiation chimera model may be of some value in the investigation of new vaccines, as an additional tool prior to clinical trials, and (iii) that the synthetic recombinant vaccine can induce a response in the human immune system and confers protection against influenza infection. Further investigation is needed to establish the efficacy of such a peptide vaccine in human subjects.

A shared TCR CDR3 sequence in NOD mouse autoimmune diabetes

T cells involved in autoimmune diseases have been characterized by the genetic elements used to construct their autoimmune TCR. In the present study, we sequenced the alpha and beta chains of the TCR expressed by a CD4(+) T cell clone, C9, functional in NOD mouse diabetes. Clone C9 can adoptively transfer diabetes or, when attenuated, C9 can be used to vaccinate NOD mice against diabetes. Clone C9 recognizes a peptide epitope (p277) of the 60 kDa heat shock protein (hsp60) molecule. We now report that the C9 TCR beta chain features a CDR3 peptide sequence that is prevalent among NOD mice. This CDR3 element is detectable by 2 weeks of age in the thymus, and later in the spleen and in the autoimmune insulitis. Thus, a TCR CDR3beta sequence appears to be a common idiotope associated with mouse diabetes.

T cell control of staphylococcal enterotoxin B (SEB) lethal sensitivity in mice: CD4+ CD45RB(bright)/CD4+ CD45RB(dim) balance defines susceptibility to SEB toxicity

Radiation chimeras, generated by transplantation of SCID bone marrow into C3H/HeJ mice, show lethal susceptibility to staphylococcal enterotoxin B (SEB), thus constituting a valid murine model for SEB shock. This SEB sensitivity is due to the ability of the irradiated host to restore residual T cell populations, since the SCID donor bone marrow is unable to generate T cells. SCID bone marrow transplanted into irradiated nude mice does not generate SEB-sensitive chimeras, as a consequence of the inability of the recipient nude mice to develop mature T cells. Thymectomy of normal recipient mice prior to bone marrow transplantation does not affect the development of susceptibility to SEB, suggesting that postthymic, residual T cells of the host probably mediate this SEB sensitivity. In vivo depletion experiments show that CD4+ T cells are required for the SEB-triggered shock, while CD8+ cells suppress it. A further examination of the T helper subpopulations in the SEB-sensitive mice reveals a prevalence of CD4+ CD45RB(dim) cells over CD4+ CD45RB(bright) cells. This T helper balance was statistically significant when correlated with SEB-induced mortality. Our model provides a possible explanation for the SEB resistance of normal mice: they have a prevalence of CD4+ CD45RB(dim) over CD4+ CD45RB(bright) cells.

Antigen-specific B and T cells in human/mouse radiation chimera following immunization in vivo

Adoptive transfer of human peripheral blood mononuclear cells (PBMC) into mice with severe combined immunodeficiency (SCID) or into lethally irradiated BALB/c mice radioprotected with SCID bone marrow, leads to marked engraftment of human T and B cells. In such chimeras, human serum antibody responses can be stimulated readily by vaccination with recall antigens, but the detection of antigen-specific functional T or B cells has been extremely difficult. In the present study, we were able to detect by Elispot analysis high frequencies of immunoglobulin G (IgG)-secreting B cells and mitogen-responsive interferon-gamma (IFN-gamma) or interleukin-4 (IL-4)-secreting T cells in peritoneum and spleen of human/BALB/c chimeric mice during the first 3 weeks after PBMC transfer. Moreover, specific memory responses were elicited by vaccination with tetanus toxoid (TT) or hepatitis B virus (HBV) surface (HBs) antigen of chimeric mice transplanted with PBMC derived from TT- or HBV-immune donors. Substantially higher TT-specific B-cell frequencies were found during the first 3 weeks after vaccination in mice challenged with the specific antigen compared to the levels found in control animals. High numbers of TT-specific IFN-gamma-secreting T cells persisted in the peritoneum of vaccinated, but not of unvaccinated, animals during the entire observation period, but only low numbers of specific IL-4-secreting T cells were found in vaccinated mice. Similar results were achieved following vaccination with HBs antigen of chimeric mice, transplanted with PBMC of HBV immunized donors. Thus, TT or HBsAg-specific antibody responses in our model correlate closely with the existence of specific IFN-gamma-secreting T helper 1/0 cells. Furthermore, these results show that adoptive transfer of human PBMC into lethally irradiated mice provides an efficient approach to generate specific B-cell fusion partners for the production of human monoclonal antibodies and specific T-cell lines for adoptive cell therapy of malignant or infectious diseases.

Human/BALB radiation chimera engrafted with splenocytes from patients with idiopathic thrombocytopenic purpura produce human platelet antibodies

We have previously shown that lethally irradiated normal strains of mice, radioprotected with severe combined immunodeficient (SCID) bone marrow, can be engrafted with human peripheral blood mononuclear cells (PBMC). The human/mouse radiation chimera can mount marked humoral and cellular responses to recall antigens, as well as primary responses. In the present study, we adoptively transferred splenocytes from patients with chronic immune thrombocytopenic purpura (ITP) into lethally irradiated BALB/c mice, radioprotected with SCID bone marrow. High titres of total human immunoglobulin appeared as early as 2 weeks post-transplant and declined after 6 weeks, while human anti-human platelet antibodies were detected 2-8 weeks after the transfer of splenocytes. The immunoglobulin G (IgG) fraction contained antibodies against glycoprotein (GP) IIb/IIIa (CD41) or GPIb/IX (CD42). The human platelet antibodies showed a low level of cross-reactivity with mouse platelets, and thrombocytopenia in the animals was not observed. Splenocytes from individual ITP patients differed in their capacity to produce either human platelet antibodies or total human immunoglobulin. Furthermore, antibodies produced in the murine system were not always identical to the original antibodies present in the serum of the patients. The study of the serological aspects of autoantibodies against human platelets in an animal model might be useful for the investigation of potential therapeutics in ITP.

Tolerance induction by "megadose" hematopoietic transplants: donor-type human CD34 stem cells induce potent specific reduction of host anti-donor cytotoxic T lymphocyte precursors in mixed lymphocyte culture

BACKGROUND

Recently, the use of megadoses of CD34+ hematopoietic progenitors has been reported to abrogate resistance to engraftment, thus overcoming major histocompatibility barriers in bone marrow transplantation in leukemia patients.

METHODS

The ability of human CD34+ cells to possess potent tolerizing activity was studied by limiting dilution analysis of cytotoxic T lymphocyte (CTL) precursors (CTL-p) in human peripheral blood lymphocytes after addition of purified CD34+ cells.

RESULTS

The addition of purified human CD34+ cells to primary mixed lymphocyte culture led to a marked reduction of antiallogeneic CTL-p frequency against stimulator cells of the same origin, compared with the response against cells of third-party origin. The CD34+ cells caused a marked inhibition of the CTL activity, when added at an equal number with the responder T cells, and they were still present after the mixed lymphocyte culture, which suggests that no significant killing of CD34+ cells had occurred. The tolerizing activity is abrogated by irradiation and requires cell contact. This pattern of tolerization most closely resembles what has been ascribed to veto cells in other systems. Phenotypic analysis of the purified CD34+ cells showed that they express MHC class I and class II antigens, but do not express costimulatory molecules of the B7 family.

CONCLUSIONS

It is possible, that CD34+ cells in the megadose transplants-perhaps by their inability to provide costimulatory molecules-are actively reducing the frequency of CTL-p directed against their antigens, and thereby help to overcome allogeneic rejection, and enhance their own engraftment.

Human monoclonal antibodies specific to hepatitis B virus generated in a human/mouse radiation chimera: the Trimera system

An approach to develop fully human monoclonal antibodies in a human/mouse radiation chimera, the Trimera system, is described. In this system, functional human lymphocytes are engrafted in normal strains of mice which are rendered immuno-incompetent by lethal total body irradiation followed by radioprotection with severe combined immunodeficient (SCID) mouse bone marrow. Following transplantation, human lymphocytes colonize murine lymphatic organs and secrete human immunoglobulins. We have established this system as a tool to develop fully human monoclonal antibodies, and applied it for the generation of monoclonal antibodies specific for hepatitis B virus surface antigen. A strong memory response to hepatitis B surface antigen was elicited in Trimera engrafted with lymphocytes from human donors positive for antibodies to hepatitis B surface antigen. The human specific antibody fraction in the Trimera was 10(2)-10(3)-fold higher as compared with that found in the donors. Spleens were harvested from Trimera mice showing high specific-antibody titres and cells were fused to a human-mouse heteromyeloma fusion partner. Several stable hybridoma clones were isolated and characterized. These hybridomas produce high-affinity, IgG, anti-hepatitis B surface antigen antibodies demonstrating the potential of the Trimera system for generating fully human monoclonal antibodies. The biological function and the neutralizing activity of these antibodies are currently being tested.

Engraftment of human kidney tissue in rat radiation chimera: I. A new model of human kidney allograft rejection

BACKGROUND

We have recently shown that lethally irradiated normal strains of mice and rats, reconstituted with bone marrow from severe combined immune deficiency (SCID) mice, can be engrafted with human peripheral blood mononuclear cells (PBMC).

METHODS

The feasibility of transplanting human renal tissue under the kidney capsule of the SCID/Lewis and SCID/nude radiation chimera and the effects of intraperitoneal infusion of allogeneic human PBMC on the human renal implants were investigated by histology, electron microscopy, immunohistochemistry, and fluorescence-activated cell sorter analysis.

RESULTS

Sequential evaluation of the human renal implants from 10 days to 2 months after transplantation showed that human parenchymal elements survive in the implants up to 2 months after transplantation. The overall architecture of the transplanted kidney tissue and the normal structure of individual cells in the glomeruli and tubuli were preserved. Infusion of allogeneic human PBMC after kidney implantation resulted in patchy cellular infiltrates, composed mainly of activated human T cells, and led to prompt rejection of the human renal tissue, whereas no signs of inflammation were observed in human renal implants of chimeric rats that did not receive human PBMC. Treatment with OKT3 antibody, anti-human CD25 antibody, or CTLA4Ig fusion protein in vivo ameliorated the rejection process.

CONCLUSIONS

Human adult kidney fragments transplanted into SCID-like rats transiently retain competent parenchymal structures. When these grafts are combined with allogeneic human PBMC, acute cellular rejection develops. We suggest that this chimeric model might be useful for the investigation of the effects of experimental manipulation on the kinetics of the inflammatory response during human renal allograft rejection.

Engraftment of human kidney tissue in rat radiation chimera: II. Human fetal kidneys display reduced immunogenicity to adoptively transferred human peripheral blood mononuclear cells and exhibit rapid growth and development

BACKGROUND

Transplantation of human kidney tissue under the kidney capsule of immunodeficient animals (severe combined immunodeficiency [SCID]/Lewis and SCID/nude chimeric rats), and the subsequent intraperitoneal infusion of allogeneic human peripheral blood mononuclear cells (PBMC), results in a rapid and consistent human renal allograft rejection. We investigated the consequences of grafting human fetal kidney fragments instead of the adult tissue.

METHODS

The development of human fetal kidney tissue and its interaction with allogeneic human PBMC in chimeric rats were analyzed by histology, immunohistochemistry, and in situ hybridization.

RESULTS

We report successful establishment of human fetal kidney to SCID/Lewis and SCID/nude chimeric rats. The intrarenal human fetal renal implants displayed rapid growth and maintained numerous developing glomeruli and tubular structures up to 4 months after transplantation. In contrast to the adult human kidney, infusion of allogeneic human PBMC resulted in either minimal human T-cell infiltration or abundant nonrejecting T-cell infiltrates, characterized by a reduced number of T cells of the CD45RO+ or HLA-DR+ subsets, both leading to less tissue destruction as well as to continued growth of the human fetal renal tissue. This observation was found to be related to the reduced protein expression of tissue HLA class I and II, intercellular adhesion molecule 1, and vascular adhesion molecule 1 in the fetal grafts compared with the adult grafts. Lack of tissue expression of Fas ligand in the fetal grafts suggests that the latter does not contribute to the delayed rejection of human fetal kidneys.

CONCLUSIONS

Our model should be useful for the study of human fetal renal development and the human alloresponse against fetal tissue.

Human T cells recovered from human/Balb radiation chimeras are hypersensitive to human immunodeficiency virus type 1 infection

Replication of human immunodeficiency virus type 1 (HIV-1) is regulated by virus-encoded regulatory proteins, as well as by a variety of cellular factors. Productive infection of human T lymphocytes by HIV-1 is dependent upon the activation status of the target cells. In general, short-term mitogenic stimulation of CD4 T cells is used to enhance infection of peripheral blood mononuclear cells (PBMC) in vitro. Recently, we demonstrated that adoptive transfer of human PBMC into lethally irradiated BALB/c mice, radioprotected with severe combined immunodeficiency (SCID) mouse bone marrow, leads to marked T-cell activation and proliferation. In the present study, we investigated the effect of such xenoactivation of human T cells on their susceptibility to HIV-1 infection. Human cells that were recovered from human/Balb radiation chimeras supported efficient replication of laboratory strains of HIV-1, as well as of HIV-1 clinical isolates. The multiplicity of infection required to attain effective virus replication in the recovered xenoactivated human cells was 10- to 100-fold lower than that needed for infection of short- or long-term phytohemagglutinin (PHA)-stimulated blasts or of various T-cell lines. Analysis of human cell surface activation markers has indicated that xenoactivation in the mouse, in contrast to in vitro stimulation with PHA, is associated with a marked downregulation of CD25 (interleukin 2 receptor). Our results demonstrate that human cells recovered from human/Balb radiation chimeras, which are hypersensitive to HIV-1 infection, differ from in vitro-stimulated cells in their activation status. Therefore, this system could be used to study host factors that participate in HIV-1 infection and replication in vitro and in vivo.

Human/mouse radiation chimera generated from PBMC of B chronic lymphocytic leukemia patients with autoimmune hemolytic anemia produce anti-human red cell antibodies

Previous studies performed in our laboratory have shown that B-CLL cells are involved in the production of anti-red cell auto-antibodies, providing a possible mechanism for the autoimmune hemolytic anemia occurring during the course of B-CLL. In order to confirm this hypothesis, we attempted to transfer human B-CLL with AIHA to immunodeficient mice. Peripheral blood mononuclear cells (PBMC) from 11 B-CLL patients suffering from AIHA were transplanted into the peritoneal cavity of lethally irradiated Balb/c mice reconstituted with SCID bone marrow. Chimeric mice generated from PBMC of these patients (in stage III-IV of the disease) exhibited an engraftment profile with dominance of tumor cells and minuscule levels of T cells. Eighty-five percent of the chimeric mice generated from 10 out of the 11 B-CLL patients with Coombs'-positive AIHA, produced human Ig with anti-human red cell specificity as detected by indirect anti-globulin test. In addition, anti-red cell auto-antibodies were produced in 36% of chimeric mice generated from PBMC of Coombs'-negative B-CLL. In contrast, control experiments in which splenic cells from idiopathic AIHA or PBMC from normal donors were transplanted, failed to produce anti-RBC. This in vivo model further supports the relationship between the B cell expansion and the autoimmune hemolytic process.

Engrafted human T and B lymphocytes form mixed follicles in lymphoid organs of human/mouse and human/rat radiation chimera

BACKGROUND

We recently described a new approach that enables the generation of human/mouse chimera by adoptive transfer of human peripheral blood mononuclear cells into lethally irradiated normal strains of mice or rats, radioprotected with bone marrow from donors with severe combined immune deficiency. In such human/mouse chimera, a marked humoral response to recall antigens, as well as a significant primary response to keyhole limpet hemocyanin, has been generated.

METHODS

In the present study, the organ distribution of the engrafted human cells in the human/mouse and human/rat chimera was investigated by immunohistochemistry.

RESULTS

Our results show that the T cells seem to be distributed throughout the reticular endothelial system, almost behaving like particles without any homing specificity. The B cells, however, can barely be found in internal organs, such as the liver or the pancreas, and are concentrated in the secondary lymphoid system (e.g., spleen, lymph node, and nonencapsulated lymphoid tissue). The B cells, together with the engrafted human T cells, form mixed lymphoid follicles.

CONCLUSIONS

The different homing patterns exhibited by the T and B lymphocytes indicate that the homing receptors on human B cells might be cross-reactive with their mouse counterparts, in contrast to the human T cells, which seem to be unable to interact with the mouse homing receptors. The presence of human B and T lymphocytes in close proximity to each other in the lymphoid tissues is in accordance with the ability of human/BALB radiation chimera to mount significant primary human antibody responses.

A model for human B-chronic lymphocytic leukemia in human/mouse radiation chimera: evidence for tumor-mediated suppression of antibody production in low-stage disease

B-chronic lymphocytic leukemia (BCLL) is a lymphoproliferative disease that is characterized by clonal expansion of CD5+ B cells. BCLL is associated with secondary immunodeficiency and hypogammaglobulinemia. It has been suggested that T-cell dysregulation may play a role in the hypogammaglobulinemia and in the increased incidence of autoimmunity in BCLL patients. We attempted to transfer human peripheral blood mononuclear cells (PBMC) from BCLL patients in different stages of the disease into immunodeficient mice. PBMC from BCLL patients in stage 0, stages I to II, and stages III to IV were transplanted into the peritoneal cavity of lethally irradiated Balb/c or beige/nude/Xid (BNX) mice radioprotected with bone marrow (BM) from severe combined immunodeficiency (SCID) mice. Different engraftment profiles were found in the chimeric mice 2 weeks after transplantation of PBMC according to the disease stage of the BCLL donors. Infusion of PBMC from donors in stage 0 led to marked engraftment of human T cells, whereas the human tumor cells could hardly be detected. In contrast, chimeric mice receiving PBMC from patients in stage III to IV disease exhibited engraftment with a dominance of tumor cells, compared with a miniscule level of T cells. The ability of the engrafted cells to produce human Ig was also found to be correlated with the disease stage of the donor, although all donors had the same magnitude of hypogammaglobulinemia. Total human Ig production in the chimeric mice was normal in mice receiving PBMC from donors in stage 0, whereas in chimeric mice engrafted with PBMC from donors in stages III to IV almost no human Igs could be detected. This differential reconstitution of antibody production in the mouse model according to the stage of the patient's disease will allow further studies on possible cellular interactions between malignant and immune cells in BCLL.

The choleretic effect of nonsteroidal anti-inflammatory drugs in total parenteral nutrition-associated cholestasis

Cholestasis is a frequent problem in patients on total parenteral nutrition (TPN) therapy. Nonsteroidal anti-inflammatory drugs (NSAIDs), especially aspirin, cause choleresis in animals. We studied the effect of aspirin on bile flow and bile salt secretion in TPN-associated cholestasis in rats. Four groups of 6-10 animals each received either 154 mM NaCl (saline) or 2.5% amino acid solution (TRAVASOL, Travenol, Israel) and 10% glucose i.v. (TPN) for 3 h. During the second and third hours, taurocholate, the main bile salt in rats, was infused at a rate of 10 micromol/min per kg to prevent bile salt pool depletion. Aspirin, one of the main NSAIDs, was infused during the last 2 h into animals with or without TPN treatment at a rate of 100 mg/kg. Bile was directly collected from the common bile duct for 3 h. Rats given TPN showed a significant reduction in bile flow and bile salt secretion rate compared to control groups: 20.89 vs. 29.60 microl/min per kg (P <0.02) and 0.37 vs. 0.65 micromol/min per kg (P <0.0001), respectively. Aspirin had a significant choleretic effect and was able to overcome the bile flow and bile salt secretion rate reduction caused by TPN; 33.07 vs. 20.89 microl/min per kg (P <0.002) and 0.66 vs. 0.37 micromol/min per kg (P <0.0001), respectively. These results may have clinical implications for TPN-associated cholestasis.

Generation of primary antigen-specific human cytotoxic T lymphocytes in human/mouse radiation chimera

Severe combined immunodeficient (SCID) mice are increasingly used as hosts for the adoptive transfer of human lymphocytes. Human antibody responses can be obtained in these xenogeneic chimeras, but information about the functionality of the human T cells in SCID mice is limited and controversial. Studies using human peripheral blood lymphocytes (PBL) injected intraperitoneally (IP) into SCID mice (hu-PBL-SCID mice) have shown that human T cells from these chimeras are anergic and have a defective signaling via the T-cell receptor. In addition, their antigenic repertoire is limited to xenoreactive clones. In the present study, we tested the functionality of human T cell in a recently described chimeric model. In this system, BALB/c mice are conditioned by irradiation and then transplanted with SCID bone marrow, followed by IP injection of human PBL. Our experiments demonstrated that human T cells, recovered from these hu-PBL-BALB mice within 1 month posttransplant, proliferated and expressed activation markers upon stimulation with anti-CD3 monoclonal antibody. A vigorous antiallogeneic human cytotoxic T-lymphocyte (CTL) response could be generated in these mice by immunizing them with irradiated allogeneic cells. Moreover, anti-human immunodeficiency virus type 1 (HIV-1) Net-specific human CTLs could be generated in vivo from naive lymphocytes by immunization of mouse-human chimeras with a recombinant vaccinia-nef virus. This model may be used to evaluate potential immunomodulatory drugs or cytokines, and could provide a relevant model for testing HIV vaccines, for production of antiviral T-cell clones for adoptive therapy, and for studying human T-cell responses in vivo.