A Pilot Study to Evaluate a New Hep-GRP Care Pathway to Improve Outcomes Among Canadian Older Adults with Liver Cirrhosis

Background

Older adults with cirrhosis have complex medical needs that are not satisfied by organ specific management. Interdisciplinary approach may mitigate comorbidity and improve patient satisfaction.

Methods

A pilot study consisted of dual specialist interdisciplinary referral pathway and mixed virtual care delivery model are prospectively evaluated in older adults (65 years and older) with cirrhosis during the COVID-19 pandemic between September and December 2022. Participant attitudes towards telemedicine were surveyed.

Results

68 participants with cirrhosis were consecutively assessed by hepatology. The mean age was 73 years. 39 (57%) screened positive for one or more geriatric syndrome(s). Comprehensive geriatric assessments were conducted via telemedicine in 18 participants, with additional referrals to physiotherapy and nutritional education. Compared to a historic cohort matched for age, sex, and Child-Pugh class, acute health service utilization measured by ER visits among those received dual specialist interdisciplinary consultation were lowered by 1.11 per patient at three-month follow up period (p = .0006, 95% CI 0.47-1.74). Majority participants (87.6%) preferred telemedicine or mixed method visits.

Conclusion

An interdisciplinary approach to older adults with cirrhosis will likely be beneficial, and routine screening for geriatric syndrome may lead to reduced acute health-care utilization in the short term. Telemedicine and virtual screening tools in seniors should be fully explored to improve access to care.

The Canadian approach to elder financial abuse from a legal and clinical perspective: A narrative review

Elder financial abuse is a growing problem, with significant consequences for society. It is unclear if differences exist in the clinical and legal approach to financial abuse across Canada, thus the purpose of this review. Five databases were searched during the primary literature search. Secondary literature search involved searching grey literature and handpicking references from selected articles. Only articles in English were included. From 10,260 articles initially screened, 30 were included in the review. No literature was identified describing differences in the clinical approach to financial abuse, and no single definition or legislation on financial abuse was identified. Mandatory reporting is required for individuals in a hospital or care facility by only five provinces. This review has identified several important knowledge gaps on the differences in the clinical management of financial abuse, and a lack of definition, legislation and overall mandatory reporting across Canada, which requires further research.

A102 INTERDISCIPLINARY TELEHEALTH REFERRAL PATHWAY AND CONSULTATIONS TO IMPROVE OUTCOMES AMONG CANADIAN OLDER ADULTS WITH LIVER CIRRHOSIS

Background

Telehealth and telemedicine have become indispensable healthcare delivery tools during the COVID-19 pandemic. Older individuals with cirrhosis have complex medical needs that are currently unmet due to the growing disease burden and decreased access to care. Delivering timely specialist care virtually to older adults with cirrhosis will likely be beneficial and acceptable to such patients; however, this has not yet been prospectively evaluated.

Purpose

The primary goal is to pilot the delivery of dual specialist care from a hepatologist and geriatrician, delivered virtually, for older adults living with liver cirrhosis who are at high risk of geriatric syndromes (age >/= 65 with frailty, undifferentiated cognitive impairment from dementia or hepatic encephalopathy, recurrent falls, risk factors for polypharmacy and moderate to severe malnutrition). Care is delivered using a dedicated hepatology-geriatric referral pathway. Primary objectives include evaluating the impact of this approach on emergency care and inpatient utilization, along with patient attitude and satisfaction to the virtual interdisciplinary care delivery model.

Method

This pilot quality improvement study was conducted in Halifax, Nova Scotia. Ethics approval was obtained from the Nova Scotia Health Research Ethics Board and the University of Alberta Research Ethics Board. Fifty to one hundred participants (age 65 years or older with at least one geriatric syndrome; diagnosis of liver cirrhosis by liver elastography or liver biopsy, or Fibrosis-4 Index for Liver Fibrosis greater than three and having radiological features of cirrhosis and/or portal hypertension) were recruited between September 2022 to December 2022 at the time of their hepatology consultation. After consent and screening, each patient underwent a telehealth appointment by zoom with a geriatrician within four weeks of their initial hepatology assessment. Follow-up by telephone using a standardized survey regarding ease of access and quality of their telehealth experience then occurred at 3-4 weeks, 3 months and 6 months for emergency room visits and hospital admission status.

Result(s)

Pending

Conclusion(s)

Pending

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Other

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Pfizer Canada

Disclosure of Interest

J. Zhu Grant / Research support from: Pfizer Canada, F. Carr Grant / Research support from: Pfizer Canada, P. Tian: None Declared, M. McLeod: None Declared, M. MacFarlane: None Declared, S. De Coutere: None Declared, M. Sun: None Declared, K. Peltekian: None Declared

Abstract P148: Glycogen phosphorylase and synthase inhibitors: Novel therapeutic approaches in anaplastic thyroid cancer

Thyroid cancer (TC) is the most common endocrine cancer. Effective treatment options for papillary (PTC) and follicular (FTC) thyroid cancers afford positive patient prognoses. However, there are no effective, long-lasting treatments for anaplastic thyroid cancer (ATC), which has a median survival of five to six months. While the receptor tyrosine kinase inhibitor sorafenib can extend ATC patient survival to eleven months, tumor reoccurrence and drug resistance often develop. Therefore, there is a need for more effective targeted therapies for ATC. While the cell signaling landscape is well described in ATC, little is known about tumorigenic adaptations in ATC metabolism. Tumors exhibit an increased consumption of glucose compared to normal tissues to fuel tumor progression. Some cancers meet this high glucose requirement by storing and breaking down glycogen. While glycogen has been detected in bovine and canine thyroids, no report thus far has investigated glycogen in normal human thyroids or thyroid cancer. Therefore, our objective was to determine if normal thyroid and TC cells metabolize glycogen and to evaluate pharmacological inhibition of glycogen metabolism in ATC cells. We show for the first time that normal thyroid, PTC, FTC, and ATC cells express glycogen synthase and glycogen phosphorylase brain and liver (PYGB, PYGL) isoforms. We confirmed these observations in patient samples of normal thyroid and TC tissues via immunofluorescence. We revealed that the TC samples expressed high levels of PYGB compared to normal thyroid tissue. Electron microscopy revealed that normal thyroid cells organized glycogen in discrete glycosomes, while ATC cells exhibited smaller, dispersed glycogen packets. Importantly, we demonstrated that the glycogen synthase inhibitor guaiacol depleted glycogen content and reduced ATC cell viability. Conversely, the glycogen phosphorylase inhibitor CP-91,149 (CP) increased glycogen levels and induced apoptosis. Importantly, CP also reduced the number of stem cells in the ATC cell population. We further showed that CP synergized with sorafenib to more effectively inhibit ATC proliferation. CP enhanced glycolysis but inhibited oxidative phosphorylation as revealed using Seahorse. We confirmed an increase in glucose transporter expression using RT-qPCR and glucose import following CP treatment. This possibly represents a futile response to PYGB inhibition. We reasoned that glycogen was preferentially metabolized in ATC to fuel the pentose phosphate pathway to protect against reactive oxygen species (ROS). Indeed, we detected significantly higher levels of ROS in ATC cells treated with CP. We demonstrated that thyroid cells are able to metabolize glycogen and identified a potential biomarker for thyroid cancer (PYGB), which was targeted with CP-91,149. Our work establishes glycogen metabolism as a novel metabolic process in thyroid cells that is associated with TC dedifferentiation and provides insight to the effectiveness of inhibiting glycogen metabolism as a novel therapeutic strategy in ATC.

Citation Format: Cole Davidson, Jennifer Tomczak, Eyal Amiel, Frances Carr. Glycogen phosphorylase and synthase inhibitors: Novel therapeutic approaches in anaplastic thyroid cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P148.

Targeting Glycogen Metabolism as a Novel Therapeutic Approach in Anaplastic Thyroid Cancer

Effective treatment options for well-differentiated papillary (PTC) and follicular (FTC) thyroid cancers afford positive patient prognoses. The absence of effective interventions for the stem-like, dedifferentiated anaplastic thyroid cancer (ATC) results in poor patient outcomes with a mortality rate higher than all other endocrine cancers combined (1). While receptor tyrosine kinase inhibitors such as sorafenib can extend ATC patient survival, drug resistance and tumor reoccurrence often develop (2). Therefore, there is a critical need for more effective targeted therapies for ATC. Although the cell signaling landscape of ATC tumors is well described, very little is known about tumorigenic adaptations in ATC cellular metabolism. Tumors exhibit an increased consumption of glucose compared to normal tissues to fuel tumor progression. Some cancers meet this high glucose requirement by storing and breaking down glycogen. In our studies here, we show for the first time that normal thyroid, PTC, FTC, and ATC cells express genes necessary for glycogen metabolism. We confirm these observations in patient samples in normal thyroid and thyroid cancer patient samples via immunofluorescence in tissue microarrays. Furthermore, we detect intracellular glycogen stores in cell lines representing normal thyroid, PTC, FTC, and ATC cells. Importantly, we demonstrate that glycogen phosphorylase inhibitors result in accumulation of intracellular glycogen and induce subsequent apoptosis in ATC cells. We further show that glycogen phosphorylase inhibitors synergize with kinase inhibitors such as sorafenib and buparlisib to decrease ATC cell viability. Our work establishes glycogen metabolism as a novel metabolic process in thyroid cells that is associated with thyroid cancer dedifferentiation and provides insight to the effectiveness of inhibiting glycogen metabolism as a therapeutic strategy in ATC.

References: 1. Siegel, R.L., Miller, K.D. and Jemal, A. (2017), Cancer statistics, 2017. CA: A Cancer Journal for Clinicians, 67: 7-30. doi:10.3322/caac.21387

2. Saini S, Tulla K, Maker AV, Burman KD, Prabhakar BS. Therapeutic Advances in Anaplastic Thyroid Cancer: A Current Perspective. Mol Cancer. 2018;17(1):154. doi:10.1186/s12943-018-0903-0

Developing a Decision-Making Capacity Assessment Clinical Pathway for Use in Primary Care: a Qualitative Exploratory Case Study

Background

With an ageing population, the incidence of dementia will increase, as will the number of persons requiring decision-making capacity assessments. For over 10 years, we have trained family physicians in conducting decision-making capacity assessments. Physician feedback post-training, however, has highlighted the need to integrate the decision-making capacity assessment process into the primary care context. The purpose of this study was to develop a decision-making capacity assessment clinical pathway for implementation in primary care.

Methods

A qualitative exploratory case-study design was used to obtain participants’ perspectives regarding the utility of a visual algorithm detailing a decision-making capacity assessment clinical pathway for use in primary care. Three focus groups were conducted with family physicians (n=4) and allied health professionals (n=6) in two primary care clinics in Alberta. A revised algorithm was developed based on their feedback.

Results

In the focus groups, participants identified inconsistencies and a lack of standardization regarding decision-making capacity assessments within primary care, and provided feedback regarding a decision-making capacity assessment clinical pathway to make it more applicable to primary care. Participants described this pathway as appealing and straightforward; they also made suggestions to make it more primary care-centric. Participants indicated that the presented pathway would improve teamwork and standardization of decision-making capacity assessments within primary care.

Conclusions

Use of a decision-making capacity assessment clinical pathway has the potential to standardize decision-making capacity assessment processes in primary care, and support least intrusive and least restrictive patient outcomes for community-dwelling older adults.

Incidence and predictors of postoperative delirium in the older acute care surgery population: a prospective study

Background

Among older inpatients, the highest incidence of delirium is within the surgical population. Limited data are available regarding postoperative delirium risk in the acute care surgical population. The purpose of our study was to establish the incidence of and risk factors for delirium in an older acute care surgery population.

Methods

Patients aged 65 years or more who had undergone acute care surgery between April 2014 and September 2015 at 2 university-affiliated hospitals in Alberta were followed prospectively and screened for delirium by means of a validated chart review method. Delirium duration was recorded. We used separate multivariable logistic regression models to identify independent predictors for overall delirium and longer episodes of delirium (duration ≥ 48 h).

Results

Of the 322 patients included, 73 (22.7%) were identified as having experienced delirium, with 49 (15.2%) experiencing longer episodes of delirium. Postoperative delirium risk factors included Foley catheter use, intestinal surgery, gallbladder surgery, appendix surgery, intensive care unit (ICU) admission and mild to moderate frailty. Risk factors for prolonged postoperative delirium included Foley catheter use and mild to moderate frailty. Surgical approach (open v. laparoscopic) and overall operative time were not found to be significant.

Conclusion

In keeping with the literature, our study identified Foley catheter use, frailty and ICU admission as risk factors for delirium in older acute care surgical patients. We also identified an association between delirium risk and the specific surgical procedure performed. Understanding these risk factors can assist in prevention and directed interventions for this high-risk population.

Deprescribing benzodiazepines among hospitalised older adults: quality improvement initiative

Benzodiazepines are recognised as being potentially inappropriate medications for seniors due to their considerable side-effect profile, yet they are commonly prescribed and infrequently discontinued (deprescribed). The study’s primary objective was the deprescription or the dose reduction of benzodiazepines among newly hospitalised seniors using a patient education intervention. A 3-month duration quality improvement study based on the plan–do–study–act model was conducted across two units (3C and 4D) in the Glenrose Rehabilitation Hospital to improve benzodiazepine deprescribing among newly admitted seniors (65 years or older) who were using benzodiazepines. The primary outcome measure was the number of eligible patients who had benzodiazepine deprescribing initiated. A patient education intervention comprising a structured medication review, written patient education (the Eliminating Medications Through Patient Ownership of End Results (EMPOWER) brochure) and at least one brief supportive counselling session by the clinical pharmacist or physician was applied to all eligible patients. All 12 eligible patients consented to benzodiazepine deprescribing; however, only 11 of them (92%) initiated benzodiazepine deprescribing. Six of the 11 patients (55%) had their benzodiazepines discontinued, with the 5 remaining patients (45%) achieving greater than 50% dosage reduction. Seven patients (64%) experienced side effects during the deprescribing process, with over half (57%, n=4) of these seven patients experiencing worsening anxiety symptoms. Five of the 11 patients (45%) required benzodiazepine substitute medications. The use of a structured patient education intervention involving the use of a structured medication review, written patient education material and one-on-one patient counselling can promote benzodiazepine deprescribing. Although worsening anxiety was frequently observed, this was easily managed by the substitution of a more appropriate and clinically indicated medication, which was well tolerated and acceptable by all of our participants. Targeted screening for the presence of anxiety would help to guide the deprescribing process and the need for medication substitution.

SAT-571 Restoration of Thyroid Hormone Receptor Beta Signaling Reprograms Anaplastic Thyroid Cancer Cells

Anaplastic thyroid cancer (ATC) is among the most lethal human cancers, with an average survival time of six months. These tumors are characterized by rapid local extension, resistance to radioactive iodine therapy and mainstream chemotherapy, and distant metastasis. There are very limited treatment options for this aggressive form of thyroid cancer, highlighting a need for a deeper understanding of its mechanisms for development of new targeted therapies. Loss of expression of the thyroid hormone receptor beta (TRβ) is correlated with aggressive disease and decreased survival in other human cancer types, including breast cancer, hepatocellular carcinoma, and melanoma, suggesting a tumor suppressor role^1-3. Decreased TRβ expression is observed in patients with ATC via tissue microarray⁴ and in representative ATC cell lines⁵. To test the hypothesis that rescue of TRβ can restore a tumor suppressor program and a more differentiated phenotype in ATC cells, we re-introduced constitutive TRβ expression in the SW1736 ATC cell line by stable lentiviral transduction. Proliferation assays reveal that SW1736 cells expressing TRβ have a 30% decrease in proliferation rate compared to empty vector control cells. This prompted us to examine the differences in the transcriptome between our SW1736 cells expressing TRβ and the empty vector control cells to determine the potential mechanisms underlying this observation. Establishment of TRβ expression restored a transcriptional response to thyroid hormone treatment, in concordance with our proliferation studies. Upon transcript quantitation and downstream pathway analysis, we observed changes in several pathways that are well known to influence thyroid cancer growth, including mTOR, PTEN, and TGFβ signalling. Upstream regulators of this transcriptional response included many epigenetic regulators, most notably BRG1, KDM5B, and BRD4. This suggests that restoration of TRβ signalling results in a ligand-dependent chromatin remodeling response to facilitate the gene expression changes we observed. In addition, we measured changes in markers of thyroid differentiation by qPCR and found that TRβ expression and treatment with thyroid hormone increased expression of several key genes including TPO, DIO1, and NIS. In summary, our data support a role for TRβ as a tumor suppressor and mediator of thyroid differentiation in thyroid cells. Importantly, our analyses will direct further investigation into targets and pathways that can be exploited as therapeutic strategies in ATC. 1. Martinez-Iglesias, O. et al.Cancer Res69, 501-509, (2009). 2. Aranda, A. et al. Trends in endocrinology and metabolism: TEM20, 318-324, (2009). 3. Suzuki, H., et al. Thyroid12, 963-969, (2002). 4. Landa, I. et al.J Clin Invest126, 1052-1066, (2016). 5. Carr, F. E. et al.Endocrinology157, 3278-3292, (2016).

Financial and legal decision-making capacity in the aphasic population - a narrative review

INTRODUCTION

Capacity is assumed to be present unless proven otherwise. Assessments of specific decision-making capacity for financial and legal decisions, although challenging in the general population, becomes almost impossible for individuals with language disorders (i.e. aphasia) in the absence of appropriate communication aids. Several capacity aids exist for the general population; however, it is unclear whether any communication aids exist specifically for the aphasic population to assist assessment of financial and legal decision-making capacity.

METHOD

A literature review was conducted of six databases with the assistance of a research librarian. From 171 articles screened, 12 were included in the final review.

RESULTS

The literature focus was on medical decision-making capacity, and in particular, patient consent. Few articles addressed legal or financial decision-making capacity. Several articles identified the presence of general and specific capacity aids for the general population; however, there was a clear absence of similar communication aids available for the aphasic population with only one communication aid identified to assist with decision-making capacity assessment for healthcare and accommodation decisions only.

CONCLUSION

Whilst a significant amount of research has been done on decision-making capacity, it is mostly focused on healthcare; in particular, on patient consent for treatment for the non-aphasic population. Although a communication aid exists to aid assessment of decision-making capacity for healthcare for aphasic individuals, no similar tools exist to aid financial and legal decision-making capacity assessments. This paper highlights an important problem encountered during clinical practice which requires further research.

The 'hidden' SAPHO syndrome

A 64-year-old woman presented to our clinic with a 4-year history of cognitive decline. The clinical examination revealed an incidental finding of the 'SAPHO' (Synovitis Acne Pustulosis Hyperostosis Osteitis) syndrome which was subsequently confirmed by diagnostic imaging. Owing to her classical presentation and her asymptomatic status she was managed conservatively with observation without any complication.

Pain and depression predict self-reported fatigue/energy in lupus

This study examined the contribution of pain and psychological distress to fatigue.

METHODS

One-hundred and twenty-five adult Caucasian and Hispanic lupus patients participated in this study. Demographic data, patient- and physician-reported disease activity, as well as psychological functioning, were collected. Fatigue, pain, and vitality were measured using visual analogue scales as well as a subscale of the SF-36 questionnaire. Linear and hierarchical regression analyses were conducted. In the regression analysis, ethnicity was entered at the first step, followed by age, income and education at step 2, pain and disease activity measures at step 3, and psychological measurements at step 4.

RESULTS

In the linear regression analysis, Caucasians reported more fatigue. Fatigue positively correlated with income, education, pain, patient-reported disease activity, helplessness, and depression, and negatively with internality, and the energy analysis mirrored the results of the fatigue analysis. In the first regression analysis, fatigue was the dependent variable. At step 1, Caucasians reported more fatigue. At step 2, no other demographic variables were significant. At step 3, pain and disease activity measures were significant when entered as a block; however, pain independently explained a large amount of variance. At step 4, psychological factors were significant as a block, with depression being the strongest predictor. In the second analysis, energy was the dependent variable. At step 1, Hispanics reported more energy. At step 2, demographic variables were not significant. At step 3, pain and disease activity were significant when entered as a block; however, only pain uniquely predicted energy. At step 4, psychological factors were significant as a block, with depression as the major contributor.

CONCLUSIONS

Both pain and depression were found to be strong predictors of fatigue, and negatively correlated with energy. Disease activity did not appear to play a significant role in lupus fatigue. These findings support the importance of managing depression and pain in order to reduce fatigue in patients with systemic lupus erythematosus.

An unusual case of renal tubular acidosis

A 40-year-old female with a history of glue sniffing and intravenous drug use presented to hospital with a week's history of feeling generally unwell. She had had multiple admissions to hospital with similar presentations in the past. On examination, the only significant clinical finding was that of a reduced level of consciousness. Laboratory investigations revealed a hyperchloremic normal anion gap metabolic acidosis with a positive urine anion gap and a urine pH of 6.5 combined with a severely low hypokalaemia. She was subsequently diagnosed with renal tubular acidosis type 1, secondary to toluene exposure from glue sniffing and was treated with intravenous fluids and potassium replacement and discharged home with oral potassium citrate and advised to stop her inhalant use.

A novel CEA vaccine stimulates T cell proliferation, γIFN secretion and CEA specific CTL responses

Carcinoembryonic antigen (CEA) is a cell surface protein over-expressed by a wide range of tumours. The mouse anti-idiotypic antibody, 708, mimics CEA and can induce both antibody and T cell responses that specifically recognise this antigen. Sequence analysis of 708 revealed homology with a previously identified HLA-A3 T cell epitope in CEA but not to other closely related molecules. 708 was chimerised to a human IgG1 to allow Fc targeting of APCs and was deimmunised to remove unwanted T cell epitopes. The chimerised and deimmunised, but not the mouse 708, could stimulate CTL, proliferation and gammaIFN responses in vitro in normal (HLA-A3, DR1) individuals. Furthermore, the CTLs killed tumour cells expressing CEA suggesting that this deimmunised antibody could be a useful vaccine for solid tumours.

Altered Na+-K+ pump activity and plasma lipids in salt-hypertensive Dahl rats: relationship to Atp1a1 gene

A genetic variant of the gene for the alpha(1)-isoform of Na(+)-K(+)-ATPase (Atp1a1) was suggested to be involved in the pathogenesis of salt hypertension in Dahl rats through altered Na(+):K(+) coupling ratio. We studied Na(+)-K(+) pump activity in erythrocytes of Dahl salt-sensitive (SS/Jr) rats in relation to plasma lipids and blood pressure (BP) and the linkage of polymorphic microsatellite marker D2Arb18 (located within intron 1 and exon 2 of Atp1a1 gene) with various phenotypes in 130 SS/Jr x SR/Jr F(2) rats. Salt-hypertensive SS/Jr rats had higher erythrocyte Na(+) content, enhanced ouabain-sensitive (OS) Na(+) and Rb(+) transport, and higher Na(+):Rb(+) coupling ratio of the Na(+)-K(+) pump. BP of F(2) hybrids correlated with erythrocyte Na(+) content, OS Na(+) extrusion, and OS Na(+):Rb(+) coupling ratio, but not with OS Rb(+) uptake. In F(2) hybrids there was a significant association indicating suggestive linkage (P < 0.005, LOD score 2.5) of an intragenic marker D2Arb18 with pulse pressure but not with mean arterial pressure or any parameter of Na(+)-K(+) pump activity (including its Na(+):Rb(+) coupling ratio). In contrast, plasma cholesterol, which was elevated in salt-hypertensive Dahl rats and which correlated with BP in F(2) hybrids, was also positively associated with OS Na(+) extrusion. The abnormal Na(+):K(+) stoichiometry of the Na(+)-K(+) pump is a consequence of elevated erythrocyte Na(+) content and suppressed OS Rb(+):K(+) exchange. In conclusion, abnormal cholesterol metabolism but not the Atp1a1 gene locus might represent an important factor for both high BP and altered Na(+)-K(+) pump function in salt-hypertensive Dahl rats.

Human anti-idiotypic antibodies can be good immunogens as they target FC receptors on antigen-presenting cells allowing efficient stimulation of both helper and cytotoxic T-cell responses

Anti-idiotypic antibodies that mimic tumour-associated antigens can stimulate anti-tumour T-cell responses. In this article, we have studied the role of Fc in the presentation of T-cell epitopes by 2 anti-idiotypic antibodies, 105AD7 and 708. The human monoclonal antibody 105AD7, which mimics CD55, stimulated strong in vitro T-cell proliferation, gammaIFN secretion and redirected cytotoxicity in unprimed T cells from healthy donors. However, removal of the Fc region of the anti-idiotype reduced the sensitivity of the assay 1,000-fold, as did inhibiting Fc uptake of the anti-idiotype by an excess of human IgG. The mouse anti-idiotype 708, which mimics CEA, failed to stimulate in vitro T-cell responses on unprimed T cells from healthy donors. However, when a human IgG1 Fc region replaced its mouse Fc region, the anti-idiotype induced T-cell proliferation, gammaIFN secretion and redirected cytotoxicity in lymphocytes from unimmunised donors. Human anti-idiotypes are therefore good immunogens since they target Fc receptors on antigen-presenting cells, allowing efficient stimulation of both helper and cytotoxic T-cell responses. The immunogenicity of other anti-idiotypes may therefore be enhanced by human Fc targeting of antigen-presenting cells.

A novel strategy for the expression of foreign genes from plant virus vectors

Potato virus X (PVX)-based vector constructs were generated to investigate the use of an internal ribosome entry site (IRES) sequence to direct translation of a viral gene. The 148-nucleotide IREScp sequence from a crucifer-infecting strain of tobacco mosaic virus was used to direct expression of the PVX coat protein (CP). The IRES was inserted downstream of the gene encoding green fluorescent protein (GFP) and upstream of the PVX CP, in either sense or antisense orientation, such that CP expression depended on ribosome recruitment to the IRES. Stem-loop structures were inserted at either the 3'- or 5'-end of the IRES sequence to investigate its mode of action. In vitro RNA transcripts were inoculated to Nicotiana benthamiana plants and protoplasts: levels of GFP and CP expression were analysed by enzyme-linked immunosorbent assay and the rate of virus cell-to-cell movement was determined by confocal laser scanning microscope imaging of GFP expression. PVX CP was expressed, allowing cell-to-cell movement of virus, from constructs containing the IRES sequence in either orientation, and from the construct containing a stem-loop structure at the 5'-end of the IRES sequence. No CP was expressed from a construct containing a stem-loop at the 3'-end of the IRES sequence. Our results suggest that the IRES sequence is acting in vivo to direct expression of the 3'-proximal open reading frame in a bicistronic mRNA thereby demonstrating the potential of employing IRES sequences for the expression of foreign proteins from plant virus-based vectors.

Cell-to-cell movement of potexviruses: evidence for a ribonucleoprotein complex involving the coat protein and first triple gene block protein

The triple gene block proteins (TGBp1-3) and coat protein (CP) of potexviruses are required for cell-to-cell movement. Separate models have been proposed for intercellular movement of two of these viruses, transport of intact virions, or a ribonucleoprotein complex (RNP) comprising genomic RNA, TGBp1, and the CP. At issue therefore, is the form(s) in which RNA transport occurs and the roles of TGBp1-3 and the CP in movement. Evidence is presented that, based on microprojectile bombardment studies, TGBp1 and the CP, but not TGBp2 or TGBp3, are co-translocated between cells with viral RNA. In addition, cell-to-cell movement and encapsidation functions of the CP were shown to be separable, and the rate-limiting factor of potexvirus movement was shown not to be virion accumulation, but rather, the presence of TGBp1-3 and the CP in the infected cell. These findings are consistent with a common mode of transport for potexviruses, involving a non-virion RNP, and show that TGBp1 is the movement protein, whereas TGBp2 and TGBp3 are either involved in intracellular transport or interact with the cellular machinery/docking sites at the plasmodesmata.

Analysis of the N gene hypersensitive response induced by a fluorescently tagged tobacco mosaic virus

The hypersensitive response (HR) triggered on Nicotiana edwardsonii by tobacco mosaic virus was studied using a modified viral genome that directed expression of the green fluorescent protein. Inoculated plants were initially incubated at 32 degrees C to inhibit the N gene-mediated HR. Transfer to 20 degrees C initiated the HR, and fluorescent infection foci were monitored for early HR-associated events. Membrane damage, which preceded visible cell collapse by more than 3 h, was accompanied by a transient restriction of the xylem within infection sites. Following cell collapse and the rapid desiccation of tissue undergoing the HR, isolated, infected cells were detected at the margin of necrotic lesions. These virus-infected cells were able to reinitiate infection on transfer to 32 degrees C, however, if maintained at 20 degrees C they eventually died. The results indicate that the tobacco mosaic virus-induced HR is a two-phase process with an early stage culminating in rapid cell collapse and tissue desiccation followed by a more extended period during which the remaining infected cells are eliminated.

Analysis of human TSH receptor gene and RNA transcripts in patients with thyroid disorders

Human TSH receptor (hTSH-R) gene and RNA transcripts were analyzed by Southern and Northern blots in patients with various thyroid disorders, and in tissue cell lines. A 1.4 Kb cDNA encoding the extracellular human TSH-R domain was used as a probe. Southern analysis revealed two constant bands of 11.0 and 5.0 Kb (hTSH-R) in the thyroid and human white cell samples studied, regardless of the disease process. Northern analysis showed a predominant band at about 4.4 Kb in the thyroid tissues but not in non-thyroid tissue or cell lines tested. There were no gene rearrangements or abnormal transcripts in Graves' disease or multinodular goiter samples. In contrast, the labelled cDNA TSH-R probe did not bind to RNA isolated from 1 of 2 papillary cancer samples. A portion of the unique area of the h-TSH receptor (approximately nucleotides 1100-1230) was directly sequenced in thyroid glands from patients with Graves' disease, multinodular goiter, and differentiated thyroid cancer. No mutations or polymorphisms were identified in these samples, as compared to normal thyroid or control placenta, although further definition of sequence variation in other areas of the TSH receptor, as well as in more samples, needs to be performed. The present study indicates the normal patterns of DNA and RNA hybridization in a variety of thyroid tissues and disease states, and demonstrates that pathologic thyroid samples, with the possible exception of thyroid cancer, were not associated with specific nucleotide abnormalities in the unique area of the TSH receptor that was studied.

Genetic transformation of murine bone marrow cells to methotrexate resistance

Genetic transformation of murine bone marrow stem cells to methotrexate resistance was achieved using a modified calcium phosphate-DNA coprecipitation procedure. Bone marrow cells were transformed by DNA derived from methotrexate-resistant mouse 3T6 cells. In vivo selection of drug-resistant bone marrow cells resulted from thrice weekly injections of methotrexate (MTX) for a period of 6-8 wk. Following selection, dihydrofolate reductase activity encoded by the donor DNA species was easily detectable in extracts of recipient mouse spleens. In addition, selection of methotrexate-resistant cells was indicated by the persistence of spleen colony-forming units (CFU-S) in drug-treated animals. Also, changes in ratios of mixed syngeneic bone marrow cells derived from CBA and CBA/T6T6 mice resulted from initial treatment of either cell type with 3T6 DNA. These results confirm and extend the observations of Cline and coworkers that normal bone marrow cells can be genetically transformed to methotrexate resistance.

Effects of lithium on open field behavior in "stressed" and "unstressed" rats

Rats were tested for 3 min per day, for 4 successive days, in an open field apparatus, 20 min after injection of either lithium chloride (2 mEq/kg) or physiological saline. In the first experiment, the open field was illuminated with moderate white light for some rats (stress condition) and dim red light for others (non-stress condition). In the second experiment, some rats received an electric foot shock 5 h before each open field test (stress condition) and others received no foot shock (non-stress condition). In both experiments, lithium significantly reduced rearing behavior in the stressed, but not the unstressed, rats. Lithium also reduced horizontal locomotion, but this effect appeared in both stressed and unstressed rats. In the second experiment, defecation was measured, and it was found that lithium-treated rats defecated less than saline-treated rats in the first session, but not in subsequent sessions, due to habituation which occurred for the saline rats.

Waterborne shigellosis at a public school

In November 1972 an outbreak of gastrointestinal illness occurred at a public school in Stockport, Iowa. One hundred ninety-four (72%) of 269 pupils and 14 (16%) of 23 staff members were affected. The etiologic agent was a strain of Shigella sonnei resistant to multiple antimicrobials. Waterborne transmission of shigellosis was documented epidemiologically and by isolation of the organism from the school water system. Ninety-seven (14%) of 698 of the students' household contacts developed diarrhea, and possible secondary cases also occurred in 3 (9%) of 32 household contacts of school staff.