Clonal Expansion of Stem/Progenitor Cells in Cancer, Fibrotic Diseases, and Atherosclerosis, and CD47 Protection of Pathogenic Cells

We proposed and demonstrated that myelogenous leukemia has a preleukemic phase. In the premalignant phase, normal hematopoietic stem cells (HSCs) gradually accumulate mutations leading to HSC clonal expansion, resulting in the emergence of leukemic stem cells (LSCs). Here, we show that preleukemic HSCs are the basis of clonal hematopoiesis, as well as late-onset blood diseases (chronic-phase chronic myeloid leukemia, myeloproliferative neoplasms, and myelodysplastic disease). The clones at some point each trigger surface expression of "eat me" signals for macrophages, and in the clones and their LSC progeny, this is countered by upregulation of "don't eat me" signals for macrophages such as CD47,opening the possibility of CD47-based therapies. We include evidence that similar processes result in fibroblast expansion in a variety of fibrotic diseases, and arterial smooth muscle clonal expansion is a basis of atherosclerosis, including upregulation of both "eat me" and "don't eat me" molecules on the pathogenic cells.

Crohn's disease: First diagnosis in pregnancy and management

This case addresses the difficulty in the initial diagnosis of severe Crohn's disease in pregnancy as well as the challenges of instituting remission therapy towards the end of second trimester. The patient's course was complicated by recurrent hospital admissions and intolerance to diet requiring temporary nasogastric feeding. Medical management included the use of biological agents during pregnancy, which allowed for better symptomatic control. She sustained no further complications and underwent a successful vaginal delivery of a healthy baby at 37 weeks' gestation.

Small-molecule Hedgehog inhibitor attenuates the leukemia-initiation potential of acute myeloid leukemia cells

Aberrant activation of the Hedgehog signaling pathway has been implicated in the maintenance of leukemia stem cell populations in several model systems. PF‐04449913 (PF‐913) is a selective, small‐molecule inhibitor of Smoothened, a membrane protein that regulates the Hedgehog pathway. However, details of the proof‐of‐concept and mechanism of action of PF‐913 following administration to patients with acute myeloid leukemia (AML) are unclear. This study examined the role of the Hedgehog signaling pathway in AML cells, and evaluated the in vitro and in vivo effects of the Smoothened inhibitor PF‐913. In primary AML cells, activation of the Hedgehog signaling pathway was more pronounced in CD34⁺ cells than CD34⁻ cells. In vitro treatment with PF‐913 induced a decrease in the quiescent cell population accompanied by minimal cell death. In vivo treatment with PF‐913 attenuated the leukemia‐initiation potential of AML cells in a serial transplantation mouse model, while limiting reduction of tumor burden in a primary xenotransplant system. Comprehensive gene set enrichment analysis revealed that PF‐913 modulated self‐renewal signatures and cell cycle progression. Furthermore, PF‐913 sensitized AML cells to cytosine arabinoside, and abrogated resistance to cytosine arabinoside in AML cells cocultured with HS‐5 stromal cells. These findings imply that pharmacologic inhibition of Hedgehog signaling attenuates the leukemia‐initiation potential, and also enhanced AML therapy by sensitizing dormant leukemia stem cells to chemotherapy and overcoming resistance in the bone marrow microenvironment.

A phase I, open-label, dose-escalation, multicenter study of the JAK2 inhibitor NS-018 in patients with myelofibrosis

NS-018 is a Janus-activated kinase 2 (JAK2)-selective inhibitor, targeting the JAK–signal transducer and activator of transcription (STAT) pathway that is deregulated in myelofibrosis. In this phase I, dose-escalation portion of a phase I/II study, patients with myelofibrosis received oral NS-018 in continuous 28-day cycles. The primary study objective was to evaluate safety, tolerability and clinically active dose of NS-018. Forty-eight patients were treated; 23 (48%) had previously received a JAK inhibitor (JAKi). The most common drug-related adverse events were thrombocytopenia (27%)/anemia (15%) for hematologic events, and dizziness (23%)/nausea (19%) for non-hematologic events. Once daily NS-018 at 300 mg was chosen as the phase II study dose based on improved tolerability compared with higher doses. A ⩾50% reduction in palpable spleen size was achieved in 56% of patients (47% of patients with prior JAKi treatment), and improvements were observed in myelofibrosis-associated symptoms. Bone marrow fibrosis grade (local assessment) improved from baseline in 11/30 evaluable patients (37%) after 3 cycles of NS-018. JAK2 allele burden was largely unchanged. Changes in cytokine/protein levels were noted after 4 weeks of treatment. NS-018 reached peak plasma concentration in 1–2 h and did not accumulate with multiple dosing. NS-018 will be assessed in patients with previous JAKi exposure in the phase II portion.

A phase 2 randomized dose-ranging study of the JAK2-selective inhibitor fedratinib (SAR302503) in patients with myelofibrosis

In this phase 2 open-label randomized study, 31 patients with intermediate-2 or high-risk myelofibrosis received fedratinib 300, 400 or 500 mg once daily in consecutive 4-week cycles. Mean spleen volume reductions at 12 weeks (primary end point) were 30.3% (300 mg), 33.1% (400 mg) and 43.3% (500 mg). Spleen response rates (patients achieving ⩾35% spleen reduction) at 12/24 weeks were 30%/30% (300 mg), 50%/60% (400 mg) and 64%/55% (500 mg), respectively. By 4 weeks, improvements in myelofibrosis (MF)-associated symptoms were observed. At 48 weeks, 68% of patients remained on fedratinib and 16% had discontinued because of adverse events (AEs). Common grade 3/4 AEs were anemia (58%), fatigue (13%), diarrhea (13%), vomiting (10%) and nausea (6%). Serious AEs included one case of reversible hepatic failure and one case of Wernicke's encephalopathy (after analysis cutoff). Fedratinib treatment led to reduced STAT3 phosphorylation but no meaningful change in JAK2V617F allele burden. Significant modulation (P<0.05, adjusted for multiple comparisons) of 28 cytokines was observed, many of which correlated with spleen reduction. These data confirm the clinical activity of fedratinib in MF. After the analysis cutoff date, additional reports of Wernicke's encephalopathy in other fedratinib trials led to discontinuation of the sponsored clinical development program.

Chronic myeloproliferative diseases with and without the Ph chromosome: some unresolved issues

Ph-positive chronic myeloid leukemia (CML) and Ph-negative chronic myeloproliferative diseases (MPDs), characterized in many cases by the presence of the JAK2(V617F) mutation, have many features in common and yet also show fundamental differences. In this review, we pose five discrete and related questions relevant to both categories of hematological malignancy, namely: What are the mechanisms that underlie disease progression from a relatively benign or chronic phase? By what therapeutic methods might one target residual leukemia stem cells in CML? Is JAK2(V617F) the original molecular event in MPD? What epigenetic events must have a role in dictating disease phenotype in MPDs? And finally, Will the benefits conferred by current or future JAK2(V617F) inhibitors equal or even surpass the clinical success that has resulted from the use of tyrosine kinase inhibitors in CML? These and others questions must be addressed and in some cases should be answered in the foreseeable future.

TG101348, a potent, highly selective JAK2 inhibitor, inhibits colony formation in stem cells from polycythemia vera patients and prevents JAK2V617F-mediated splenomegaly and death in a mouse model

7031

Background: The molecular pathogenesis of the myeloproliferative disorders (MPDs) polycythemia vera, essential thrombocythemia, and myelofibrosis with myeloid metaplasia has been strongly linked to an activating mutation of JAK2 (Janus Associated Kinase 2). A G-T transversion event in exon 14 that translates into a substitution of phenylalanine for valine at amino acid residue 617 leads to constitutive activation of JAK2V617F in a majority of these MPD cases. Methods: In order to address this unmet clinical need we designed, synthesized and performed preclinical evaluations on a series of structurally novel compounds optimized for JAK2 inhibition. Results: TG101348, a compound which potently inhibits JAK2V617F enzymatically and in human cells, was selected as a clinical development candidate from this medicinal chemistry campaign. TG101348 displays remarkable kinase specificity as shown by 83X selectivity versus JAK3 and potent inhibition of <2% of the kinases evaluated in a commercial, phylogenetically diverse panel of 212 kinases. TG101348 potently inhibits erythroid colony formation in patient-derived cells from polycythemia patients at doses 2–3X lower than in normal control patients. Consistent with this observation TG101348 inhibits JAK2-driven STAT5 phosphorylation, cell proliferation and cell survival in JAK2V617F-expressing cell lines. In vivo, TG101348 exhibits promising pharmacokinetic profiles in species ranging from mouse to monkey including oral availabilities >20%, and half-lives consistent with once or twice daily dosing. TG101348 reduces the number of circulating mutant JAK2 cells, inhibited splenomegaly and improved survival without significantly impacting normal hematocrit in an aggressive JAK2-driven circulating cell model of disease in rodents. Conclusion: TG101348 has considerable potential for the treatment of JAK2- driven myeloproliferative disorders based on its promising preclinical potency, selectivity and pharmaceutical properties.

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Solid-phase development of a L-hydroxybenzotriazole linker for heterocycle synthesis using analytical constructs

The development of a 1-hydroxybenzotriazole linker for the synthesis of heterocyclic derivatives is described, utilizing analytical construct methodology to facilitate the analysis of resin samples. A UV-chromophore-containing analytical construct enabled the accurate determination of resin loading and the automated monitoring of key reactions using only small quantities of resin. The syntheses of an array of isoxazole derivatives are reported.

Development and application of a carbonyl-(13)C-enriched backbone amide linker for solid-phase reaction monitoring

The synthesis and application of a carbonyl-(13)C backbone amide linker are described. The labeled unit is conveniently mixed with commercial resins, providing a rapid means of monitoring chemistry performed with this linker on solid support using conventional (13)C NMR methods.

Capecitabine (Xeloda) improves medical resource use compared with 5-fluorouracil plus leucovorin in a phase III trial conducted in patients with advanced colorectal carcinoma

Standard therapy for advanced or metastatic colorectal cancer consists of 5-fluorouracil plus leucovorin (5-FU/LV) administered intravenously (i.v.). Capecitabine (Xeloda), an oral fluoropyrimidine carbamate which is preferentially activated by thymidine phosphorylase in tumour cells, mimics continuous 5-FU and is a recently developed alternative to i.v. 5-FU/LV. The choice of oral rather than intravenous treatment may affect medical resource use because the two regimens do not require the same intensity of medical intervention for drug administration, and have different toxicity profiles. Here we examine medical resource use in the first-line treatment of colorectal cancer patients with capecitabine compared with those receiving the Mayo Clinic regimen of 5-FU/LV. In a prospective, randomised phase III clinical trial, 602 patients with advanced or metastatic colorectal cancer recruited from 59 centres worldwide were randomised to treatment with either capecitabine or the Mayo regimen of 5-FU/LV. In addition to clinical efficacy and safety endpoints, data were collected on hospital visits required for drug administration, hospital admissions, and drugs and unscheduled consultations with physicians required for the treatment of adverse events. Capecitabine treatment in comparison to 5-FU/LV in advanced colorectal carcinoma resulted in superior response rates (26.6% versus 17.9%, P=0.013) and improved safety including less stomatitis and myelosuppression. Capecitabine patients required substantially fewer hospital visits for drug administration than 5-FU/LV patients. Medical resource use analysis showed that patients treated with capecitabine spent fewer days in hospital for the management of treatment related adverse events than did patients treated with 5-FU/LV. In addition, capecitabine reduced the requirement for expensive drugs, in particular antimicrobials fluconazole and 5-HT3-antagonists to manage adverse events. As anticipated with an oral home-based therapy patients receiving capecitabine needed more frequent unscheduled home, day care, office and telephone consultations with physicians. In the light of clinical results from the phase III trial demonstrating increased efficacy in terms of response rate, equivalent time to progression (TTP) and survival (OS), and a superior safety profile, the results from this medical resource assessment indicate that capecitabine treatment of colorectal cancer patients results in a substantial resource use saving relative to the Mayo Clinic regimen of 5-FU/LV. This benefit is derived principally from the avoidance of hospital visits for i.v. drug administration, less expensive drug therapy for the treatment of toxic side-effects, and fewer treatment-related hospitalisations required during the course of therapy for adverse drug reactions in comparison to patients treated with 5-FU/LV.

Ambulatory blood pressure in heart failure

Ambulatory blood-pressure monitoring (ABPM) is accepted in the evaluation and management of hypertension. The use of ABPM in heart failure has received considerably less attention. Many patients with advanced heart failure experience disabling fatigue, orthostatic dizziness and symptoms of coronary and cerebrovascular insufficiency that may relate to periods of hypotension. These may be exacerbated by vasodilator drug therapy and may be difficult to evaluate by casual clinic recordings. ABPM in heart failure may help in the following: (i) evaluating time-dependent pharmacodynamic drug effects, such as peak and end-of-dose phenomena, tolerance and rebound; (ii) titrating ACE inhibitors and other drugs to highest-tolerated doses; and (iii) correlating circadian blood-pressure profiles with symptoms, quality of life, severity of heart failure, progression of ventricular and renal dysfunction, risks of stroke and myocardial infarction, and life expectancy. Devices for ABPM have been beset by problems of inaccuracy and unreliability. Standards for their manufacture and sale (including bench tests of accuracy against sphygmomanometry and intra-arterial recordings, and field tests of reliability) have been devised independently by several agencies, including the British Hypertension Society (BHS) and US Association for the Advancement of Medical Instrumentation (AAMI). A joint BHS/AAMI set of guidelines is in preparation. These guidelines emphasize the suitability of ABPM devices for hypertensive patients and those under general anesthesia, and may not be applicable to ambulant individuals with heart failure and blood pressures at or below the lower end of the evaluated ranges. Prospective studies of the accuracy and reliability of ABPM devices, their clinical utility and research potential should be undertaken in patients with heart failure before their informal and uncontrolled use in this population becomes widespread.

Inhibition of the ubiquitin-proteasome system in Alzheimer's disease

Alzheimer's disease is the most common cause of dementia in the elderly. Although several genetic defects have been identified in patients with a family history of this disease, the majority of cases involve individuals with no known genetic predisposition. A mutant form of ubiquitin, termed Ub(+1), has been selectively observed in the brains of Alzheimer's patients, including those with nonfamilial Alzheimer's disease, but it has been unclear why Ub(+1) expression should be deleterious. Here we show that Ub(+1) is an efficient substrate for polyubiquitination in vitro and in transfected human cells. The resulting polyubiquitin chains are refractory to disassembly by deubiquitinating enzymes and potently inhibit the degradation of a polyubiquitinated substrate by purified 26S proteasomes. Thus, expression of Ub(+1) in aging brain could result in dominant inhibition of the Ub-proteasome system, leading to neuropathologic consequences.

A new model for recognizing and rewarding the educational accomplishments of surgery faculty

Faculty members' educational endeavors have generally not received adequate recognition. The Association for Surgical Education in 1993 established a task force to determine the magnitude of this problem and to create a model to address the challenges and opportunities identified. To obtain baseline information, the task force reviewed information from national sources and the literature on recognizing and rewarding faculty members for educational accomplishments. The group also developed and mailed to surgery departments at all U.S. and Canadian medical schools a questionnaire asking about the educational endeavors of the surgery faculty and their recognition for such activities. The response rate after two mailings was only 56%, but the responses reaffirmed the inadequacy of systems for rewarding and recognizing surgeon-teachers and surgeon-educators, and confirmed that the distinction between the roles of teacher and educator was rarely made. The task force created a four-tier hierarchical model based on the designations teacher, master teacher, educator, and master educator as a framework to offer appropriate recognition and rewards to the faculty, and endorsed a broad definition of educational scholarship. Criteria for various levels of achievement, ways to demonstrate and document educational contributions, appropriate support and recognition, and suggested faculty ranks were defined for these levels. The task force recommended that each surgery department have within its faculty ranks a cadre of trained teachers, a few master teachers, and at least one educator. Departments with a major commitment to education should consider supporting a master educator to serve as a resource not only for the department but also for the department's medical school and other medical schools. Although this model was created for surgery departments, it is generalizable to other disciplines.

Thyroid xenografts from patients with Graves' disease in severe combined immunodeficient mice and NIH-beige-nude-xid mice

OBJECTIVE

To compare human thyroid xenografts from patients with Graves' disease in severe combined immunodeficient (SCID) mice and triple immunodeficient NIH-beige-nude-xid (NIH-3) mice to obtain an improved animal model for studying these xenografts.

DESIGN

Animal study. PARTICIPANTS AND ANIMALS: Patients with Graves' disease; SCID and NIH-3 mice.

INTERVENTIONS

Thyroid tissue from six patients with Graves' disease was xenografted to SCID and NIH-3 mice; in addition, peripheral blood mononuclear cells (PBMC) from 12 patients with Graves' disease were grafted intraperitoneally to separate SCID and NIH-3 mice.

OUTCOME MEASURES

Levels of human immunoglobulin (IgG), thyroperoxidase antibodies (TPO-Ab), thyroglobulin (Tg-Ab), and expression of thyrocyte intercellular adhesion molecule-1 (ICAM-1) and histocompatibility leukocyte antigen (HLA-DR) in mice after xenografting.

RESULTS

IgG was detected in all mice grafted with Graves' thyroid tissue and some mice grafted with PBMC; levels of human IgG peaked 6 to 10 weeks after xenografting. Human IgG levels reached a mean of 500 mg/L (standard error of the mean [SEM] 150 mg/L) in the NIH-3 mice with thyroid xenografts. This was similar to results in SCID mice with thyroid xenografts, which had a mean level of human IgG of 640 mg/L (SEM 230 mg/L). PBMC xenografting resulted in a mean IgG level of 1200 mg/L (SEM 250 mg/L) in NIH-3 mice, which was similar to the mean level of 1000 mg/L (SEM 280 mg/L) in SCID mice. The rate of rise in human IgG in the sera of the NIH-3 mice with thyroid xenografts was similar to that in the SCID mice. TPO-Ab were also detected in some mice with Graves' thyroid grafts and in a few mice injected with PBMC, with levels peaking 4 to 6 weeks after xenografting. TPO-Ab levels reached a mean 109.3 U/mL (SEM 57.2 U/mL) in the NIH mice with thyroid xenografts, which were similar to the mean level of 91.7 U/mL (SEM 34.2 U/mL) in the SCID mice. There were no significant differences in the Tg-Ab levels in each type of mice (13.9 [SEM 12.1] U/mL v. 17.9 [SEM 7.9] U/mL). Eight weeks after xenografting into mice, the expression of xenograft thyrocyte ICAM-1 decreased significantly in both the SCID and NIH-3 mice (from 43.4%, SEM 4.9%, to 35.9%, SEM 4.6%, in the NIH-3 mice, p < 0.05, and from 43.4%. SEM 4.9%, to 32.5%, SEM 5.2%, in the SCID mice, p < 0.05). However, the expression of thyrocyte HLA-DR did not change significantly in the NIH-3 mice (from 11.5%, SEM 3.3%, to 10.8%, SEM 3.3%), whereas it decreased significantly in the SCID mice (from 11.5%, SEM 3.3%, to 4.2%, SEM 2.0%, p < 0.02).

CONCLUSIONS

Not only SCID mice but also NIH-3 mice may be useful as animal models for xenografted thyroid tissue, which will help us elucidate the pathogenesis of autoimmune thyroid disease. NIH-3 mice are superior to SCID mice in maintaining the expression of thyrocyte HLA-DR in Graves' thyroid xenografts at levels as high as those before xenografting; this maintenance of expression may be due to the lack of natural killer cells in NIH-3 mice.

Teaching effectiveness of surgeons

BACKGROUND

Evaluation of clinical teaching is essential for feedback to teachers, and for reliable and valid data for the purpose of promotion and tenure.

METHODS

The teaching effectiveness of 43 surgeons was evaluated continuously over a 9-year period. Stability of Teaching Effectiveness Scores (TES) over the 9-year period, correlation with age, and the changes after academic promotion were analyzed.

RESULTS

A total of 3,750 evaluations were completed. The average of 10 evaluations per surgeon per year gave an intraclass correlation of 0.65. The mean TES did not show any significant change over the 9 years. The majority of the "good" and "average" surgeons maintained their TES ratings, and most of the "poor" group improved their TES. The age of the surgeon was not a factor. Most surgeons had a decrease in their TES after academic promotion.

CONCLUSIONS

A reliable system of teaching evaluation was achieved. Teaching scores were stable over time for good and average teachers, whereas the poor teachers tended to improve their scores.

Teaching effectiveness of surgeons

BACKGROUND

Evaluation of clinical teaching is essential for feedback to teachers, and for reliable and valid data for the purpose of promotion and tenure.

METHODS

The teaching effectiveness of 43 surgeons was evaluated continuously over a 9-year period. Stability of Teaching Effectiveness Scores (TES) over the 9-year period, correlation with age, and the changes after academic promotion were analyzed.

RESULTS

A total of 3,750 evaluations were completed. The average of 10 evaluations per surgeon per year gave an intraclass correlation of 0.65. The mean TES did not show any significant change over the 9 years. The majority of the "good" and "average" surgeons maintained their TES ratings, and most of the "poor" group improved their TES. The age of the surgeon was not a factor. Most surgeons had a decrease in their TES after academic promotion.

CONCLUSIONS

A reliable system of teaching evaluation was achieved. Teaching scores were stable over time for good and average teachers, whereas the poor teachers tended to improve their scores.

Expression of intercellular adhesion molecule-1 on human thyroid cells from patients with autoimmune thyroid disease: study of thyroid xenografts in nude and severe combined immunodeficient mice and treatment with FK-506

It has been suggested that intercellular adhesion molecule-1 (ICAM-1) may play an important role in the initiation, localization, and perpetuation of autoimmune thyroid diseases (AITD). In an effort to clarify its role, we have investigated the expression of ICAM-1 on thyroid epithelial cells (TEC) of patients with AITD, patients with nontoxic goiter (NTG), and normal subjects (PN) by flow cytometric analysis under basal conditions and after modulation with cytokines, before and after 8 weeks of thyroid tissue xenotransplantation in nude athymic mice (which lyses all passenger lymphocytes), and in severe combined immunodeficient (SCID) mice where these cells survive. Before xenografting, ICAM-1 was expressed on 56% of TEC from Hashimoto's thyroiditis (n = 5), 54% of Graves' disease (n = 6), 15% of NTG (n = 5), and 12% of PN TEC. After the xenografts had been 8 weeks in nude mice, ICAM-1 expression decreased markedly in AITD TEC [from 56% to 10% in Hashimoto's thyroiditis (P < 0.001) and from 54% to 8% in Graves' disease (P < 0.01)], but did not change significantly in NTG or PN. After the xenografts had been 8 weeks in SCID mice, the expression of ICAM-1 was significantly higher on TEC of AITD compared with the same tissue in nude mice. When the SCID mice engrafted with AITD tissue were treated with the anti-CD4+ T (helper) cell agent FK-506, the expression of ICAM-1 was reduced significantly compared with that in the original tissue or that in nontreated mice engrafted with the same tissue. The proportion of TEC that were ICAM-1 positive was up-regulated in all cases by certain cytokines (e.g. interferon-gamma and tumor necrosis factor-alpha applied alone or in combination). We also detected the presence of ICAM-1 in AITD frozen tissues using an immunohistochemical technique. These data suggest a role for ICAM-1 in human AITD. However, the expression of ICAM-1 appears to be a secondary phenomenon in response to the immune assault, rather than a primary event. Our results support the idea that TEC may act as passive captives to immunological events in human AITD.

Selective elimination of malignant stem cells using photosensitizers followed by light treatment

The pros and cons of purging of either bone marrow or peripheral blood stem cell preparations for autologous transplantation for cancer has been debated strongly over the past decade. Recent data implicating the role of minimal residual disease in autografted marrow in cancer relapse have renewed interest in this question. There is a considerable body of literature supporting the possibility that photosensitizer molecules in combination with light might provide a therapeutic window permitting selective elimination of malignant stem cells while sparing those of normal lineage. Molecules of this class are known to be taken up more actively by most malignant cells, and intracellular concentrations are critical in their cytotoxic effect when they are activated by light at an appropriate wavelength. The present paper reviews the observations made over the past decade on a variety of photosensitizers and their effects on hemopoietic progenitors.

Effect of FK-506 on xenografted human Graves' thyroid tissue is severe combined immunodeficient mice

OBJECTIVE

We studied the macrolide antibiotic FK-506, an immunosuppressive agent, in an attempt to ameliorate the lesion of autoimmune thyroid disease in human thyroid tissue xenografted into severe combined immunodeficient (SCID) mice. It was not felt appropriate to employ this agent directly in patients with autoimmune thyroid disease because adequate therapeutic modalities are available and the introduction of new, experimental agents could not be justified. Moreover, the study of the tissue before and after treatment could not have been undertaken directly in patients.

DESIGN

Human thyroid xenografts from four patients with Graves' disease and two normal persons were xenografted into SCID mice. Two weeks after xenografting, human immunoglobulin G (IgG) was detectable in all SCID mice xenografted with Graves' thyroid tissue. Mice were divided into two groups with human IgG levels similar to each other. Mice in the first group were treated with FK-506 daily for 6 weeks; mice in the second (similar) group were given phosphate-buffered saline (PBS) only (control group).

MEASUREMENTS

Blood samples were taken every 2 weeks from the tail veins for human IgG, thyroid stimulating antibody, thyroperoxidase antibodies, thyroglobulin antibodies, and interferon-gamma (IFN-gamma). After 8 weeks treatment, animals were sacrificed; thyroid tissue was examined histologically and for thyrocyte HLA-DR expression. FK-506 was also added to thyrocytes in in-vitro tissue culture conditions.

RESULTS

After 4-6 weeks of FK-506 therapy, human IgG, all thyroid antibodies and IFN-gamma were suppressed, while the levels remained elevated in the control group. Lymphocytic infiltration virtually disappeared in the human thyroid tissue of the FK-506-treated mice and thyrocyte HLA-DR expression markedly declined; in the control mice, lymphocytic infiltration remained heavy and HLA-DR expression remained high. On the other hand, FK-506 added directly to thyrocytes in vitro (without lymphocytes) did not reduce thyrocyte HLA-DR expression.

CONCLUSIONS

FK-506 appears to suppress the activation of intrathyroidal lymphocytes, but not thyrocytes. From these observations, it is concluded that this agent, by its action on intrathyroidal lymphocytes, is able to ameliorate the immunologically mediated histological and serological disturbance in human autoimmune thyroid disease, at least under these circumstances.

Effect of removing human Graves' thyroid xenografts after eight weeks in nude mice and rexenografting them into SCID mice

Human thyroid xenografts from four patients with Graves' disease (GD) and two normal persons were initially xenografted into nude mice. Eight weeks after xenografting, the thyroid tissue appeared normal; indeed, thyroid infiltrating lymphocytes in the GD xenograft could no longer be identified when analyzed histologically. Thus, human immunoglobulin G (IgG), thyroperoxidase (TPO)-antibodies (Abs), thyroglobulin (Tg)-Abs, thyroid-stimulating antibodies (TSAb), and thyrocyte histocompatibility leucocyte antigen (HLA)-DR expression were undetectable. These same tissues were retrieved from the nude mouse and rexenografted into severe combined immunodeficient (SCID) mice (with no prior xenograft); autologous peripheral blood mononuclear cells (PBMC) or CD8-depleted PBMC (non-CD8 cells) were simultaneously injected into some of these SCID mice. Engraftment of a GD thyroid rexenograft (TH) alone did not cause IgG, TSAb, TPO-Ab, or Tg-Ab production, thyrocyte HLA-DR expression, or lymphocytic infiltration in thyroid grafts. Engraftment of GD PBMC or non-CD8 cells alone (i.e. without a thyroid xenograft) caused human IgG to rise, but only minimal titers of thyroid antibodies appeared. When TSAb, TPO-Ab, and Tg-Ab were quantified, GD TH plus PBMC-engrafted SCID mice showed significantly higher production of each antibody than that of GD PBMC alone, and this phenomenon was further enhanced by the removal of CD8+ cells. GD thyrocytes showed marked HLA-DR expression at human surgery; however, after 8 weeks' sojourn in nude mice, DR expression disappeared. After a further 8 weeks following rexenografting into SCID mice, TH plus PBMC resulted in a reappearance of DR expression only in GD but not in grafts from normal persons, and this was enhanced by the depletion of CD8 cells. These results were also in parallel with histological findings inasmuch as the normal tissue remained normal with no thyroid antibodies appearing with PBMC or CD8-depleted cells. In experiments from two GD patients, autologous skeletal muscle as well as thyroid tissue were xenografted into nude mice. Eight weeks after xenografting, these were rexenografted into SCID mice that contained prior autologous primary GD thyroid xenografts. Histological findings showed new lymphocytic infiltration in rexenografted thyroid tissues in the SCID mice but not in autologous skeletal muscle. This signifies that the immune assault in GD is specifically targeted to the thyroid tissue.(ABSTRACT TRUNCATED AT 400 WORDS)

Studies of human thyroid xenografts from Hashimoto's thyroiditis in severe combined immunodeficient (SCID) mice: detection of thyroid stimulation-blocking antibody

Human thyroid xenografts from 7 patients with Hashimoto's thyroiditis (HT) and 3 normal persons (N) were xenografted into severe combined immunodeficient (SCID) mice to study the intrathyroidal lymphocytes that were expected to survive in these animals. Human IgG was detected in all mice engrafted with HT thyroid tissue peaking at 6-10 weeks after xenografting. Thyroperoxidase-antibody (TPO-Ab) was also detected in all mice with HT thyroid grafts peaking at 4-6 weeks after xenografting, reaching up to 44% of donors' original concentrations. In contrast, maximal thyroglobulin (Tg)-Ab production in some SCID mice with HT thyroid grafts was higher than the donors' original level, and was detectable in mice with thyroid grafts from Tg-Ab-negative HT donors. Thyroid stimulation-blocking antibody (TSBAb) was found in 2 mice with thyroid xenografts from 1 HT patient whose original serum TSBAb and thyrotropin-binding inhibitor immunoglobulin (TBII) had been positive; the maximal TSBAb level in SCID mice exceeded the donor's original level. TSBAb production in SCID mice reached its peak at 10 weeks after xenografting, i.e., later than that of thyroid-stimulating antibody (TSAb) observed in our recent report, suggesting the existence of distinct intrathyroidal B cell autoreactive clones of different life span responsible for secreting TSAb or TSBAb. When autologous peripheral blood mononuclear cells (PBMC) were engrafted alone (without thyroid tissue), TSBAb was undetectable.(ABSTRACT TRUNCATED AT 250 WORDS)

Studies of thyroid xenografts from Graves' disease in severe combined immunodeficient mice

Thyroid tissues from normal (paranodular) subjects and patients with Graves' disease (GD) and Hashimoto's thyroiditis (HT) were xenografted to severe combined immunodeficiency (SCID) mice, and the same tissues were engrafted into nude mice; in addition, peripheral blood mononuclear cells were engrafted to separate SCID mice (SCID-PB). Thyroglobulin (TG) and microsomal antibodies (Abs) became detectable with high titers by hemagglutination assays in SCID mice xenografted with thyroid tissues (SCID-TH) from GD and HT patients; moreover, TG Ab was detectable even in SCID-TH from TG Ab-negative GD and HT donors. On the other hand, only 2 of 10 SCID-PB had detectable Abs with low titers. TSH receptor (TSH-R) Ab was detectable in all sets of SCID-TH from GD. After peaking (3-7 weeks), their levels decreased despite the fact that immunoglobulin G levels increased. In addition, in 3 of 4 sets of SCID-PB from GD patients, TSH-R Ab was also detectable. SCID-TH from GD and HT patients showed transient hyperthyroxinemia, peaking at 2 weeks; these values were significantly higher [free T4, 6.48 +/- 0.90 and 5.50 +/- 0.77 pmol/L (mean +/- SE), respectively; P < 0.05] than SCID-TH from normal controls (2.5 +/- 0.24). Histologically, intrathyroidal infiltrating lymphocytes (ITL) survived in SCID mice, but not in nude mice after 8 weeks. The follicles of GD tissue in SCID mice were virtually destroyed with ITL, and their appearance was similar to that in HT. In conclusion, TSH-R Ab was clearly produced from ITL, and some peripheral blood mononuclear cells grafts could also produce TSH-R Ab. In spite of the presence of TSH-R Ab, SCID-TH from GD patients did not show persistent hyperthyroxinemia, presumably because destructive thyroiditis may be occurring in the grafted tissue, with decreasing levels of TSH-R Ab.

Magnetic resonance imaging in preoperative localization of diseased parathyroid glands: a comparison with isotope scanning and ultrasonography

The value of magnetic resonance imaging (MRI) in the preoperative localization of parathyroid glands was assessed through a comparison of the findings with those obtained by ultrasonography and isotope scanning. The localization findings in 37 patients with primary hyperparathyroidism were compared with the operative findings. The sensitivities of the three modalities as defined by the ability to detect a parathyroid adenoma were 67% (isotope scanning), 44% (ultrasonography) and 36% (MRI). The differences were not significant. The sensitivities as defined by the ability to predict the correct side of the lesion were 48% (isotope scanning) 33% (ultrasonography) and 36% (MRI). No correlation was found between the sensitivity of a given localization test and factors such as the presence of thyroid abnormalities, size of the lesion, type of lesion and preoperative calcium and parathormone levels. The low sensitivity and high cost of all three preoperative localization studies render them unnecessary in the management of uncomplicated parathyroid disease. However, if preoperative imaging is necessary, ultrasonography and isotope scanning are recommended, since MRI was not found to be superior.

Efficacy of benzoporphyrin derivative, a photosensitizer, in selective destruction of leukemia cells using a murine tumor model

The ability of a photosensitizer, benzoporphyrin derivative monoacid ring A (BPD), and light to selectively kill leukemic cells in comparison to normal hemopoietic progenitors was investigated using a murine model, the L1210 tumor of DBA/2 mice. In vitro experiments indicated that treatment of cells with BPD and light effected a 5 to 6 log reduction of clonogenic L1210 cells under conditions which caused less than a 1 log reduction of committed myeloid progenitors, determined by colony-forming cells. This apparent therapeutic window was tested in vivo using lethally irradiated DBA/2 mice hematopoietically reconstituted with 10(6) syngeneic donor splenocytes or 5 x 10(5) bone marrow cells mixed with L1210 cells and treated with BPD and light. Reconstitution with 10(6) splenocytes resulted in successful engraftment of approximately 50% of recipients, indicating that these conditions provided limiting numbers of essential stem cells. The minimum tumor-eliciting dose was determined to be between 10(1) and 10(2) L1210 cells. Experiments in which 10(6) splenocytes were mixed with 10(6) L1210 cells and treated with BPD and light demonstrated that at 100 ng/mL of BPD and a specified light dose (5.4 joules [J]/cm2), 50% of recipients underwent successful engraftment and did not develop leukemic ascites. Animals that died under this regimen died from failure to engraft rather than from tumor burden. These results establish that this approach can effectively lower tumor burden by 4 logs with virtually no loss of essential hemopoietic progenitors. Similar results were obtained when animals received bone marrow rather than splenocytes.

Photodynamic elimination of clonogenic Ph+ chronic myeloid leukemia cells

Benzoporphyrin derivative (BPD) and light is a potent photosensitizer. We investigated this modality as a means to selectively eliminate clonogenic Ph(+) chronic myeloid leukemia (CML) cells. BPD at 10 ng/ml and 10.8 J/cm2 broad spectrum light eliminates from 5 to 6 logs of Ph(+) EM-2 cells. Long-term marrow culture studies of treated mixtures of normal and CML cells indicate that multipotent progenitor cell viability is retained while cells transcribing BCR-ABL are not detected. We conclude that BPD and light may offer a means of providing CML autografts potentially free of Ph(+) clonogenic cells.

Reconstitution of severe combined immunodeficient mice with intrathyroidal lymphocytes of thyroid xenografts from patients with Hashimoto's thyroiditis

Thyroid tissues from patients with Hashimoto's thyroiditis (HT) have been xenografted to both severe combined immunodeficiency (SCID) mice and nude mice to study the intrathyroidal lymphocytes which were expected to migrate from the xenografts in the SCID mice. Peripheral blood mononuclear cells from HT, Graves' disease, and normal donors have also been separately engrafted. SCID mice, but not nude mice with HT thyroid grafts produce human immunoglobulins. More immunoglobulin G (IgG), but less IgM and IgA is produced in SCID mice with HT thyroid grafts (SCID-TH), compared to SCID mice injected with peripheral blood mononuclear cells from patients with HT or normal donors (SCID-PB), suggesting that different B cell subpopulations were active in the SCID-PB vs. SCID-TH. Production of IgG by SCID-PB and SCID-TH was maintained 6 weeks after engraftment, and decreased thereafter. SCID mice but not nude mice grafted with HT thyroid tissue produce antibodies to thyroglobulin and thyroperoxidase. Lymphocytes within intact HT thyroid grafts persist in SCID mice, and migrate to the spleen, whereas human lymphocytes do not survive in the thyroid grafts or other tissues of the nude mouse. In 6 weeks, the xenografts in nude mice became histologically normal. In contrast, xenografts from SCID mice showed more marked inflammatory changes than in the original human lesion, although the ratio of T/B cells is unchanged. This worsening of the lesion may relate to the increase in activation of the T-lymphocytes.

Relative sensitivity of leukemic (CML) and normal progenitor cells to treatment with the photosensitizer benzoporphyrin derivative and light

Normal bone marrow and peripheral blood committed progenitor cells were found to be significantly more resistant to treatment with the photosensitizer benzoporphyrin derivative (BPD) and white fluorescent light (11 J/cm2) than were clonogenic cells from two cell lines (K562 and EM2) derived from nonremission patients with myelogenous leukemias. Bone marrow and peripheral blood committed progenitor cells from normal donors were also found to be more resistant to this treatment than were equivalent cells from patients with chronic myelogenous leukemia (CML). Normal bone marrow mononuclear cells grown in long-term marrow culture (LTMC) following treatment with BPD and light showed that no differences in stem cell productivity existed between control and treated samples. When bone marrow from CML patients was treated in the same manner, the numbers of progenitors detected in the nonadherent population during culture were greatly reduced compared to control material. Two rounds of PCR using nested primers to detect BCR-ABL mRNA showed that while this treatment significantly decreased the numbers of stem cells bearing the Philadelphia chromosome, it did not eliminate them.

A T cell nuclear factor resembling NF-AT binds to an NF-kappa B site and to the conserved lymphokine promoter sequence "cytokine-1"

Nuclear extracts from a nontransformed murine T lymphocyte clone contained two inducible factors that bound to a nuclear factor kappa B (NF-kappa B) site. One factor was NF-kappa B, and the other was differentiated from NF-kappa B by its mobility in the electrophoretic mobility shift assay and its lack of sensitivity to protein kinase C depletion. Competition and methylation interference assays showed that the binding site for the novel factor was limited to nucleotides in the 3' half of the kappa B site. This part of the kappa B site resembled sequences in the binding site for a second inducible nuclear factor of T cells, NF-AT, as well as a conserved sequence found in several lymphokine genes, termed "cytokine-1" (CK-1). Competition and methylation interference analysis showed that both NF-AT and CK-1 sequences bound a factor similar to the novel kappa B-binding factor and that binding involved a four-nucleotide sequence (TTCC) that the kappa B, CK-1, and NF-AT sites have in common. The complexes that form with each site have characteristics of NF-AT: they are induced upon T cell receptor stimulation, are sensitive to protein synthesis inhibitors and cyclosporin A, and are not sensitive to protein kinase C depletion. Thus, a factor or factors similar to NF-AT can bind to three distinct promoter sequences which occur commonly in several T cell activation genes. These results raise the possibility that related factors binding to kappa B, CK-1, and NF-AT sequences could play a role in the coordinate induction of T cell activation genes. In addition, our results suggest that kappa B and CK-1 sites represent potential cyclosporin-sensitive promoter elements by virtue of their ability to bind an NF-AT-like factor.

The prognostic importance of site and type of radiation-induced bowel injury in patients requiring surgical management

A multivariate analysis was performed to determine the outcome, and factors prognostic for outcome, in 57 patients requiring surgical intervention for radiation bowel injury. The actuarial 2- and 5-year cause-specific survival (CSS) was 76 and 74%, respectively, with a median follow-up of 62 months for the survivors. The median time from surgery to death from complications was 4 months. Identified sites of injury were both large and small bowel. The types of injury were defined as stricture, perforation, inflammation, and fistula. At surgery 9 patients had more than one site, and 15 patients had more than one type of injury. Cox proportional hazards regression models relating survival to individual patient characteristics were constructed using surgical procedure, radiation-surgery interval, age, stage, radiotherapy technique and dose, and the individual sites and types of injuries. Only the site of injury was found to be of prognostic significance for CSS (P less than 0.03). However, when the site and type of injury were recoded as single or multiple, Cox regression analysis found both the site (P = 0.008) and the type (P = 0.02) of injury to be statistically significant for CSS (favoring single sites and types). Stepwise multivariate regression analysis found type of injury to be insignificant when site of injury was already in the model. Ileal damage was associated with the lowest CSS of any single site of injury (56%) and also appeared to be responsible for the poor CSS of those with multiple sites of injury (46%).

The effect of xenotransplantation of human thyroid tissue following radioactive iodine-induced thyroid ablation on thyroid function in the nude mouse

We have attempted to determine whether xenotransplanted human thyroid tissue into nude mice would act as a physiological substitute for the mouse thyroid gland after the mice had been rendered hypothyroid, using radioactive iodine (131I). The dosage of 0.2 millicuries of 131I was given to each mouse. The xenotransplantations of human thyroid tissue, i.e., normal, Graves' and nontoxic multinodular goitre, were carried out three weeks after radioactive ablation. The values of TSH in all mice rose to high levels (71 +/- 15.6 ng/ml, +/- SD) by three weeks after 131I administration. The TSH values in the mice declined rapidly and reached normal levels by 3-5 weeks after xenotransplantation. In addition, the serum T4 values were generally in the euthyroid range by 3-6 weeks after xenotransplantation. There were no marked differences in the changes of serum T4 and TSH when the three groups were compared. These results indicated that the xenografted human thyroid tissue permitted a return to a normal feedback system as reflected by normal serum TSH and T4 values in the animals. The Graves' thyroid tissue reverted to normal physiological function when removed from its human (abnormal) immune environment, signifying that Graves' thyrocytes are mere passive captives to immune events. This model should prove to be useful in the study of human thyroid physiology and pathophysiology.

Physiologic activation of T cells via the T cell receptor induces NF-kappa B

The transcription factor NF-kappa B has been implicated in the mitogen-induced expression of several genes that are critical for the immunologic function of T cells such as those encoding IL-2 and the IL-2R alpha chain (IL-2R alpha). We show here that NF-kappa B is induced in T cells activated by Ag, anti-CD3 antibody, or allogeneic stimulation. The induction of NF-kappa B via the TCR was dependent on protein kinase C. IL-2, which also activates IL-2R alpha expression and proliferation in T cells, was not able to induce NF-kappa B. TCR-mediated induction of NF-kappa B suggests a central role for this factor in activated T cells and also provides a mechanism for activation of latent HIV provirus during the normal immune response.