Indoximod-based chemo-immunotherapy for pediatric brain tumors: A first-in-children phase I trial

BACKGROUND

Recurrent brain tumors are the leading cause of cancer death in children. Indoleamine 2,3-dioxygenase (IDO) is a targetable metabolic checkpoint that, in preclinical models, inhibits anti-tumor immunity following chemotherapy.

METHODS

We conducted a phase I trial (NCT02502708) of the oral IDO-pathway inhibitor indoximod in children with recurrent brain tumors or newly diagnosed diffuse intrinsic pontine glioma (DIPG). Separate dose-finding arms were performed for indoximod in combination with oral temozolomide (200 mg/m2/day x 5 days in 28-day cycles), or with palliative conformal radiation. Blood samples were collected at baseline and monthly for single-cell RNA-sequencing with paired single-cell T cell receptor sequencing.

RESULTS

Eighty-one patients were treated with indoximod-based combination therapy. Median follow-up was 52 months (range 39-77 months). Maximum tolerated dose was not reached, and the pediatric dose of indoximod was determined as 19.2 mg/kg/dose, twice daily. Median overall survival was 13.3 months (n = 68, range 0.2-62.7) for all patients with recurrent disease and 14.4 months (n = 13, range 4.7-29.7) for DIPG. The subset of n = 26 patients who showed evidence of objective response (even a partial or mixed response) had over 3-fold longer median OS (25.2 months, range 5.4-61.9, p = 0.006) compared to n = 37 nonresponders (7.3 months, range 0.2-62.7). Four patients remain free of active disease longer than 36 months. Single-cell sequencing confirmed emergence of new circulating CD8 T cell clonotypes with late effector phenotype.

CONCLUSIONS

Indoximod was well tolerated and could be safely combined with chemotherapy and radiation. Encouraging preliminary evidence of efficacy supports advancing to Phase II/III trials for pediatric brain tumors.

Inhibition of the BTK-IDO-mTOR axis promotes differentiation of monocyte-lineage dendritic cells and enhances anti-tumor T cell immunity

Monocytic-lineage inflammatory Ly6c+CD103+ dendritic cells (DCs) promote antitumor immunity, but these DCs are infrequent in tumors, even upon chemotherapy. Here, we examined how targeting pathways that inhibit the differentiation of inflammatory myeloid cells affect antitumor immunity. Pharmacologic inhibition of Bruton's tyrosine kinase (BTK) and the tryptophan-degrading enzyme indoleamine 2,3-dioxygenase (IDO) or deletion of Btk or Ido1 allowed robust differentiation of inflammatory Ly6c+CD103+ DCs during chemotherapy, promoting antitumor T cell responses and inhibiting tumor growth. Immature Ly6c+c-kit+ precursor cells had epigenetic profiles similar to conventional DC precursors; deletion of Btk or Ido1 promoted differentiation of these cells. Mechanistically, a BTK-IDO axis inhibited a tryptophan-sensitive differentiation pathway driven by GATOR2 and mTORC1, and disruption of the GATOR2 in monocyte-lineage precursors prevented differentiation into inflammatory DCs in vivo. IDO-expressing DCs and monocytic cells were present across a range of human tumors. Thus, a BTK-IDO axis represses differentiation of inflammatory DCs during chemotherapy, with implications for targeted therapies.

Abstract 2765: The indoleamine 2,3 dioxygenase-1 pathway drives intratumoral B cell maintenance

Immunotherapy has revolutionized cancer treatment by improving survival in many cancer subtypes. While tumor infiltrating B (TIL-B) cells correlate with response to immunotherapy in selected solid tumors, they portend resistance to BRAF inhibitors in BRAF mutant melanoma. Thus, the mechanisms underlying TIL-B cell function within the tumor microenvironment have remained elusive. Here, we discovered that inhibition of the indoleamine 2,3 dioxygenase-1 (IDO1) pathway with D-1-methyl-tryptophan (D-1MT) markedly decreases TIL-B cells in a preclinical model of melanoma. Single cell RNA sequencing (scRNAseq) of murine melanoma demonstrate TIL-B cells are heterogeneous: while some B cells express markers consistent with an immune stimulatory phenotype, others express markers consistent with immune inhibitory function. D-1MT decreased splenic B cells and bone marrow derived B cell precursors in tumor bearing mice, suggesting that IDO1 pathway inhibition impedes B cell maturation. In four distinct human cancer subtypes, intratumoral IDO1 expression consistently correlates with high expression of a pan-B cell gene signature. Further, analysis of scRNAseq data from a cohort of patients with melanoma revealed that most TIL-B cells express IDO1. In mice, D-1MT also decreases intratumoral myeloid derived suppressor cells (MDSCs), which are essential for maintenance of TIL-B cells. Surprisingly, we found that D-1MT enhanced anti-tumor effects of the BRAF inhibitor, vemurafenib, in a preclinical model of BRAF mutant melanoma, suggesting that targeting B cells in this setting may be beneficial. Together, our data reveal a novel paradigm for the IDO1 pathway in regulating TIL-B cells, and uncovered IDO1 as a potential targetable mechanism of resistance to BRAF inhibition in melanoma.

Citation Format: Burles Avner Johnson, Adam K. Aragaki, Donna M. Williams, Ophelia Rogers, Li Luo, Lingling Xian, Lionel Chia, Noah M. Hahn, Stephen Desiderio, Theodore S. Johnson, David J. McConkey, Linda M.S. Resar. The indoleamine 2,3 dioxygenase-1 pathway drives intratumoral B cell maintenance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2765.

IMMU-04. FIRST-IN-CHILDREN PHASE 1B STUDY USING THE IDO PATHWAY INHIBITOR INDOXIMOD IN COMBINATION WITH RADIATION AND CHEMOTHERAPY FOR CHILDREN WITH NEWLY DIAGNOSED DIPG (NCT02502708, NLG2105)

Background

Diffuse intrinsic pontine glioma (DIPG) is a uniformly fatal brain tumor with no available cure. Indoximod blocks the IDO (indoleamine 2,3-dioxygenase) pathway, thereby reversing IDO-mediated immune suppression in the tumor microenvironment.

Methods

Patients aged 3 to 21 years with treatment-naive DIPG were eligible for this phase 1b dose-confirmation study of indoximod. The treatment regimen comprised continuous oral indoximod (38.4 mg/kg/day divided twice daily) with conformal photon radiation (54 Gy in 30 fractions), followed by cycles of indoximod with temozolomide (200 mg/m2/day, days 1–5 in 28-day cycles).

Results

Thirteen patients (median age 9 years, range 5 to 20 years) with DIPG were treated. Median OS was 14.5 months (follow-up ranged 4.8 to 29.3 months), 12-month OS was 61.5% (8/13), and 18-month OS was 30.8% (4/13), with 1 patient remaining in follow-up at the data cutoff. This compared favorably to expected median OS of approximately 10.8 months, 12-month OS of 45.3%, and 18-month OS of 16.2% taken from published historical data from the Pediatric Brain Tumor Consortium. Two patients showed near-complete responses lasting until relapsing after 7.6 months and 13.3 months of study therapy, respectively. Many patients had increased circulating non-classical monocytes (nc-Monos, CD16+, CD14neg, CD33+, HLA-DR+) within the first 3 treatment cycles, and elevation of this early pharmacodynamic marker was predictive of subsequent OS. Patients with nc-Monos >10% (n=7) had median OS of 19 months, whereas patients with nc-Monos below 10% (n=5) had median OS of 7 months (p=0.0047). No patients stopped therapy for toxicity. The most common indoximod-attributed adverse events were thrombocytopenia, neutropenia, nausea, vomiting, dizziness, and fatigue.

Conclusions

Adding indoximod immunotherapy to conventional radiation and chemotherapy for front-line treatment of pediatric patients with DIPG was well-tolerated. Improved outcomes were observed in patients having evidence of pharmacodynamic response. A follow-on phase 2 study is in progress (NCT04049669).

Treg Destabilization and Reprogramming: Implications for Cancer Immunotherapy

Regulatory T cells (Tregs) are an important contributor to the immunosuppressive tumor microenvironment. To date, however, they have been difficult to target for therapy. One emerging new aspect of Treg biology is their apparent functional instability in the face of certain acute proinflammatory signals such as IL6 and IFNγ. Under the right conditions, these signals can cause a rapid loss of suppressor activity and reprogramming of the Tregs into a proinflammatory phenotype. In this review, we propose the hypothesis that this phenotypic modulation does not reflect infidelity to the Treg lineage, but rather represents a natural, physiologic response of Tregs during beneficial inflammation. In tumors, however, this inflammation-induced Treg destabilization is actively opposed by dominant stabilizing factors such as indoleamine 2,3-dioxygenase and the PTEN phosphatase pathway in Tregs. Under such conditions, tumor-associated Tregs remain highly suppressive and inhibit cross-presentation of tumor antigens released by dying tumor cells. Interrupting these Treg stabilizing pathways can render tumor-associated Tregs sensitive to rapid destabilization during immunotherapy, or during the wave of cell death following chemotherapy or radiation, thus enhancing antitumor immune responses. Understanding the emerging pathways of Treg stabilization and destabilization may reveal new molecular targets for therapy. Cancer Res; 78(18); 5191-9. ©2018 AACR.

Activation of p53 in Immature Myeloid Precursor Cells Controls Differentiation into Ly6c+CD103+ Monocytic Antigen-Presenting Cells in Tumors

CD103⁺ dendritic cells are critical for cross-presentation of tumor antigens. Here we have shown that during immunotherapy, large numbers of cells expressing CD103 arose in murine tumors via direct differentiation of Ly6c⁺ monocytic precursors. These Ly6c⁺CD103⁺ cells could derive from bone-marrow monocytic progenitors (cMoPs) or from peripheral cells present within the myeloid-derived suppressor cell (MDSC) population. Differentiation was controlled by inflammation-induced activation of the transcription factor p53, which drove upregulation of Batf3 and acquisition of the Ly6c⁺CD103⁺ phenotype. Mice with a targeted deletion of p53 in myeloid cells selectively lost the Ly6c⁺CD103⁺ population and became unable to respond to multiple forms of immunotherapy and immunogenic chemotherapy. Conversely, increasing p53 expression using a p53-agonist drug caused a sustained increase in Ly6c⁺CD103⁺ cells in tumors during immunotherapy, which markedly enhanced the efficacy and duration of response. Thus, p53-driven differentiation of Ly6c⁺CD103⁺ monocytic cells represents a potent and previously unrecognized target for immunotherapy.

TFE3-positive renal cell carcinoma occurring in three children with dysfunctional kidneys on immunosuppression

Pediatric RCC is a rare pediatric neoplasm and is distinctly different compared to adult RCC, often demonstrating translocation morphology evidenced by unique histopathological features and TFE3 or TFEB nuclear expression. We report three cases of pediatric TFE3 positive RCC (TFE3-RCC) occurring in the setting of chronic kidney disease and long-term pharmacological immunosuppression, including two cases that developed in the native kidney following kidney transplantation. Together, these cases suggest that the kidney microenvironment in combination with immune dysregulation is likely contributing factors in the pathogenesis of some pediatric RCC, warranting further study. Long-term post-transplant surveillance may warrant screening for RCC.

IDO, PTEN-expressing Tregs and control of antigen-presentation in the murine tumor microenvironment

The tumor microenvironment is profoundly immunosuppressive. This creates a major barrier for attempts to combine immunotherapy with conventional chemotherapy or radiation, because the tumor antigens released by these cytotoxic agents are not cross-presented in an immunogenic fashion. In this Focused Research Review, we focus on mouse preclinical studies exploring the role of immunosuppressive Tregs expressing the PTEN lipid phosphatase, and the links between PTEN+ Tregs and the immunoregulatory enzyme indoleamine 2,3-dioxygenase (IDO). IDO has received attention because it can be expressed by a variety of human tumor types in vivo, but IDO can also be induced in host immune cells of both humans and mice in response to inflammation, infection or dying (apoptotic) cells. Mechanistically, IDO and PTEN+ Tregs are closely connected, with IDO causing activation of the PTEN pathway in Tregs. Genetic ablation or pharmacologic inhibition of PTEN in mouse Tregs destabilizes their suppressive phenotype, and this prevents transplantable and autochthonous tumors from creating their normal immunosuppressive microenvironment. Genetic ablation of either IDO or PTEN+ Tregs in mice results in a fundamental defect in the ability to maintain tolerance to antigens associated with apoptotic cells, including dying tumor cells. Consistent with this, pharmacologic inhibitors of either pathway show synergy when combined with cytotoxic agents such as chemotherapy or radiation. Thus, we propose that IDO and PTEN+ Tregs represent closely linked checkpoints that can influence the choice between immune activation versus tolerance to dying tumor cells.

Early career mentoring through the American Society of Pediatric Hematology/Oncology: Lessons learned from a pilot program

BACKGROUND

Effective networking and mentorship are critical determinants of career satisfaction and success in academic medicine. The American Society of Pediatric Hematology/Oncology (ASPHO) mentoring program was developed to support Early Career (EC) members. Herein, the authors report on the initial 2-year outcomes of this novel program.

PROCEDURE

Mentees selected mentors with expertise in different subspecialties within the field from mentor profiles at the ASPHO Web site. Of 23 enrolled pairs, 19 mentors and 16 mentees completed electronic program feedback evaluations. The authors analyzed data collected between February 2013 and December 2014. The authors used descriptive statistics for categorical data and thematic analysis for qualitative data.

RESULTS

The overall response rate was 76% (35/46). At the initiation of the relationship, career development and research planning were the most commonly identified goals for both mentors and mentees. Participants communicated by phone, e-mail, or met in-person at ASPHO annual meetings. Most mentor-mentee pairs were satisfied with the mentoring relationship, considered it a rewarding experience that justified their time and effort, achieved their goals in a timely manner with objective work products, and planned to continue the relationship. However, time constraints and infrequent communications remained a challenge.

CONCLUSIONS

Participation in the ASPHO mentoring program suggests a clear benefit to a broad spectrum of ASPHO EC members with diverse personal and professional development needs. Efforts to expand the mentoring program are ongoing and focused on increasing enrollment of mentors to cover a wider diversity of career tracks/subspecialties and evaluating career and academic outcomes more objectively.

Chemo-Immunotherapy: Role of Indoleamine 2,3-Dioxygenase in Defining Immunogenic Versus Tolerogenic Cell Death in the Tumor Microenvironment

In certain settings, chemotherapy can trigger an immunogenic form of tumor cell death. More often, however, tumor cell death after chemotherapy is not immunogenic, and may be actively tolerizing. However, even in these settings the dying tumor cells may be much more immunogenic than previously recognized, if key suppressive immune checkpoints such as indoleamine 2,3-dioxygenase (IDO) can be blocked. This is an important question, because a robust immune response to dying tumor cells could potentially augment the efficacy of conventional chemotherapy, or enhance the strength and duration of response to other immunologic therapies. Recent findings using preclinical models of self-tolerance and autoimmunity suggest that IDO and related downstream pathways may play a fundamental role in the decision between tolerance versus immune activation in response to dying cells. Thus, in the period of tumor cell death following chemotherapy or immunotherapy, the presence of IDO may help dictate the choice between dominant immunosuppression versus inflammation, antigen cross-presentation, and epitope spreading. The IDO pathway thus differs from other checkpoint-blockade strategies, in that it affects early immune responses, at the level of inflammation, activation of antigen-presenting cells, and initial cross-presentation of tumor antigens. This "up-stream" position may make IDO a potent target for therapeutic inhibition.

The indoleamine 2,3-dioxygenase pathway controls complement-dependent enhancement of chemo-radiation therapy against murine glioblastoma

Background

Indoleamine 2,3-dioxygenase (IDO) is an enzyme with immune-suppressive properties that is commonly exploited by tumors to evade immune destruction. Anti-tumor T cell responses can be initiated in solid tumors, but are immediately suppressed by compensatory upregulation of immunological checkpoints, including IDO. In addition to these known effects on the adaptive immune system, we previously showed widespread, T cell-dependent complement deposition during allogeneic fetal rejection upon maternal treatment with IDO-blockade. We hypothesized that IDO protects glioblastoma from the full effects of chemo-radiation therapy by preventing vascular activation and complement-dependent tumor destruction.

Methods

To test this hypothesis, we utilized a syngeneic orthotopic glioblastoma model in which GL261 glioblastoma tumor cells were stereotactically implanted into the right frontal lobes of syngeneic mice. These mice were treated with IDO-blocking drugs in combination with chemotherapy and radiation therapy.

Results

Pharmacologic inhibition of IDO synergized with chemo-radiation therapy to prolong survival in mice bearing intracranial glioblastoma tumors. We now show that pharmacologic or genetic inhibition of IDO allowed chemo-radiation to trigger widespread complement deposition at sites of tumor growth. Chemotherapy treatment alone resulted in collections of perivascular leukocytes within tumors, but no complement deposition. Adding IDO-blockade led to upregulation of VCAM-1 on vascular endothelium within the tumor microenvironment, and further adding radiation in the presence of IDO-blockade led to widespread deposition of complement. Mice genetically deficient in complement component C3 lost all of the synergistic effects of IDO-blockade on chemo-radiation-induced survival.

Conclusions

Together these findings identify a novel mechanistic link between IDO and complement, and implicate complement as a major downstream effector mechanism for the beneficial effect of IDO-blockade after chemo-radiation therapy. We speculate that this represents a fundamental pathway by which the tumor regulates intratumoral vascular activation and protects itself from immune-mediated tumor destruction.

Etoposide selectively ablates activated T cells to control the immunoregulatory disorder hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is an inborn disorder of immune regulation caused by mutations affecting perforin-dependent cytotoxicity. Defects in this pathway impair negative feedback between cytotoxic lymphocytes and APCs, leading to prolonged and pathologic activation of T cells. Etoposide, a widely used chemotherapeutic drug that inhibits topoisomerase II, is the mainstay of treatment for HLH, although its therapeutic mechanism remains unknown. We used a murine model of HLH, involving lymphocytic choriomeningitis virus infection of perforin-deficient mice, to study the activity and mechanism of etoposide for treating HLH and found that it substantially alleviated all symptoms of murine HLH and allowed prolonged survival. This therapeutic effect was relatively unique among chemotherapeutic agents tested, suggesting distinctive effects on the immune response. We found that the therapeutic mechanism of etoposide in this model system involved potent deletion of activated T cells and efficient suppression of inflammatory cytokine production. This effect was remarkably selective; etoposide did not exert a direct anti-inflammatory effect on macrophages or dendritic cells, and it did not cause deletion of quiescent naive or memory T cells. Finally, etoposide's immunomodulatory effects were similar in wild-type and perforin-deficient animals. Thus, etoposide treats HLH by selectively eliminating pathologic, activated T cells and may have usefulness as a novel immune modulator in a broad array of immunopathologic disorders.

A novel extracellular role for tissue transglutaminase in matrix-bound VEGF-mediated angiogenesis

The importance of tissue transglutaminase (TG2) in angiogenesis is unclear and contradictory. Here we show that inhibition of extracellular TG2 protein crosslinking or downregulation of TG2 expression leads to inhibition of angiogenesis in cell culture, the aorta ring assay and in vivo models. In a human umbilical vein endothelial cell (HUVEC) co-culture model, inhibition of extracellular TG2 activity can halt the progression of angiogenesis, even when introduced after tubule formation has commenced and after addition of excess vascular endothelial growth factor (VEGF). In both cases, this leads to a significant reduction in tubule branching. Knockdown of TG2 by short hairpin (shRNA) results in inhibition of HUVEC migration and tubule formation, which can be restored by add back of wt TG2, but not by the transamidation-defective but GTP-binding mutant W241A. TG2 inhibition results in inhibition of fibronectin deposition in HUVEC monocultures with a parallel reduction in matrix-bound VEGFA, leading to a reduction in phosphorylated VEGF receptor 2 (VEGFR2) at Tyr¹²¹⁴ and its downstream effectors Akt and ERK1/2, and importantly its association with β1 integrin. We propose a mechanism for the involvement of matrix-bound VEGFA in angiogenesis that is dependent on extracellular TG2-related activity.

An inhibitor of thrombin activated fibrinolysis inhibitor (TAFI) can reduce extracellular matrix accumulation in an in vitro model of glucose induced ECM expansion

Chronic kidney disease (CKD) is characterised by the pathological accumulation of extracellular matrix (ECM) proteins leading to progressive kidney scarring via glomerular and tubular basement membrane expansion. Increased ECM synthesis and deposition, coupled with reduced ECM breakdown contribute to the elevated ECM level in CKD. Previous pre-clinical studies have demonstrated that increased plasmin activity has a beneficial effect in the protein overload model of CKD. As plasmin activation is downregulated by the action of the thrombin activated fibrinolytic inhibitor (TAFI), we tested the hypothesis that inhibition of TAFI might increase plasmin activity and reduce ECM accumulation in an in vitro model of glucose induced ECM expansion. Treatment of NRK52E tubular epithelial cells with increasing concentrations of glucose resulted in a 40% increase in TAFI activity, a 38% reduction in plasmin activity and a subsequent increase in ECM accumulation. In this model system, application of the previously reported TAFI inhibitor UK-396082 [(2S)-5-amino-2-[(1-n-propyl-1H-imidazol-4-yl)methyl]pentanoic acid] caused a reduction in TAFI activity, increased plasmin activity and induced a parallel decrease in ECM levels. In contrast, RNAi knockdown of plasmin resulted in an increase in ECM levels. The data presented here indicate that high glucose induces TAFI activity, inhibiting plasmin activation which results in elevated ECM levels in tubular epithelial cells. The results support the hypothesis that UK-396082 is able to reduce TAFI activity, normalising plasmin activity and preventing excess ECM accumulation suggesting that TAFI inhibition may have potential as an anti-scarring strategy in CKD.

Localization of matrix metalloproteinases and their inhibitors in experimental progressive kidney scarring

The extracellular matrix (ECM) is in a continual state of turnover with homeostasis maintained by balancing synthesis and degradation rates. During progressive kidney scarring an imbalance occurs leading to ECM accumulation. Reduced matrix metalloproteinase (MMP) activity is believed to central to this imbalance. However, most of the data relating to MMPs and their natural inhibitors (tissue inhibitors of matrix metalloproteinase (TIMP)) is based on homogenate studies where in situ compartmentalization is lost and thus changes in MMP activity may be artificial. To address this we have developed a sensitive, high-resolution in situ zymography technique and applied it, along with immunohistochemistry, to the 5/6th subtotal nephrectomy model of kidney scarring. ECM proteolytic activity in kidney homogenates progressively declined post-SNx against both gelatin (-82%) and collagen I (-78%) substrates. In situ zymography revealed higher activity with both substrates within the cytoplasm of normal tubular cells compared to the SNx. In contrast, there was 96% greater activity in the SNx glomeruli than normal. Immunohistochemistry confirmed a predominantly intracellular tubular location of all MMPs and TIMPs. Tubules showed reduced MMP-3 and elevated TIMP-2, whereas MMP-1 increased significantly in the glomeruli, especially in the mesangial matrix. TIMP-1 showed a fourfold increase in the remnant kidney by Western blot analysis, but could not be localized. Lowered MMP activity in homogenates results from reduced intracellular activity in the tubules, indicating that reduced MMP activity may not play a direct role in the expansion of the tubular ECM in scarring. However, elevated MMP-1 activity in the glomeruli may play a significant role in initiating glomerular remodelling.

Transglutaminase inhibitors induce hyperproliferation and parakeratosis in tissue-engineered skin

BACKGROUND

The transglutaminase (TG) family consists of eight distinct isoforms. TG types 1, 3 and 5 play a major role in normal skin development, with TG2 also being elevated during dermal wounding. TG1, 3 and 5 are responsible for the cross-linking of keratin precursors and formation of the cornified envelope during keratinocyte differentiation. TG2 may play a role in keratinocyte basement membrane cross-linking. Abnormal TG expression has been demonstrated in Darier disease, Netherton syndrome, psoriasis and lamellar ichthyosis. During a recent investigation of skin contraction in tissue-engineered skin, transglutaminase inhibitors were found to produce hyperproliferation and parakeratosis.

OBJECTIVES

Accordingly, this study was designed to study the effect of pan-transglutaminase inhibition on morphology of tissue-engineered skin and expression of keratinocyte differentiation and proliferation-associated antigens.

METHODS

We used a tissue-engineered model of human skin, based on de-epidermized acellular human dermis, seeded with normal keratinocytes and dermal fibroblasts and cultured at an air-liquid interface. The pan-transglutaminase inhibitors putrescine, NTU283 (1-dimethyl,2-[(oxopropyl)thio]imidazolium) and NTU285 (N-benzyloxycarbonyl-l-glutaminyl-6-dimethylsulfonium-5-oxo-l-norleucine) were added to the culture medium. After 28 days, histology and immunohistochemistry for collagen IV, involucrin and cytokeratins 6, 10 and 16 were performed.

RESULTS

Keratinocyte hyperproliferation and parakeratosis were seen in response to transglutaminase inhibition. Inhibition of transglutaminase also resulted in loss of basement membrane collagen IV. Involucrin and cytokeratins 6 and 16 were confined to the basal layers in control composites but expressed throughout the epidermis in response to transglutaminase inhibition. A distinct band of expression of cytokeratin 10 was seen in the upper stratum granulosum of control composites but only patchy expression was seen after transglutaminase expression.

CONCLUSIONS

Pan-transglutaminase inhibition inhibits terminal differentiation of keratinocytes, leading to a hyperproliferative epidermis with parakeratosis and enhanced expression of involucrin and cytokeratins 6 and 16. Expression of the differentiation-associated cytokeratin, cytokeratin 10, is reduced. Basement membrane integrity is also lost as a result of transglutaminase inhibition.

Sensitivity of finite helical axis parameters to temporally varying realistic motion utilizing an idealized knee model

Various uses of the screw or helical axis have previously been reported in the literature in an attempt to quantify the complex displacements and coupled rotations of in vivo human knee kinematics. Multiple methods have been used by previous authors to calculate the axis parameters, and it has been theorized that the mathematical stability and accuracy of the finite helical axis (FHA) is highly dependent on experimental variability and rotation increment spacing between axis calculations. Previous research has not addressed the sensitivity of the FHA for true in vivo data collection, as required for gait laboratory analysis. This research presents a controlled series of experiments simulating continuous data collection as utilized in gait analysis to investigate the sensitivity of the three-dimensional finite screw axis parameters of rotation, displacement, orientation and location with regard to time step increment spacing, utilizing two different methods for spatial location. Six-degree-of-freedom motion parameters are measured for an idealized rigid body knee model that is constrained to a planar motion profile for the purposes of error analysis. The kinematic data are collected using a multicamera optoelectronic system combined with an error minimization algorithm known as the point cluster method. Rotation about the screw axis is seen to be repeatable, accurate and time step increment insensitive. Displacement along the axis is highly dependent on time step increment sizing, with smaller rotation angles between calculations producing more accuracy. Orientation of the axis in space is accurate with only a slight filtering effect noticed during motion reversal. Locating the screw axis by a projected point onto the screw axis from the mid-point of the finite displacement is found to be less sensitive to motion reversal than finding the intersection of the axis with a reference plane. A filtering effect of the spatial location parameters was noted for larger time step increments during periods of little or no rotation.

Matrix changes induced by transglutaminase 2 lead to inhibition of angiogenesis and tumor growth

Administration of active TG2 to two different in vitro angiogenesis assays resulted in the accumulation of a complex extracellular matrix (ECM) leading to the suppression of endothelial tube formation without causing cell death. Matrix accumulation was accompanied by a decreased rate of ECM turnover, with increased resistance to matrix metalloproteinase-1. Intratumor injection of TG2 into mice bearing CT26 colon carcinoma tumors demonstrated a reduction in tumor growth, and in some cases tumor regression. In TG2 knockout mice, tumor progression was increased and survival rate reduced compared to wild-type mice. In wild-type mice, an increased presence of TG2 was detectable in the host tissue around the tumor. Analysis of CT26 tumors injected with TG2 revealed fibrotic-like tissue containing increased collagen, TG2-mediated crosslink and reduced organized vasculature. TG2-mediated modulation of cell behavior via changes in the ECM may provide a new approach to solid tumor therapy.

Elevated epsilon-(gamma-glutamyl)lysine in human diabetic nephropathy results from increased expression and cellular release of tissue transglutaminase

INTRODUCTION

Diabetic nephropathy (DN) is the leading cause of chronic kidney failure, however the mechanisms underlying the characteristic expansion of the extracellular matrix (ECM) in diabetic kidneys remain controversial and unclear. In non-diabetic kidney scarring the protein crosslinking enzyme tissue transglutaminase (tTg) has been implicated in this process by the formation of increased epsilon-(gamma-glutamyl)lysine bonds between ECM components in both experimental and human disease. Studies in db+/db+ diabetic mice and in streptozotocin-treated rats have suggested a similar mechanism, although the relevance of this to human disease has not been addressed.

METHODS

We have undertaken a retrospective analysis of renal biopsies from 16 DN patients with type 2 diabetes mellitus using an immunohistochemical and immunofluorescence approach, with tTg and epsilon-(gamma-glutamyl)lysine crosslink quantified by confocal microscopy.

RESULTS

Immunofluorescent analysis of human biopsies (confocal microscopy) showed increases in levels of tTg (+1,266%, p < 0.001) and epsilon-(gamma-glutamyl)lysine (+486%, p < 0.001) in kidneys with DN compared to normal. Changes were predominantly in the extracellular periglomerular and peritubular areas. tTg staining correlated with epsilon-(gamma-glutamyl)lysine (r = 0.615, p < 0.01) and renal scarring (Masson's trichrome, r = 0.728, p < 0.001). Significant changes in epsilon-(gamma-glutamyl)lysine were also noted intracellularly in some (< or =5%) tubular epithelial cells. This is consistent with cells undergoing a novel transglutaminase-mediated cell death process in response to Ca2+ influx and subsequent activation of intracellular tTg.

CONCLUSION

Changes in tTg and epsilon-(gamma-glutamyl)lysine occur in human DN. Cellular export of tTg may therefore be a factor in the perpetuation of DN by crosslinking and stabilisation of the ECM, while intracellular activation may lead to cell death contributing towards tubular atrophy.

Potential regulatory function of human dendritic cells expressing indoleamine 2,3-dioxygenase

Antigen-presenting cells (APCs) can induce tolerance or immunity. We describe a subset of human APCs that express indoleamine 2,3-dioxygenase (IDO) and inhibit T cell proliferation in vitro. IDO-positive APCs constituted a discrete subset identified by coexpression of the cell-surface markers CD123 and CCR6. In the dendritic cell (DC) lineage, IDO-mediated suppressor activity was present in fully mature as well as immature CD123+ DCs. IDO+ DCs could also be readily detected in vivo, which suggests that these cells may represent a regulatory subset of APCs in humans.

Caspase-3 and apoptosis in experimental chronic renal scarring

BACKGROUND

Caspase-3 is a member of the caspase enzyme family, having a central role in the execution of apoptosis. However, the significance of Caspase-3 in the inappropriate and excessive apoptosis that contributes to the progression of non-immune-mediated renal scarring has not been established.

METHODS

Kidneys from sham-operated and subtotal nephrectomized (SNx) rats were harvested on days 7, 15, 30, 60, 90 and 120 post-surgery. These were analyzed for apoptosis (in situ end labeling of DNA, light and electron microscopy), Caspase-3 activity (fluorometric substrate cleavage assay), protein and mRNA (Western and Northern blotting), as well as distribution (immunohistochemistry), inflammation (ED-1 immunohistochemistry) and fibrosis (Masson's Trichrome staining).

RESULTS

Apoptosis, inflammation and fibrosis gradually increased in glomeruli, tubules and interstitium of SNx rats. Caspase-3 was mainly located in damaged tubules, but also was found in some glomerular and interstitial cells. Little or no staining was noted in sham-operated kidneys. In SNx kidneys, Caspase-3 activity was significantly increased from day 30 and peaked on day 120 (2.5-fold). This resulted from increases in the 17 and 24 kD active protein subunits. The 32 kD precursor was increased at all time points (1861% on day 120, P < 0.01). Caspase-3 changes were transcription-dependent with the 2.7 kb caspase-3 mRNA significantly increased at all time points (287% on day 120). Caspase-3 activity was a better predictor of apoptosis (Std beta coefficient = 0.347, P < 0.05) than Caspase-3 proteins or mRNA; however, Caspase-3 at all levels correlated with apoptosis, inflammation and fibrosis (all P < 0.01).

CONCLUSIONS

Up-regulation of apoptosis in remnant kidneys is likely to be Caspase-3-dependent as it is associated with increases in Caspase-3 at the activity, protein and mRNA levels. Therefore, Caspase-3 is a potential therapeutic target for the modification of renal cell apoptosis and subsequently renal fibrosis.

Increases in renal epsilon-(gamma-glutamyl)-lysine crosslinks result from compartment-specific changes in tissue transglutaminase in early experimental diabetic nephropathy: pathologic implications

Diabetic nephropathy (DN) is characterized by an early, progressive expansion and sclerosis of the glomerular mesangium leading to glomerulosclerosis. This is associated with parallel fibrosis of the renal interstitium. In experimental renal scarring, the protein cross-linking enzyme, tissue transglutaminase (tTg), is up-regulated and externalized causing an increase in its crosslink product, epsilon-(gamma-glutamyl)-lysine, in the extracellular space. This potentially contributes to the extracellular matrix (ECM) accumulation central to tissue fibrosis by increasing deposition and inhibiting breakdown. We investigated if a similar mechanism may contribute to the ECM expansion characteristic of DN using the rat streptozotocin model over 120 days. Whole kidney epsilon-(gamma-glutamyl)-lysine (HPLC analysis) was significantly increased from Day 90 (+337%) and peaked at Day 120 (+650%) (p < 0.05). Immunofluorescence showed this increase to be predominantly extracellular in the peritubular interstitial space, but also in individual glomeruli. Total kidney transglutaminase (Tg) was not elevated. However, using a Tg in situ activity assay, increased Tg was detected in both the extracellular interstitial space and glomeruli by Day 60, with a maximal 53% increase at Day 120 (p < 0.05). Using a specific anti-tTg antibody, immunohistochemistry showed a similar increase in extracellular enzyme in the interstitium and glomeruli. To biochemically characterize glomerular changes, glomeruli were isolated by selective sieving. In line with whole kidney measurement, there was an increase in glomerular epsilon-(gamma-glutamyl) lysine (+361%); however, in the glomeruli this was associated with increases in Tg activity (+228%) and tTg antigen by Western blotting (+215%). Importantly, the ratio of glomerular epsilon-(gamma-glutamyl) lysine to hydroxyproline increased by 2.2-fold. In DN, changes in the kidney result in increased translocation of tTg to the extracellular environment where high Ca(2+) and low GTP levels allow its activation. In the tubulointerstitium this is independent of increased tTg production, but dependent in the glomerulus. This leads to excessive ECM cross-linking, contributing to the renal fibrosis characteristic of progressive DN.

Differential expression of suppressors of cytokine signalling genes in response to nutrition and growth hormone in the septic rat

GH treatment during critical illness and sepsis may increase mortality. A family of negative regulators of cytokine signalling, the suppressors of cytokine signalling (SOCS), have been characterised. SOCS provide a mechanism for cross-talk between the cytokine receptors, including GH. Here, we have investigated the impact of nutrition and GH treatment on GH receptor, SOCS1, SOCS-2, SOCS-3 and cytokine-inducible SH2-containing protein (CIS) hepatic mRNA expression in a rat model of sepsis, caecal ligation and puncture (CLP). Four groups of rats were studied: control (food given ad libitum, n=7), CLP only (n=8), CLP and total parenteral nutrition (TPN) (n=9), and CLP, TPN and GH (n=10). CLP rats underwent surgery and 18 h later received saline or TPN or TPN+GH for 6 h before they were killed. Serum IGF-I levels were lower in all CLP groups (P<0.001). The combination of TPN and GH treatment increased IGF-I levels compared with the saline-treated CLP rats (P<0.01), but IGF-I levels remained lower than control animals (P<0.001). GH receptor and GH-binding protein expression in liver was reduced in animals subjected to CLP and was unaffected by nutrition or GH treatment. Hepatic SOCS-1 was detectable in normal rats, induced in all CLP animals but was unaffected by nutrition and GH. Hepatic SOCS-2 expression was difficult to detect in normal and CLP rats but was greatly induced in CLP rats treated with GH. Hepatic SOCS-3 expression was only just detectable in the control group but was elevated in all CLP groups and unaffected by nutrition and GH. Hepatic CIS expression was difficult to detect in normal rats, was not induced by CLP but was induced by both nutrition and GH. In conclusion, CLP induced low IGF-I levels associated with increased expression of SOCS-1 and SOCS-3, both of which are known to inhibit GH receptor signalling. GH induced SOCS-2 and CIS in the CLP rat despite resistance with respect to IGF-I generation, and parenteral feeding induced CIS in the CLP rat. Thus, there is potential for a complex interaction between GH and cytokine signalling at the level of SOCS expression whereby the inflammatory response may alter GH signalling and GH may influence the inflammatory response.

A compressed opiate detoxification regime with naltrexone maintenance: patient tolerance, risk assessment and abstinence rates

Opiate detoxification using methadone programmes are inefficient and expensive. Rapid and ultra-rapid detoxification using precipitated withdrawal under heavy sedation or anaesthesia provide increased efficiency and speed, but are limited by the requirement for high-dependency facilities and are perceived as high-risk procedures. Procedures using precipitated withdrawal over longer periods with lower sedation are safer, but 20% of patients fail to tolerate these. Here we evaluate a naltrexone compressed opiate detoxification (NCOD) protocol. We investigated patient acceptance, organ function and abstinence rates on 504 consecutive patients undergoing treatment at the Harrogate Detox5 centre between February 1996 and January 1999. Ninety-eight per cent of patients completed the procedure; 81% of patients reported withdrawal was "better than expected". Only 3% of patients reported any pain. Laboratory investigations demonstrated no organ dysfunction. Abstinence rates post-detox were high with 71%, 61% and 51% of patients free of opiates 3, 6 and 12 months post-detox, respectively. Compliance with the naltrexone maintenance in abstinent patients was 66%, 68% and 30% at these time points. This NCOD protocol provides an efficient method of detoxifying opiate abusers with little patient discomfort or risk to health. Abstinence rates are better than those in comparable studies using other programmes.

Cytokine upregulation of the antigen presenting function of acute myeloid leukemia cells

Acute myeloid leukemia (AML) cells are malignant counterparts of normal myeloid pathway progenitors. Myeloid progenitors differentiate into professional antigen presenting cells (APC) under the essential influence of GM-CSF along with additional cytokines. Twelve cases of human AML were tested for ability to be differentiated toward a professional APC phenotype in short-term culture with addition of GM-CSF and the following recombinant proteins: TNFalpha, IL-4, CD40 ligand, Flt3 ligand and SCF. Significant upregulation of CD80 (B7-1) and enhancement of alloantigen presentation was seen with the addition of GM-CSF and TNFalpha alone or with additional cytokines. The combination of GM-CSF and TNFalpha, either alone or in combination with an additional cytokine, resulted in enhancing alloantigen presentation by at least two-fold over the media control group in 10/12 patients studied, and resulted in CD80 expression of greater than 15% in 11/12 patients studied. In AML cultures with GM-CSF and TNFalpha, coexpression of CD80 and either CD34 or an aberrant surface marker (CD56) was seen. In one case, sorted CD80, cells retained a characteristic cytogenetic marker and CD34 expression, proving their derivation from an AML precursor. These studies verify other reports of in vitro differentiation of human AML precursors into enhanced APC, suggesting that this phenomenon could be utilized for immunotherapy strategies aimed at enhancing presentation of leukemia antigens to T cells.

Transglutaminase transcription and antigen translocation in experimental renal scarring

It was recently demonstrated that renal tissue transglutaminase (tTg) protein and its catalytic product the epsilon(gamma-glutamyl) lysine protein cross-link are significantly increased in the subtotal (5/6) nephrectomy model (SNx) of renal fibrosis in rats. It was proposed that the enzyme had two important physiologic functions in disease development; one of stabilizing the increased extracellular matrix (ECM) by protein cross-linking, the other in a novel form of tubular cell death. This study, using the same rat SNx model, demonstrates first by Northern blotting that expression of tTg mRNA when compared with controls is increased by day 15 (+70% increase, P < 0.05), then rises steadily, peaking at day 90 (+391%, P < 0.01), and remains elevated at 120 d (+205%, P < 0.05) when compared with controls. In situ hybridization histochemistry demonstrated that the tubular cells were the major site of the additional tTg synthesis. Immunohistochemistry on cryostat sections revealed a sixfold increase (P < 0.001) in ECM-bound tTg antigen at 90-d post-SNx, whereas in situ transglutaminase activity demonstrated by the incorporation of fluorescein cadaverine into cryostat sections indicated a 750% increase (P < 0.001) on day 90 in SNx animals. This increased activity was extracellular and predominantly found in the peritubular region. These results indicate that increased tTg gene transcription by tubular cells underlies the major changes in renal tTg protein reported previously in SNx rats, and that the presence of the epsilon(gamma-glutamyl) lysine cross-links in the extracellular environment is the result of the extracellular action of tTg. These changes may be in response to tubular cell injury during the scarring process and are likely to contribute to the progressive expansion of the ECM in renal fibrosis.

Effects of transforming growth factor-beta1 on renal extracellular matrix components and their regulating proteins

Transforming growth factor-beta1 (TGF-beta1) is widely regarded as a potent fibrogenic renal growth factor. In cell culture, TGF-beta1 has been shown to increase various extracellular matrix (ECM) proteins and tissue inhibitors of metalloproteinases (TIMP), while decreasing matrix metalloproteinases (MMP), providing the optimum environment for progressive ECM accumulation. This study, which uses the isolated perfused rat kidney (IPRK), describes for the first time in a whole kidney preparation the action of TGF-beta1 on factors associated with ECM processing. This model allows the study of the intact rat kidney with physiologic cell-cell interactions in the absence of confounding systemic influences. Left kidneys were removed from male Wistar rats by a nonischemic technique and perfused with a sterile, apyrogenic, endotoxin-free perfusate, based on the plasma volume expander Hemaccel (polygeline), at constant pressure in a recirculating IPRK system. Kidneys were perfused for 1 h either with (n = 3) or without (n = 3) recombinant human TGF-beta1 (20 ng/ml). The effects of perfusion were controlled by comparison with the nonperfused contralateral kidney (n = 6). TGF-beta1 was measured in the perfusate and urine, at the start and end of the experiment using an enzyme-linked immunosorbent assay to its biologically active form. After perfusion, sections of the kidneys were analyzed for changes in mRNA by Northern blotting. Significant increases in mRNA for fibronectin (7.5-fold, P < 0.01), heparan sulfate proteoglycan core protein (53-fold, P < 0.001), laminin beta1 (12-fold, P < 0.001), collagen alpha1(IV) (17-fold, P < 0.001), collagen alpha1(III) (fourfold, P < 0.001), and MMP9 (twofold, P < 0.05) were observed after perfusion with TGF-beta1. Measurement of TIMP1, TIMP2, TIMP3, MMP1, and MMP2 mRNA demonstrated no detectable change, whereas determination of mRNA for tissue transglutaminase, an enzyme capable of cross-linking many ECM components, showed an eightfold increase (P < 0.01). This study suggests that in the IPRK and in the absence of other exogenous growth factors, TGF-beta1 selectively increases the synthesis of ECM and tissue transglutaminase without changes that would result in the reduction of ECM degradation.

A home visit program for breastfeeding education and support

A home visit program for breastfeeding education and intervention was developed to provide support for mothers and infants at risk for breastfeeding failure. This program was developed to supplement the Early Discharge Program for mothers and newborns who were discharged within 24 hours of delivery. A breastfeeding assessment tool was developed for use in the hospital and during the early discharge home visit. Home visits are provided by a registered nurse with mother-infant assessment skills and competence to provide breastfeeding education, problem management, emotional support, and referrals to lactation consultants or physicians as needed. The response from patients and physicians has been positive. As the demand for services grew, the program was modified to include other mothers and infants (e.g., those delivering via cesarean and high-risk, preterm, and borderline preterm infants in need of breastfeeding support). The readmission rate for breastfeeding infants who receive a home visit is lower than for infants who do not receive a home visit. Patient satisfaction surveys have been positive.

Reliability of three length measurement techniques in term infants

PURPOSE

To describe and compare the intra- and interexaminer reliability of three length measurement techniques and to determine if the three measurement techniques yield significantly different measurements.

METHOD

Two experienced, mother-baby nurses each obtained length measurements using the supine, paper barrier, and Auto-length measurement techniques twice each from 48 healthy term infants. The nurses were blind to their own and to each other's measurements. The order of the nurses and the order of the measurement techniques were randomized.

RESULTS

For intraexaminer reliability, RN-1 had smaller mean absolute differences for the Auto-length measurements. RN-2 had similar mean absolute differences for all three measurement techniques. The percentage of differences < or = 1 cm were smallest for the supine measurements for RN-1 and not remarkably different between the measurement techniques for RN-2. For interexaminer reliability, the mean absolute differences between the pairs of measurements were smallest for the Auto-length measurements for Set-1 and for the paper-barrier measurements for Set-2. The percentage of differences < or = 1 cm between the pairs of measurements for Set-1 were not remarkably different and were lowest for the supine measurements for Set-2. The mean measurements obtained by the supine, paper-barrier, and the Auto-length measurements were respectively: 50.88, 50.33, and 49.67 cm. The differences between the means were statistically significant (X2 = 56.56, p = .0000).

CONCLUSIONS

The differences between length measurements by individual examiners and pairs of examiners are relatively large. Clinicians should be aware of the magnitude of error in length measurements and should interpret length measurements with caution. These findings also demonstrate that all clinicians in any setting should use the same technique to obtain length measurements.

Reliability of length measurements in full-term neonates

OBJECTIVE

To describe and compare the intra- and interexaminer reliability of four techniques for measuring length in full-term newborns and to determine whether the different techniques yield significantly different measurements.

DESIGN

A descriptive study, describing the intra- and interexaminer reliability of four length measurement techniques: crown-heel, supine, paper barrier, and Neo-infantometer. The nurses were blind to their own and to the other nurse's measurements. The order of the nurses and the order in which the measurements were obtained was randomized.

SETTING

Mothers' rooms in a university hospital.

PARTICIPANTS

Thirty-two healthy full-term newborns.

INTERVENTIONS

Length measurements using four different length techniques were obtained twice each by two experienced neonatal nurses.

MAIN OUTCOME MEASURES

To measure the intra- and interexaminer reliability, the following statistics were calculated: mean absolute differences, standard deviations, technical error of measurement; percentage less than .5 and 1.0 cm, and percentage of error.

RESULTS

Intra- and interexaminer differences were significantly larger when examiners used the crown-heel measurement technique. Although the intra- and interexaminer reliability of length measurements obtained with the supine, paper barrier, and Neo-infantometer techniques did not differ significantly, the amount of error in these measurements was large.

CONCLUSIONS

Measurements obtained using the crown-heel technique are significantly less reliable than measurements obtained using the supine, paper barrier, or Neo-infantometer techniques.

Induction of tissue transglutaminase by dexamethasone: its correlation to receptor number and transglutaminase-mediated cell death in a series of malignant hamster fibrosarcomas

Treatment of the hamster fibrosarcoma cell lines (Met B, D and E) and BHK-21 hamster fibroblast cells with the glucocorticoid dexamethasone led to a powerful dose-dependent mRNA-synthesis-dependent increase in transglutaminase activity, which can be correlated with dexamethasone-responsive receptor numbers in each cell line. Increasing the number of dexamethasone-responsive receptors by transfection of cells with the HG1 glucocorticoid receptor protein caused an increase in transglutaminase activity that was proportional to the level of transfected receptor. In all experiments the levels of the tissue transglutaminase-mediated detergent-insoluble bodies was found to be comparable with increases in transglutaminase activity. Despite an increase in detergent-insoluble body formation, an increase in apoptosis as measured by DNA fragmentation was not found. Incubation of cells with the non-toxic competitive transglutaminase substrate fluorescein cadaverine led to the incorporation of this fluorescent amine into cellular proteins when cells were damaged after exposure to trypsin during cell passage. These cross-linked proteins containing fluorescein cadaverine were shown to be present in the detergent-insoluble bodies, indicating that the origin of these bodies is via activation of tissue transglutaminase after cell damage by trypsinization rather than apoptosis per se, since Met B cells expressing the bcl-2 cDNA were not protected from detergent-insoluble body formation. We describe a novel mechanism of cell death related to tissue transglutaminase expression and cell damage.

Reliability of head circumference measurements in preterm infants

PURPOSE

To describe and compare the intra- and interexaminer reliability of head circumference measurements obtained with paper and cloth tape measures.

METHOD

Two experienced neonatal nurses each obtained head circumference measurements using both paper and cloth tape measures twice each, from 49 clinically stable, preterm infants. The nurses were blind to their own and to each other's measurements. The order in which the measurements were obtained was randomized. The differences within and between examiners for cloth and paper tape measurements were described using mean absolute differences, standard deviation of net differences, technical error of measurement, minimal and maximal differences, percentage of differences 0.25 and 0.5 cm, and percentage of error.

RESULTS

Wilcoxon matched-pairs, signed-ranks tests demonstrated significantly greater intraexaminer reliability for measurements obtained with the paper tape for both of the nurses. Wilcoxon matched-pairs, signed-ranks tests also demonstrated significantly greater interexaminer reliability for measurements obtained with the paper tape for both the first and second measurement sets.

CONCLUSIONS

Intra- and interexaminer differences were consistently smaller when the examiners used paper tape measures.

The role of transglutaminase in the rat subtotal nephrectomy model of renal fibrosis

Tissue transglutaminase is a calcium-dependent enzyme that catalyzes the cross-linking of polypeptide chains, including those of extracellular matrix (ECM) proteins, through the formation of epsilon-(gamma-glutamyl) lysine bonds. This crosslinking leads to the formation of protein polymers that are highly resistant to degradation. As a consequence, the enzyme has been implicated in the deposition of ECM protein in fibrotic diseases such as pulmonary fibrosis and atherosclerosis. In this study, we have investigated the involvement of tissue transglutaminase in the development of kidney fibrosis in adult male Wistar rats submitted to subtotal nephrectomy (SNx). Groups of six rats were killed on days 7, 30, 90, and 120 after SNx. As previously described, these rats developed progressive glomerulosclerosis and tubulo-interstitial fibrosis. The tissue level of epsilon-(gamma-glutamyl) lysine cross-link (as determined by exhaustive proteolytic digestion followed by cation exchange chromatography) increased from 3.47+/- 0.94 (mean+/-SEM) in controls to 13.24+/-1.43 nmol/g protein 90 d after SNx, P </= 0.01. Levels of epsilon-(gamma-glutamyl) lysine cross-link correlated well with the renal fibrosis score throughout the 120 observation days (r = 0.78, P </= 0.01). Tissue homogenates showed no significant change in overall transglutaminase activity (14C putrescine incorporation assay) unless adjusted for the loss of viable tubule cells, when an increase from 5.77+/-0.35 to 13.93+/-4.21 U/mg DNA in cytosolic tissue transglutaminase activity was seen. This increase was supported by Western blot analysis, showing a parallel increase in renal tissue transglutaminase content. Immunohistochemistry demonstrated that this large increase in epsilon-(gamma-glutamyl) lysine cross-link and tissue transglutaminase took place predominantly in the cytoplasm of tubular cells, while immunofluorescence also showed low levels of the epsilon-(gamma-glutamyl) lysine cross-link in the extracellular renal interstitial space. The number of cells showing increases in tissue transglutaminase and its cross-link product, epsilon-(gamma-glutamyl) lysine appeared greater than those showing signs of typical apoptosis as determined by in situ end-labeling. This observed association between tissue transglutaminase, epsilon-(gamma-glutamyl) lysine cross-link, and renal tubulointerstitial scarring in rats submitted to SNx suggests that tissue transglutaminase may play an important role in the development of experimental renal fibrosis and the associated loss of tubule integrity.

Intra- and interexaminer reliability of anthropometric measurements of term infants

BACKGROUND

The reliability of anthropometric measurements of term infants has not been studied sufficiently to determine if these measurements are reliable enough to be used in clinical practice and research. This study described the intra- and interexaminer reliability of the following anthropometric measurements: weight (WT), head circumference (HC), chest circumference (CC), abdominal circumference (AC), mid-arm circumference (MAC), and length.

METHODS

A convenience sample of 50 clinically stable term infants was studied. Two examiners obtained the six measurements twice using blank tape measures. The order of examiners was randomized and the examiners were masked to their own and the other examiners' measurements.

RESULTS

The intraexaminer mean absolute differences were as follows: WT = 1.88, 3.28 g; HC = 0.29, 0.29 cm; CC = 0.50, 0.78 cm; AC = 0.71, 0.77 cm; MAC = 0.36, 0.39 cm; length = 0.92, 1.18 cm. The interexaminer mean absolute differences were as follows: WT = 1.94, 1.66 g; HC = 0.37, 0.36 cm; CC = 0.59, 0.72 cm; AC = 0.99, 0.77 cm; MAC = 0.41, 0.57 cm; length = 1.57, 1.47 cm.

CONCLUSIONS

These findings indicate that intraexaminer differences tended to be smaller than interexaminer differences for all measures except weight, which remained stable for intra- and interexaminer comparisons. These findings also suggest that weight and head circumference were the most reliable measures, whereas length and mid-arm circumference were the least reliable measures.

Enhanced cell proliferation and biosynthesis mediate improved wound repair in refed, caloric-restricted mice

Aged mice that have undergone long-term caloric-restriction (CR) have improved health and enhanced longevity in comparison to aged mice that are ad libitum-fed (AL). However, caloric-restriction does not benefit the impaired wound healing of aged mice. To test the hypothesis that CR mice have the capacity for enhanced wound repair, but require a short-term period of additional nutrient intake to show this advantage, we assessed wound healing in CR mice that had been refed (RF) an ad libitum diet for 4 weeks prior to wounding. Two strains of AL young (Y AL) (4-6 months), AL middle-aged (M AL) (15-17 months), and three different, matched cohorts of old mice (O) (30-33 months): O AL, O CR, and O RF were studied. Two full-thickness 4 mm diameter punch biopsy skin wounds were created on the dorsum of each mouse. Animals were sacrificed and wounds were harvested at 1,2,3,5, and 7 days post-wounding. Repair of wounds was slower in O AL and O CR mice compared to Y AL and M AL animals. In contrast, the O RF mice healed similarly to that of the Y AL and M AL mice, as assessed by measures of wound area and histologic criteria. O RF mice demonstrated enhanced synthesis of type I collagen mRNA in comparison to O AL and O CR mice. A greater number of endothelial cells and fibroblasts at the wound edge of the O RF mice exhibited replication in vivo as measured by uptake of BrdU. O RF mice had higher levels of insulin-like binding protein 3 (IGFBP-3). Furthermore, fibroblasts derived from the explant of the punch biopsy of O CR mouse skin revealed enhanced proliferation and contraction in vitro, in comparison to fibroblasts from the O AL mice. In conclusion, O RF mice demonstrate an enhanced capacity to undergo wound repair in comparison to O AL mice. This effect appears to be mediated, in part, by enhanced cell proliferation, contraction, and collagen biosynthesis. In addition, short-term refeeding induced an increase in the serum level of IGFBP-3, the major binding protein for IGF-1. These data confirm that cells from O CR animals have a preserved proliferative, biosynthetic, and contractile capacity, but that an adequate source of nutrients is necessary to demonstrate this advantage in wound healing.

Cyclosporine enhances the expression of TGF-beta in the juxtaglomerular cells of the rat kidney

The mediators of cyclosporine (CsA) nephrotoxicity remain ill defined. In this study, we describe evidence of increased amounts of transforming growth factor-beta (TGF-beta) in the kidneys of adult male Wistar rats treated with CsA (5 to 25 mg/kg/day) for four weeks. Localization of TGF-beta was undertaken immunocytochemically at both light and electron microscope levels and Northern blot analysis was applied to detect changes in transcription of TGF-beta. In control rats, weak to moderate immunostaining for TGF-beta was observed, in the juxtaglomerular arterioles. CsA treatment resulted in a dose-dependent increase in the number of stained afferent and interlobular arterioles and in the intensity of staining. The number of stained afferent arterioles increased from a control value of 0.21 +/- 0.08/mm2 cortex to 0.84 +/- 0.15/mm2 cortex, P < 0.01, and to 1.12 +/- 0.10/mm2 cortex, P < 0.01, in rats treated with CsA 12.5 mg/kg/day and 25 mg/kg/day, respectively. The number of interlobular arterioles stained for TGF-beta increased from a control value of 0.07 +/- 0.05/mm2 to 0.31 +/- 0.02/mm2, P < 0.05, and 0.39 +/- 0.07/mm2, P < 0.01, in rats treated with CsA, 12.5 mg/kg/day and 25 mg/kg/day, respectively. At the electron microscope level, TGF-beta was localized exclusively within the granular cells of the juxtaglomerular arterioles. Northern blot analysis suggested that this enhanced staining is due to increased transcription of TGF-beta 1. We have therefore observed an association between TGF-beta and CsA-induced nephrotoxicity. While this does not establish a causal link, it leads us to postulate that TGF-beta, alone or in combination with other growth factors, may play a role in the pathogenesis of CsA induced nephrotoxicity.

Transfection of tissue transglutaminase into a highly malignant hamster fibrosarcoma leads to a reduced incidence of primary tumour growth

Reduced expression of the tissue transglutaminase in both murine and human tumours has been consistently associated with tumour growth and progression. To investigate the functional effects of transglutaminase expression we have transfected a constitutive human tissue transglutaminase expression construct into a highly malignant hamster fibrosarcoma cell line Met B. Met B clones expressing the exogenous tissue transglutaminase exhibited a reduced incidence of primary tumour formation and an increased adherence to tissue culture plastic and fibronectin coated surfaces when compared to transfected and non transfected control cells. Transglutaminase transfected clones exhibited no significant differences in their growth rates measured in vitro, cell morphology or levels of spontaneous apoptosis measured by the determination of detergent insoluble apoptotic envelopes. The data demonstrates a suppressive effect of tissue transglutaminase on tumour growth and confirms its importance in the phenotypic changes associated with the cancer process.

Flow-cytochemical differential leukocyte analysis with quantitation of neutrophil left shift. An evaluation of the Cobas-Helios analyzer

The Cobas-Helios (Roche Diagnostic Systems, Inc., Branchburg, NJ) is a new, fully automated hematology analyzer that performs a complete blood count and differential leukocyte count (DLC), classifying leukocytes by flow-cytochemical technology. The DLC component of the Cobas-Helios was evaluated according to the National Committee for Clinical Laboratory Standards H20-A protocol. Instrument performance was acceptable with respect to all parameters investigated, including imprecision, inaccuracy and clinical sensitivity for the identification of quantitative and qualitative leukocyte abnormalities. In a minority of samples with neutrophil left shift, neutrophils tended to overlap the monocyte domain, resulting in overestimation of monocytes and underestimation of neutrophils. This problem did not affect clinical sensitivity and was generally associated with a positive instrumental left-shift flag. Flags for the identification of specific qualitative abnormalities of the leukocyte population (atypical lymphoid cells, nucleated red cells, blast cells, immature granulocytes and neutrophil left shift) performed well. In addition to a conventional five-part DLC, the Cobas-Helios also identifies and quantitates atypical lymphoid cells and "large immature cells," the latter corresponding to bands and immature granulocytes. Counts of atypical lymphoid cells and large immature cells correlated well with the equivalent cell classes as enumerated by the reference method of the National Committee for Clinical Laboratory Standards. The Cobas-Helios offers the most reliable quantitative index of neutrophil left shift currently available in a commercial automated DLC analyzer.

HLA class II-restricted binding of muramyl peptides to B lymphocytes of normal and narcoleptic subjects

The propensity for narcolepsy, a clinical sleep disorder of unknown etiology, is virtually totally included within the HLA-DR2,DQw1 (DRw15,DQw6) phenotype. The disorder is characterized by decreased sleep latency, early onset of rapid eye movement sleep, and a paucity of nocturnal slow-wave sleep. Muramyl peptides, naturally occurring bacterial cell wall peptidoglycans, potently enhance the duration and amplitude of slow-wave sleep in animals, bind to murine mononuclear cells, and exhibit a major histocompatibility complex-restricted immunoadjuvant effect in mice. We examined the binding of muramyl peptides to peripheral blood mononuclear leukocytes of HLA-typed normal (n = 13) and narcoleptic (n = 10) subjects. Muramyl peptides bound specifically and with high affinity to normal B- but not T-lymphocyte-enriched preparations. There was no significant specific binding to B-cell-enriched preparations from narcoleptic patients. Furthermore, B-lymphocyte-enriched preparations of normal individuals who had the HLA-DR2,DQw1 phenotype (n = 8) exhibited a lower level of specific binding than those of normals who did not have this phenotype (n = 5, p less than 0.001). These observations are an additional indication of the relevance of muramyl peptides to slow-wave sleep and provide a basis for a better understanding of the relation between narcolepsy and the MHC at the biochemical level.