Publications by authors named "Sandker G"

Introduction: Combined radiotherapy and immune checkpoint inhibition is a potential treatment option for head and neck squamous cell carcinoma (HNSCC). Immunocompetent mouse models can help to successfully develop radio- immunotherapy combinations and to increase our understanding of the effects of radiotherapy on the tumor microenvironment for future clinical translation. Therefore, the aim of this study was to develop a homogeneous, reproducible HNSCC model originating from the Mouse Oral Cancer 1 (MOC1) HNSCC cell line, and to explore the radiotherapy-induced changes in its tumor microenvironment, using flow cytometry and PD-L1 microSPECT/CT imaging.

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CD3 bispecific antibody (CD3 bsAb) therapy is clinically approved for refractory hematological malignancies, but responses in solid tumors have been limited so far. One of the main hurdles in solid tumors is the lack of sufficient T-cell infiltrate. Here, we show that pre-treatment vaccination, even when composed of tumor-unrelated antigens, induces CXCR3-mediated T-cell influx in immunologically 'cold' tumor models in male mice.

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Background: CD3 bispecific antibodies (CD3-bsAbs) require binding of both a tumor-associated surface antigen and CD3 for their immunotherapeutic effect. Their efficacy is, therefore, influenced by the tumor uptake and the extracellular dose. To optimize their currently limited efficacy in solid tumors, increased understanding of their pharmacokinetics and in vivo internalization is needed.

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Background: Programmed death-ligand 1 (PD-L1) regulates immune homeostasis by promoting T-cell exhaustion. It is involved in chronic infections and tumor progression. Nuclear imaging using radiolabeled anti-PD-L1 antibodies can monitor PD-L1 tissue expression and antibody distribution.

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With the advent of novel immunotherapies, interest in ex vivo autologous cell labeling for in vivo cell tracking has revived. However, current clinically available labeling strategies have several drawbacks, such as release of radiolabel over time and cytotoxicity. Poly(lactic--glycolic acid) nanoparticles (PLGA NPs) are clinically used biodegradable carriers of contrast agents, with high loading capacity for multimodal imaging agents.

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Article Synopsis
  • GLP-1R imaging using radiolabeled exendin is an effective method for measuring β-cell mass (BCM) in living organisms.
  • High blood glucose levels lead to reduced exendin uptake in both mouse and human islets, correlating with decreased GLP-1R expression.
  • Normalizing blood glucose levels can restore exendin uptake and GLP-1R expression, highlighting the importance of stable glycemic control before starting GLP-1R treatments or BCM assessments.
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Article Synopsis
  • Treatment of hyperinsulinemic hypoglycemia poses challenges, as current surgical and medication options are invasive and can cause serious side effects.
  • A novel therapy called receptor-targeted photodynamic therapy (rtPDT) uses exendin-4-IRDye700DX to selectively target and kill β-cells by binding to the glucagon-like peptide 1 receptor (GLP-1R).
  • In studies, rtPDT demonstrated significant effectiveness in reducing cell viability in GLP-1R-positive cells and showed promise in extending survival in mice, suggesting a potential new treatment for this condition that is both effective and minimally invasive.
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The treatment of choice for insulinomas and focal lesions in congenital hyperinsulinism (CHI) is surgery. However, intraoperative detection can be challenging. This challenge could be overcome with intraoperative fluorescence imaging, which provides real-time lesion detection with a high spatial resolution.

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Immunotherapy with checkpoint inhibitors demonstrates impressive improvements in the treatment of several types of cancer. Unfortunately, not all patients respond to therapy while severe immune-related adverse effects are prevalent. Currently, patient stratification is based on immunotherapy marker expression through immunohistochemical analysis on biopsied material.

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Purpose: Currently, the most commonly used chelator for labelling antibodies with Zr for immunoPET is desferrioxamine B (DFO). However, preclinical studies have shown that the limited in vivo stability of the Zr-DFO complex results in release of Zr, which accumulates in mineral bone. Here we report a novel chelator DFOcyclo*, a preorganized extended DFO derivative that enables octacoordination of the Zr radiometal.

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Antibodies that block the interaction between programmed death ligand 1 (PD-L1) and PD-1 have shown impressive responses in subgroups of patients with cancer. PD-L1 expression in tumors seems to be a prerequisite for treatment response. However, PD-L1 is heterogeneously expressed within tumor lesions and may change upon disease progression and treatment.

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Background: The aim of the study was to assess the use of the Nijmegen Clinical Screening Instrument (NCSI) and Short Form 36 (SF-36) in providing a detailed assessment of health status of Q-fever patients and to evaluate which subdomains within the NCSI and SF-36 measure unique aspects of health status.

Findings: Patients received a study questionnaire, which contained the NCSI and SF-36. Pearson correlation coefficients between subdomains of the instruments were calculated.

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The aim of this study was to compare human hepatocytes isolated from livers accepted and from livers discarded for transplantation with respect to viability and drug transport function. In addition, the influence of age of the donor and preservation time of the liver on cell viability was determined. Cell viability was assessed by trypan blue exclusion, MTT reduction, morphological integrity and ATP content, and drug transport function by uptake and excretion of taurocholic acid.

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The uptake and efflux of three categories of substrates were measured in isolated human hepatocytes and compared to those in rat hepatocytes. In addition, the extent to which the in vitro experiments quantitatively reflect liver function in vivo in both species was investigated. The anionic bile acid taurocholic acid was taken up by isolated human hepatocytes at a considerably lower rate than observed in isolated rat hepatocytes.

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1. The metabolism of the three drugs (Org GB 94, Org 3770 and Org OD 14) was studied in isolated human and rat hepatocytes. The metabolic profiles in rat and human hepatocytes were compared with the available in vivo data in both species.

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Rat hepatocytes were preserved for 24 hr with high recovery and good maintenance of viability and transport function both in University of Wisconsin (UW) solution and in various simplified UW solutions. Cell quality is somewhat affected after 48 hr of preservation in both the original UW solution and the simplified solutions. ATP content and uptake rate of taurocholic acid are more sensitive markers of cell viability than Trypan blue exclusion or the MTT test.

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This study describes dietary fatty acid intake, as assessed from serum cholesteryl ester composition, and its relation to serum lipoprotein levels in 100 age-matched elderly men from Crete and Zutphen. All were survivors of the respective cohorts of the Seven Countries Study [Keys A (1980) Seven countries: a multivariate analysis of death and coronary heart disease. Cambridge, MA: Harvard University Press].

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Isolated hepatocytes are a valuable tool to study liver functions. Suitable methods to preserve the isolated cells with good maintenance of viability and functions are crucial to extend experiments with hepatocytes from a single isolation over 2 or more consecutive days. We investigated whether University of Wisconsin (UW) solution, which was designed to preserve organs for transplantation, is also suitable for preservation of isolated rat hepatocytes.

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The inducing capability of the synthetic flavonol beta-naphthoflavone (beta-NF) on cytochrome P-450 content was studied in primary chick embryo hepatocytes. In addition, the modulating effects of pretreatment with beta-NF on the induction of sister-chromatid exchanges (SCEs) in V79 cells by mutagens from different chemical classes were investigated in a co-cultivation system consisting of primary chick embryo hepatocytes and V79 Chinese hamster cells. Finally, the effects of pretreatment on benzo[a]pyrene (B(a)P) metabolism were studied in more detail.

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