Mathematical modeling of the glucose-insulin system during peritoneal dialysis with glucose-based fluids

The purpose of this study was to analyze the effect of peritoneal dialysis with glucose-based solution on plasma glucose and insulin responses in patients on continuous ambulatory peritoneal dialysis (CAPD), describe the glucose-insulin system using a mathematical model, and identify abnormalities in this system. Six-hour dwell studies--using glucose 3.86% solution with a volume marker--were performed in 13 stable, fasting, nondiabetic CAPD patients. We used a mathematical model based on the previous works of Stolwijk and Hardy (1974) and Tolic et al (2000) to estimate the parameters of glucose-insulin system, insulin sensitivity index (Sl), and glucose effectiveness at basal (SG) and zero (GEZI) insulin. The individual peaks in plasma glucose and insulin concentrations occurred after 30-60 minutes of the dwell, with the average increase of 52% and 168% over the initial values, respectively. Increased insulin resistance was found in most of these patients. Both clinical and simulation results demonstrated a high interpatient variability in glucose and insulin kinetics and glucose-insulin system parameters in the patients. We demonstrated a successful control of increasing plasma glucose by insulin, despite an increased insulin resistance, during CAPD.     

Micropapillary carcinoma of the parotid gland arising in mucinous cystadenoma

We describe a 45-year-old man who had a 2-year history of a slowly enlarging tumor in the left parotid gland. Histologically, the tumor was a mucinous cystadenoma with focal apocrine differentiation, which revealed a widespread invasive micropapillary adenocarcinoma component. A rim of lymphoid tissue surrounded the margins of the micropapillary carcinoma. The invasive micropapillary adenocarcinoma component was morphologically identical with the invasive micropapillary carcinoma of the mammary gland. The tumor is different from so-far recognized salivary gland tumor entities. Received: 25 October 1999 / Accepted: 13 June 2000     

Cribriform adenocarcinoma of the tongue

We report a case of a 73-year-old female with a tumour of the tongue, operated with two relapses. A single metastasis to the lymph node was present. Currently, the patient is alive without evidence of disease. The histological diagnosis of cribriform adenocarcinoma of the tongue was rendered. The differential diagnosis of adenocarcinomas of the tongue is discussed.     

In vivo and in vitro characterization of [18F]-FE-(+)-DTBZ as a tracer for beta-cell mass

IntroductionThe positron emission tomography (PET) tracer 9-[¹⁸F]fluoroethyl-(+)-dihydrotetrabenazine ([¹⁸F]-FE-(+)-DTBZ) is a potential candidate for quantifying beta-cell mass in vivo. The purpose was to investigate in vitro and in vivo utility of this tracer for the assessment of beta-cell mass.MethodsThree pigs were intravenously administered [¹⁸F]-FE-(+)-DTBZ and examined by PET/computed tomography. Binding parameters were estimated by kinetic modeling. In vitro k_D and B_max were determined by saturation binding studies of endocrine and exocrine human tissue homogenates. In vitro pancreatic uptake was determined by tissue autoradiography with pancreases from patients with types 1 (T1DM) and 2 diabetes mellitus (T2DM) and healthy controls.Results[¹⁸F]-FE-(+)-DTBZ had a k_D of 3.5±1.0 nM, a B_max of 382±108 fmol/mg protein and a specificity of 89±1.8% in islet homogenates. The total exocrine uptake was lower and 65% was nondisplaceable. No uptake difference was observed in pancreatic tissue slices from patients with T1DM, T2DM or healthy controls. The in vivo porcine pancreatic uptake reached a peak of standardized uptake value (SUV) of 2.8 with a low distribution volume ratio in all animals. Moderate to high tracer uptake was identified in the bile system and in bone.Conclusions[¹⁸F]-FE-(+)-DTBZ binds to vesicular monoamine transporter 2 (VMAT2) with high specificity in pure islet tissue in vitro. However, there is high nondisplaceable binding to exocrine tissue. In addition, in vivo tracer metabolism and dehalogenation result in severe underestimation of porcine pancreatic VMAT2 expression and BCM. The results do not support [¹⁸F]-FE-(+)-DTBZ as a suitable tracer for in vivo beta-cell imaging.     

Improved minimal residual disease detection by targeted quantitative polymerase chain reaction in Nucleophosmin 1 type a mutated acute myeloid leukemia

Multicolor flow cytometry (MFC) and real‐time quantitative PCR (RQ‐PCR) are important independent techniques to determine minimal residual disease (MRD) in acute myeloid leukemia (AML). MFC is the standard method, but may be unreliable. Therefore, MFC‐based determination of MRD with an RQ‐PCR‐based approach targeting the nucleophosmin 1 (NPM1) type A mutation was set out to compare. Since most current NPM1 RQ‐PCR MRD protocols suffer from clear definitions of quantifiability, we sought to define quantifiability in a reproducible and standardized manner. The limit of quantifiability of our RQ‐PCR protocol for the NPM1 type A mutation varied between 0.002% and 0.04% residual leukemic cells depending on the features of the standard curve for each PCR experiment. The limit of detection was close to 0.001% leukemic cells. The limit of detection by MFC ranged from 0.01% to 1% depending on the phenotype of the leukemic cells as compared with non‐leukemic bone marrow cells. Forty‐five MRD samples from 15 patients using both NPM1 mutation specific RQ‐PCR and MFC were analyzed. In 32 of the 45 samples (71%), an MRD‐signal could be detected with RQ‐PCR. A quantifiable NPM1 mutation signal was found in 15 samples (33%) (range 0.003%–2.6% leukemic cells). By contrast, only two follow‐up samples (4%) showed residual leukemic cells (0.04% and 0.3%, respectively) by MFC. Thus, RQ‐PCR of the NPM1 type A mutation was more sensitive and reliable than MFC for determination of MRD, which might have clinical implications. © 2016 Wiley Periodicals, Inc.     

Retrospectively gated MRI for in vivo assessment of endothelium‐dependent vasodilatation and endothelial permeability in murine models of endothelial dysfunction

Endothelial dysfunction is linked to impaired endothelial‐dependent vasodilatation and permeability changes. Here, we quantify both of these phenomena associated with endothelial dysfunction by MRI in vivo in mice. Endothelial function was evaluated in the brachiocephalic artery (BCA) and left carotid artery (LCA) in ApoE/LDLR^?/? and high‐fat diet (HFD)‐fed mice as compared with control mice (C57BL/6J). The 3D IntraGate® FLASH sequence was used for evaluation of changes in vessels’ cross‐sectional area (CSA) and volume following acetylcholine (Ach) administration. Evaluation of endothelial permeability after administration of contrast agent (Galbumin, BioPAL) was based on the variable flip angle method for the assessment of parameters based on the relaxation time (T₁) value. In order to confirm the involvement of nitric oxide (NO) in response to Ach, L‐NAME‐treated mice were also analyzed. To confirm that endothelial permeability changes accompany the impairment of Ach‐dependent vasodilatation, permeability changes were analyzed in isolated, perfused carotid artery. In C57BL/6J mice, Ach‐induced vasodilatation led to an approximately 25% increase in CSA in both vessels, which was temporarily dissociated from the effect of Ach on heart rate. In ApoE/LDLR^?/? or HFD‐fed mice Ach induced a paradoxical vasoconstriction that amounted to approximately 30% and 50% decreases in CSA of BCA and LCA respectively. In ApoE/LDLR^?/? and HFD‐fed mice endothelial permeability in BCA was also increased (fall in T₁ by about 25%). In L‐NAME‐treated mice Ach‐induced vasodilatation in BCA was lost. In isolated, perfused artery from ApoE/LDLR^?/? mice endothelial permeability was increased. MRI‐based assessment of endothelium‐dependent vasodilatation induced by Ach and endothelial permeability using a retrospectively self‐gated 3D gradient‐echo sequence (IntraGate® FLASH) enables the reliable detection of systemic endothelial dysfunction in mice and provides an important tool for the experimental pharmacology of the endothelium in murine models of diseases in vivo. Copyright © 2016 John Wiley & Sons, Ltd.     

Red blood cells stimulate fibroblast-mediated contraction of three dimensional collagen gels in co-culture

OBJECTIVE AND DESIGN: Following injury, red blood cells (RBC) may interact with extracellular matrix (ECM). In the present study we hypothesised that RBC, and soluble factors from RBC, might mediate remodelling of ECM by affecting fibroblast-mediated contraction of three dimensional collagen gels. MATERIALS AND METHODS: Human lung fibroblasts (HFL-1), were cultured together with isolated RBC, conditioned medium from RBC (RBC-CM) and hemolysed RBC in type I collagen gels. Gel contraction was determined by an image analyser. RESULTS: Both RBC, RBC-CM and hemolysed RBC stimulated gel contraction by fibroblasts (P < 0.001), compared to fibroblasts alone. The RBC-CM stimulated (P < 0.01) gel contraction in a time and concentration dependent manner. A similar effect was observed when supernatant from hemolysed RBC was tested. The production of fibronectin was increased (P < 0.01) in the co-culture system, compared to fibroblasts cultured alone. CONCLUSIONS: The present study shows that RBC can interact with mesenchymal cells in vitro. The ability of RBC to modulate fibroblast-mediated contraction in vitro, might therefore be an important mechanism regulating repair processes after injury.     

Glucocorticoids modulate TGF-beta production

TGF- is thought to play a central role in pulmonary fibrosis inducing fibroblast differentiation and extracellular matrix synthesis. In human lung fibroblasts, it is still unclear how various TGB- isoforms affect TGF- production and whether glucocorticoids, commonly used agents to treat fibrotic lung disease, modulate these processes. To this end, human fetal lung fibroblasts (HFL-1) were cultured with various concentrations of glucocorticoids (budesonide, dexamethasone or hydrocortisone) with and without TFG-1, -2, and -3. TGF- mRNA was assessed by real time RT-PCR. Smad 2, 3, and 4 and AP-1 complex (c-fos and c-Jun) cellular localization were evaluated by immunostaining. TGF-2 and -3 stimulated TGF-1 production significantly (p < 0.01 relative to control). TGF-1 stimulated TGF-2 production (p < 0.01 relative to control). TGF-3 was undetectable. Glucocorticoids significantly inhibited TGF-1 and -2 production and reduced expression of the upregulated TGF-1 and -2 mRNA induced by exogenous TGF-1, -2 or -3 (p < 0.01 for each) but had no effect on Smads. Although c-jun-related nuclear staining was not intensified in TGF--stimulated cells, it was reduced by glucocorticoids. Thus, TGF- isoforms may stimulate production of various TGF- isoforms in the lung. Glucocorticoids then may block TGF- production by modulating mRNA levels and c-Jun.