Improved tumor targeting of anti-epidermal growth factor receptor Nanobodies through albumin binding: taking advantage of modular Nanobody technology

The approximately 15-kDa variable domains of camelid heavy-chain-only antibodies (called Nanobodies) can easily be formatted as multivalent or multispecific single-chain proteins. Because of fast excretion, however, they are less suitable for therapy of cancer. In this study, we aimed for improved tumor targeting of a bivalent anti-epidermal growth factor receptor (EGFR) Nanobody (alphaEGFR-alphaEGFR) by fusion to a Nanobody unit binding to albumin (alphaAlb). Biodistributions of alphaEGFR-alphaEGFR, alphaEGFR-alphaEGFR-alphaAlb ( approximately 50 kDa), alphaTNF-alphaTNF-alphaAlb (control, binding tumor necrosis factor-alpha), and the approximately 150-kDa anti-EGFR antibody cetuximab were compared in A431 xenograft-bearing mice. The proteins were radiolabeled with (177)Lu to facilitate quantification. Tumor uptake of (177)Lu-alphaEGFR-alphaEGFR decreased from 5.0 +/- 1.4 to 1.1 +/- 0.1 %ID/g between 6 and 72 h after injection. Due to its rapid blood clearance, tumor-to-blood ratios >80 were obtained within 6 h after injection. Blood clearance became dramatically slower and tumor uptake became significantly higher by introduction of alphaAlb. Blood levels of alphaEGFR-alphaEGFR-alphaAlb were 21.2 +/- 2.5, 11.9 +/- 0.6, and 4.0 +/- 1.4 and tumor levels were 19.4 +/- 5.5, 35.2 +/- 7.5, and 28.0 +/- 6.8 %ID/g at 6, 24, and 72 h after injection, respectively. Tumor uptake was at least as high as for cetuximab (15.5 +/- 3.9, 27.1 +/- 7.9, and 25.6 +/- 6.1 %ID/g) and significantly higher than for alphaTNF-alphaTNF-alphaAlb. alphaEGFR-alphaEGFR-alphaAlb showed faster and deeper tumor penetration than cetuximab. These data show that simple fusion of alphaEGFR and alphaAlb building blocks results in a bifunctional Nanobody format, which seems more favorable for therapy as far as pharmacokinetics and tumor deposition are concerned.     

Steroid- and calcineurin inhibitor free immunosuppression in kidney transplantation: state of the art and future developments

Owing to the increasing disparity of organ demand and organ supply the search for optimal immunosuppressive strategies has become a central issue in kidney transplantation (KTX). In the focus today are modifications of the use of calcineurin-inhibitors (CNIs, Cyclosporine A/Tacrolimus) and steroids, as they are nephrotoxic and promote cardiovascular risk factors like arterial hypertension, hyperlipidemia and diabetes mellitus. These modifications can either be withdrawal or avoidance of these substances in combination with new and/or established immunosuppressants. Because about half of all KTXs are performed by or with the help of urologists’ knowledge of modern immunosuppressive regimens is crucial also for urologists. We performed a literature research (PubMed, DIMDI, medline) for CNI- and steroid-sparing protocols and studies to elucidate their influence on graft-function and graft- and patient-survival. New substances and actual studies were also evaluated. Several published reports on CNI- and steroid-sparing protocols after KTX exist, including withdrawal, reduction or avoidance. The time of reduction seems to be crucial: an initially increased immune response should be counterbalanced by an initially intensified immunosuppression. Therefore, late steroid withdrawal seems to be safer than early withdrawal especially in Cyclosporine-based immunosuppression. Steroid avoidance also seems feasible on a CNI based regimen, especially in context with induction therapy. Withdrawal or avoidance of CNIs seems feasible with mycophenolate acid and/or induction therapy with IL 2-receptor antibodies as co-immunosuppressants. This is of interest in grafts with deteriorating function or from donors with extended criteria. Also, CNI- and steroid-free immunosuppression can be successfully performed with new immunosuppressants but results are yet premature. CNI- and/or steroid reduction, withdrawal or even avoidance is feasible. As long-term graft function is the goal of KTX and as more kidneys from donors with extended criteria are transplanted “tailored immunosuppression” will replace standards in the future.     

Elevated platelet count as a cause of abnormal von Willebrand factor multimer distribution in plasma

Twelve of 19 patients with myeloproliferative disorders showed a decrease of absence of the largest multimers of plasma von Willebrand factor (vWF) that correlated with elevated platelet counts but not with leukocyte counts. This suggested that platelets, rather than leukocytes, may be associated with the pathogenesis of the acquired vWF abnormality seen in these patients. To examine the hypothesis further, we studied 12 patients with reactive thrombocytosis after splenectomy. Increased platelet count (> 5 x 10(11)/L) after splenectomy was associated with vWF abnormalities indistinguishable from those detected in patients with myeloproliferative disorders. Accordingly, there was an inverse correlation between proportion of large vWF multimers and platelet, but not leukocyte, number: normalization of the platelet count was accompanied by restoration of a normal vWF multimeric pattern. These findings suggest that an increase in the number of platelets circulating in blood may favor the adsorption of larger vWF multimers onto the platelet membrane, resulting in their removal from the circulation and subsequent degradation.     

Rektale Magenschleimhautheterotopie

Heterotopic gastric mucosa is a rare finding in the rectum. Apart from two other hypotheses, a misdifferentiation of entodermal stem cells is the most widely accepted aetiopathogenetic assumption today. Due to acid secretion, the lesions predominantly manifest with hematochezia. Therapeutic options include medicinal therapy and particularly (endoscopic) removal. From the pathologist??s point of view a careful evaluation is required also in terms of basically possible dysplastic or malignant changes.     

Generalisierter Krampfanfall während der Anlage einer axillären Plexusblockade

Die Anaesthesiologie - Eine junge Patientin erleidet während der Anlage einer axillären Plexusblockade einen generalisierten Krampfanfall. Die Mechanismen, im Wesentlichen die vermutlich...     

Randomized Phase 2b Trial of Tofacitinib (CP‐690,550) in De Novo Kidney Transplant Patients: Efficacy,Renal Function and Safety at 1 Year

In this Phase 2b study, 331 low‐to‐moderate risk de novo kidney transplant patients (approximately 60% deceased donors) were randomized to a more intensive (MI) or less intensive (LI) regimen of tofacitinib (CP‐690, 550), an oral Janus kinase inhibitor or cyclosporine (CsA). All patients received basiliximab induction, mycophenolic acid and corticosteroids. Primary endpoints were: incidence of biopsy‐proven acute rejection (BPAR) with a serum creatinine increase of ≥0.3 mg/dL and ≥20% (clinical BPAR) at Month 6 and measured GFR at Month 12. Similar 6‐month incidences of clinical BPAR (11%, 7% and 9%) were observed for MI, LI and CsA. Measured GFRs were higher (p < 0.01) at Month 12 for MI and LI versus CsA (65 mL/min, 65 mL/min vs. 54 mL/min). Fewer (p < 0.05) patients in MI or LI developed chronic allograft nephropathy at Month 12 compared with CsA (25%, 24% vs. 48%). Serious infections developed in 45%, 37% and 25% of patients in MI, LI and CsA, respectively. Anemia, neutropenia and posttransplant lymphoproliferative disorder occurred more frequently in MI and LI compared with CsA. Tofacitinib was equivalent to CsA in preventing acute rejection, was associated with improved renal function and less chronic allograft histological injury, but had side‐effects at the doses evaluated.     

Determination of optic cup depth by confocal scanning laser tomography

PURPOSE: To assess whether confocal scanning laser tomography of the optic disc and clinical ophthalmoscopy using stereoscopic optic disc photographs, agree in the evaluation of the deepest part of the optic cup. PATIENTS AND METHODS: The study included 33 eyes of patients with focal normal-pressure glaucoma. Using 15 degrees color stereoscopic optic disc photographs and dividing the optic disc into an upper and a lower half, two trained observers independently established the location of the deepest part of the cup. By selection, the two observers had made congruent judgements for all eyes in the study. All patients also underwent confocal scanning laser tomography of the optic disc using the Heidelberg Retina Tomograph (HRT). The location of the deepest "mean cup depth" was noted. RESULTS: The deepest optic cup region based on stereoscopic evaluation of photographs and on scanning laser tomography did not correlate significantly with each other (p=0.18; chi-square test, linear-by-linear association). According to the scanning laser tomography data, the maximal optic cup depths were not correlated with the corresponding locations of maximal visual field defect (p=0.80). Using the stereo photographic data, the locations of maximal optic cup depth and maximal visual field defect were correlated (p=0.006). CONCLUSIONS: In some glaucomatous eyes, confocal scanning laser tomographic assessment of the location of the deepest optic cup region does not agree with clinical judgement and, in contrast to clinical examination, does not correlate with the location of the maximal visual field defect.