Long survival of primary cerebral lymphoma with progressive radiation necrosis

A 56-year-old man lived 8 years after excision and irradiation of a primary cerebral lymphoma. Delayed radiation necrosis caused progressive neurologic deterioration and probably his steroid-responsive episodes of obtundation. Vasogenic edema induced by radiation may account for the latter. An incidental extraneural lymphoma was found postmortem without evidence of CNS lymphoma.     

Emergence of the less common cannabinoid Δ8-Tetrahydrocannabinol in a doping sample

Δ⁸-Tetrahydrocannabinol (Δ⁸-THC) as isomer of the well-known Δ⁹-THC has a similar mode of action, and the potency was estimated to be two thirds compared with Δ⁹-THC. Content of Δ⁸-THC in plant material is low, but formulations containing Δ⁸-THC in high concentrations are gaining popularity. Δ⁸-THC is to be regarded as prohibited substance according to the Prohibited List of the World Anti-Doping Agency (WADA). Contradictory results between initial testing procedure and confirmatory quantitation for 11-Nor-9-carboxy-Δ⁹-tetrahydrocannabinol (Δ⁹-THC-COOH) of a doping control sample gave rise for follow-up testing procedures. After alkaline hydrolysis and liquid–liquid extraction, the sample was analyzed by high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) using isocratic elution instead of gradient elution, which is used for standard procedure. Isocratic elution resulted in two peaks instead of one using gradient elution. Both peaks showed same fragmentation. Using certified reference materials, one peak could be assigned to Δ⁹-THC-COOH and the other one with higher intensity to the less common 11-Nor-9-carboxy-Δ⁸-Tetrahydrocannabinol (Δ⁸-THC-COOH) in a concentration of approximately 1200 ng/ml. As complementary method, gas chromatography tandem mass spectrometry (GC-MS/MS) can also be used for identification. Here Δ⁸- and Δ⁹-THC-COOH can be distinguished by chromatography and by fragmentation. Additional investigations of doping control samples containing Δ⁹-THC-COOH revealed the simultaneous presence of Δ⁸-THC-COOH in low concentrations (0.22–8.91 ng/ml) presumably due to plant origin. Percentage of Δ⁸-THC-COOH varies from 0.05 to 2.83%. In vitro experiments using human liver microsomes showed that Δ⁸-THC is metabolized in the same way as Δ⁹-THC.     

HepG2 as promising cell-based model for biosynthesis of long-term metabolites: Exemplified for metandienone

In order to detect the abuse of substances in sports, the knowledge of their metabolism is of undisputable importance. As in vivo administration of compounds faces ethical problems and might even not be applicable for nonapproved compounds, cell-based models might be a versatile tool for biotransformation studies. We coincubated HepG2 cells with metandienone and D₃-epitestosterone for 14 days. Phase I and II metabolites were analyzed by high-performance liquid chromatography (HPLC)–tandem mass spectrometry and confirmed by gas chromatography–mass spectrometry (GC–MS). The metandienone metabolites formed by HepG2 cells were comparable with those renally excreted by humans. HepG2 cells also generated the two long-term metabolites 17β-hydroxymethyl-17α-methyl-18-nor-androst-1,4,13-trien-3-one and 17α-hydroxymethyl-17β-methyl-18-nor-androst-1,4,13-trien-3-one used in doping analyses, though in an inverse ratio compared with that observed in human urine. In conclusion, we showed that HepG2 cells are suitable as model for the investigation of biotransformation of androgens, especially for the anabolic androgenic steroid metandienone. They further proved to cover phase I and II metabolic pathways, which combined with a prolonged incubation time with metandienone resulted in the generation of its respective long-term metabolites known from in vivo metabolism. Moreover, we showed the usability of D₃-epitestosterone as internal standard for the incubation. The method used herein appears to be suitable and advantageous compared with other models for the investigation of doping-relevant compounds, probably enabling the discovery of candidate metabolites for doping analyses.     

Lack of efficacy of mono-mode of action therapeutics in COVID-19 therapy - How the lack of predictive power of preclinical cell and animal studies leads developments astray

The diverse experiences regarding the failure of tested drugs in the fight against COVID-19 made it clear that one should at least question the requirement to apply classical preclinical development strategies that demand cell and animal efficacy models to be tested before going into clinical trials. Most animals are not susceptible to infection with SARS-CoV-2, and so this led to one-sided virus replication experiments in cells and the use of animal models that have little in common with the complex pathogenesis of COVID-19 in humans. Therefore, non-clinical development strategies were designed to meet regulatory requirements, but they did not truly reflect the situation in the clinic. This has led the search for effective agents astray in many cases. As proof of this statement, we now bring together the results of such required preclinical experiments and compare with the results in clinical trials. Two clear conclusions that can be drawn from the experience to date: The required preclinical models are unsuitable for the development of innovative treatments medical devices in the case of COVID-19 and mono-action strategies (e.g. direct antivirals) are of very little or no benefit to patients under randomized,blinded conditions. Our hypothesis is that the complex situation of COVID-19 may benefit from multi-mode drugs. Here, the molecular class of aptamers could be a solution.     

Die Klinische Bedeutung von Hodenexperimenten

Ohne ZusammenfassungVortrag, gehalten auf der Naturforscher- und Ärzteversammlung zu Leipzig am 21. Sept. 1922.     

Tierexperimentelle Untersuchungen zur Frage der Folgen der Sterilisation vor der Pubert?t bei Knaben

Zusammenfassung An 37 ♂ Meerschweinchen im Alter von 10–14 Tagen und 3 Monaten werden die Ductus deferentes reseziert, um zu prüfen, obvor der Pubert?t durch diese Operation die Hoden sp?ter Schaden erleiden, ob die Spermatogenese erhalten bleibt und ob der Eingriff sich irgendwie sch?dlich auf den Gesamtorganismus auswirkt. Unsere Versuche ergaben, da? dieSpermatogenese nach derartiger frühzeitiger Passageunterbrechung der Samenleiter erhalten bleibt. Es werden lebende und lebensf?hige Spermatozoen gebildet, was entscheidend für diese Frage ist.Die Tiere entwickeln sich normal. Ausfallserscheinungen treten nicht auf. Durch die mühevollen Arbeiten ist ein ?u?erst wichtiges Problem in der Rassenfrage gel?st. Sie sind grundlegend und richtunggebend für unsere künftigen Ma?nahmen zur Verhütung erbkranken Nachwuchses. Mit 6 Textabbildungen     

Two distinct receptors account for recognition of maleyl-albumin in human monocytes during differentiation in vitro.

A comparison of the receptor-mediated interaction of malondialdehyde-low density lipoprotein and maleyl-albumin has been examined in human monocytes during differentiation in vitro. The recognition of both ligands by the scavenger receptor of these cells has been confirmed. We now report that human monocytes express a second cellular surface receptor for maleyl-albumin that is distinct from the scavenger receptor. The activity of the maleyl-albumin receptor, determined by both binding and lysosomal hydrolytic assays, substantially exceeds that of the scavenger receptor in freshly isolated monocytes. A dramatic and rapid decline in the activity of the maleyl-albumin receptor occurs within 72 to 96 h during differentiation in vitro. At day 7, while only 5-10% of the original activity of the maleyl-albumin receptor remains, it is similar to that of the maximally expressed scavenger receptor. Both the binding and hydrolysis of ligand mediated by the maleyl-albumin receptor are specifically inhibited by alpha-casein and alkaline-treated albumin; neither of these proteins is recognized by the scavenger receptor. The occurrence of the exceptionally active maleyl-albumin receptor on freshly isolated human monocytes suggests that it participates in processes necessary to the function of the cells that diminish in importance after differentiation of the monocytes into macrophages in vitro. Furthermore, while maleyl-albumin is a useful adjunct to studies of cellular events mediated by the scavenger receptor, the presence of a second receptor for maleyl-albumin must be taken into account as a potential contributing and complicating event.     

Scavenger receptor-mediated recognition of maleyl bovine plasma albumin and the demaleylated protein in human monocyte macrophages.

Maleyl bovine plasma albumin competed on an equimolar basis with malondialdehyde low density lipoprotein (LDL) in suppressing the lysosomal hydrolysis of 125I-labeled malondialdehyde LDL mediated by the scavenger receptor of human monocyte macrophages. Maleyl bovine plasma albumin, in which 94% of the amino groups were modified, exhibited an anodic mobility in agarose electrophoresis 1.7 times that of the native protein. Incubation of maleyl bovine plasma albumin at pH 3.5 regenerated the free amino groups and restored the protein to the same electrophoretic mobility as native albumin. The demaleylated protein suppressed 75% of the hydrolysis of 125I-labeled malondialdehyde LDL and greater than 80% of 125I-labeled maleyl bovine plasma albumin. The ability of the demaleylated protein to compete was abolished after treatment with guanidine hydrochloride. Although ligands recognized by the scavenger receptor typically are anionic, we propose that addition of new negative charge achieved by maleylation, rather than directly forming the receptor binding site(s), induces conformational changes in albumin as a prerequisite to expression of the recognition domain(s). The altered conformation of the modified protein apparently persists after removal of the maleyl groups. We conclude that the primary sequence of albumin, rather than addition of new negative charge, provides the recognition determinant(s) essential for interaction of maleyl bovine plasma albumin with the scavenger receptor.     

Inversin relays Frizzled-8 signals to promote proximal pronephros development

Mutations of inversin cause type II nephronophthisis, an infantile autosomal recessive disease characterized by cystic kidney disease and developmental defects. Inversin regulates Wnt signaling and is required for convergent extension movements during early embryogenesis. We now show that Inversin is essential for Xenopus pronephros formation, involving two distinct and opposing forms of cell movements. Knockdown of Inversin abrogated both proximal pronephros extension and distal tubule differentiation, phenotypes similar to that of Xenopus deficient in Frizzled-8. Exogenous Inversin rescued the pronephric defects caused by lack of Frizzled-8, indicating that Inversin acts downstream of Frizzled-8 in pronephros morphogenesis. Depletion of Inversin prevents the recruitment of Dishevelled in response to Frizzled-8 and impeded the accumulation of Dishevelled at the apical membrane of tubular epithelial cells in vivo. Thus, defective tubule morphogenesis seems to contribute to the renal pathology observed in patients with nephronophthisis type II.