Metabolism of 8-prenylnaringenin, a potent phytoestrogen from hops (Humulus lupulus), by human liver microsomes.

The female flowers of hops are used throughout the world as a flavoring agent for beer. Recently, there has been increasing interest in the potential estrogenic properties of hop extracts. Among the possible estrogenic compounds in hops, 8-prenylnaringenin is perhaps most significant due to its high in vitro potency exceeding that of other known phytoestrogens. Since data regarding the pharmacokinetic properties of this compound are lacking, we investigated the in vitro metabolism of 8-prenylnaringenin by human liver microsomes. A total of 12 metabolites were identified, and biotransformation occurred on the prenyl group and the flavanone skeleton. The major site of oxidation was on the terminal methyl groups, and of the two possible isomers, the transisomer was more abundant. The double bond on the prenyl group was also oxidized to an epoxide that was opened by intramolecular reaction with the neighboring hydroxyl group. On the flavanone skeleton, the major site of oxidation was at 3'position on the B ring. Other metabolites included oxidation at carbon-3 as well as desaturation of the C ring to produce 8-prenylapigenin. An unusual hydroxy quinone product formed by ipso hydroxylation of the B ring of 8-prenylnaringenin was also detected. This product was probably an intermediate for the B ring cleavage product, 8-prenylchromone.     

Estimation of Nanoporous Au Young’s Modulus from Serial Block Face-SEM 3D-Characterisation

Nanoporous Au has been subjected to serial block face-scanning electron microscopy (SBF-SEM) 3D-characterisation. Corresponding sections have been digitalized and used to evaluate the associated mechanical properties. Our investigation demonstrates that the sample is homogeneous and isotropic. The effective Young’s modulus estimated by an analytical multiscale approach agrees remarkably well with the values stated in the literature.     

Comparing Digital Therapeutic Intervention with an Intensive Obesity Management Program: Randomized Controlled Trial

In this study, we evaluated whether the digital program Vitadio achieves comparable results to those of an intensive in-person lifestyle intervention in obesity management. This is a 12-month prospective, randomized controlled trial. Obese patients with insulin resistance, prediabetes or type 2 diabetes were included. The intervention group (IG) used Vitadio. The control group (CG) received a series of in-person consultations. Body weight and various metabolic parameters were observed and analyzed with ANOVA. The trial is ongoing and the presented findings are preliminary. Among 100 participants (29% men; mean age, 43 years; mean BMI, 40.1 kg/m²), 78 completed 3-month follow-up, and 51 have completed the 6-month follow-up so far. Participants significantly (p < 0.01) reduced body weight at 3 months (IG: −5.9 ± 5.0%; CG: −4.2 ± 5.0%) and 6 months (IG: −6.6±6.1%; CG: −7.1 ± 7.1%), and the difference between groups was not significant. The IG achieved favorable change in body composition; significant improvement in TAG (−0.6 ± 0.9 mmol/l, p < 0.01), HDL (0.1 ± 0.1%, p < 0.05), HbA1c (−0.2 ± 0.5%, p < 0.05) and FG (−0.5 ± 1.5 mmol/l, p < 0.05); and a superior (p = 0.02) HOMA-IR reduction (−2.5 ± 5.2, p < 0.01). The digital intervention achieved comparable results to those of the intensive obesity management program. The results suggest that Vitadio is an effective tool for supporting patients in obesity management and diabetes prevention.     

Attenuation of renal ischaemic injury by felodipine

Summary Felodipine is a vasodilating calcium channel blocker of the dihydropyridine type. The effects of felodipine on post-ischaemic renal function were evaluated in rats subjected to bilateral renal artery occlusion for 30 or 60 min.In a first set of experiments the recovery of renal function after 30 or 60 min of renal artery occlusion was followed intermittently for 16 days by endogenous creatinine clearance. Renal function was better preserved in rats given felodipine (45 nmol/kg i.v.) during the occlusion period than in vehicle-treated control rats. The survival rate after 60-min occlusion was 11% in controls but 70% in the felodipine-treated rats. After occlusion for 30 min the survival rate was similar in the two groups, but renal function recovered faster in the felodipine group than in the controls.In a second series, acute renal damage was evaluated by the extent of erythrocytes trapped in the kidney after 30-min reperfusion following 60-min renal artery occlusion. Felodipine administration (45 nmol/kg) during the occlusion reduced renal damage compared with vehicle controls. Kidney weight and systemic haematocrit were also better maintained in the felodipine-treated rats. Furthermore, renal damage was reduced by the t-butyl analogue or felodipine, H 186/86, which is devoid of vasodilatory effects. The results demonstrate that treatment with the vasodilator calcium channel blocker felodipine protects the kidney from ischaemic/reperfusion injuries. The tissue protection is not related to the haemodynamic effects alone, since the haemodynamically inactive dihydropyridine H 186/86 also reduced the extent of renal damage. An additional antiperoxidant or scavanger-like effect inherent in the dihydropyridine molecule is suggested. Send offprint requests to M. Nordlander at the above address     

Adriamycin-induced histamine release from heart tissue in vitro

 It has been proven that the anthracyclines induce an important, noncytotoxic histamine release from rat peritoneal mast cells. As mast cells derived from different tissues exhibit marked heterogeneity, the effect of Adriamycin in comparison with other antineoplastic agents was tested on fragments of the right heart auricle, which contain a great number of mast cells. In this experimental model, Adriamycin induced a dose-dependent histamine release that was significantly limited by the antiexocytotic drug sodium cromoglycate. The antineoplastic agents cisplatin and 5-fluorouracil, in contrast, did not provoke any comparable histamine release. In the formulation employed in clinical settings, paclitaxel was also capable of inducing a histamine release comparable with that of Adriamycin; the exocytotic activity, however, was also evident when the tissue fragments were treated with Cremophor EL alone, without the addition of paclitaxel, whereas treatment of samples with paclitaxel dissolved in ethanol did not induce any releasing action. These data thus suggest that the secretory activity should be ascribed to the solvent Cremophor EL and not to paclitaxel. The release of histamine induced by paclitaxel in Cremophor EL/ethanol was also limited by sodium cromoglycate. These results again indicate that histamine release from mast cells derived not only from the peritoneal cavity but also from the cardiac tissue could play a role in the cardiotoxicity of anthracyclines and of paclitaxel in the clinically employed formulation. Received: 18 August 1996 / Accepted: 22 December 1996     

Combined therapy with bevacizumab and photodynamic therapy for myopic choroidal neovascularization:A one-year follow-up controlled study

AIM: To evaluate the efficacy and safety of a combined treatment for myopic choroidal neovascularization (CNV) using photodynamic therapy (PDT) and intravitreal bevacizumab and to compare it with intravitreal bevacizumab monotherapy.METHODS: Thirty-four eyes with angiographic evidence of myopic CNV were randomly divided into two groups:17 were treated with one intravitreal bevacizumab injection (1.25 mg) and low-fluence-rate PDT within seven days of the injection (Group A). The other 17 received monotherapy with bevacizumab injections (Group B). Clinical evidence of complications, best corrected visual acuity (BCVA) and fluorescein leakage were evaluated. BCVA and optical coherence tomography (OCT) were evaluated monthly. The timepoints follow-up was established at 6 and 12mo. All patients were retreated following a PRN protocol.RESULTS:A total of 34 eyes of 34 patients (26 women and 8 men) with a mean age of 62.35 years were included. In Group A (17 eyes) the mean BCVA increased from 0.55±0.13 logMAR before the treatment to 0.40±0.09 logMAR at the 12mo follow-up (P<0.01). In Group B (17 eyes) the mean BCVA increased from 0.60±0.11 logMAR before the treatment to 0.55±0.12 logMAR at the 12mo follow-up (P<0.01). There was no statistically significant difference between the two groups in terms of LogMar visual acuity. In Group A the mean number of combined treatments was 1.8±0.11 per patient; in Group B the mean number of intravitreal bevacizumab injections was 3.1±0.08 per patient. The number of treatments was significantly fewer in Group A (P<0.01). No local or systemic side effects occurred among any of the patients treated in this study.CONCLUSION:The combination of anti-angiogenic injections and PDT appears to be a safe and effective option for myopic CNV treatment and allows for a significant reduction of intravitreal injections.