Synthetic Evolution of a Supramolecular Harpooning Mechanism to Immobilize Vesicles at Antifouling Interfaces

The immobilization of vesicles has been conceptualized as a method to functionalize biointerfaces. However, the preservation of their integrity post immobilization remains a considerable challenge. Interfacial interactions can cause vesicle rupture upon close surface contact and non-specific protein adsorption impairing surface functions. To date, immobilization of vesicles has relied solely on either entrapment or prior modification of vesicles, both of which require laborious preparation and limit their applications. This work develops a bioinspired strategy to pin vesicles without prior modification while preserving their intact shape. This work introduces antifouling diblock copolymers and ultrathin surface-attached hydrogels containing a brush-like interface consisting of a bottle brush copolymer of N-(2-hydroxypropyl) methacrylamide (HPMA) and N-(3-methacrylamidopropyl)-N,N-dimethyldodecan-1-aminiumiodide (C12+). The presence of positive charges generates an attractive force that pulls vesicles toward the surface. At the surface, the amphiphilic properties of the combs facilitate their insertion into the membrane, mimicking the harpooning mechanism observed in antimicrobial peptides. Importantly, the antifouling poly(HPMA) backdrop serves to safeguard the vesicles by preventing deformation and breakage. Using a combination of thermodynamic analysis, surface plasmon resonance, and confocal laser scanning microscopy, this work demonstrates the efficiency of this biomimetic system to capture vesicles while maintaining an antifouling interface necessary for bioapplications.     

Contact allergy to trimethylolpropane triacrylate (TMPTA) in an aziridine plastic hardener

4 workers developed hand and face dermatitis when exposed to a floor top coal. This contained a polyurethane arid a polyfunctional aziridine hardener and additives. The aziridine hardener was made by reacting propyleneimine with a polyfunctional acrylate, trimethylolpropane triacrylate (TMPTA). All 4 reacted to the hardener and to TMPTA, which is present in excess, 2 of them also reacted to pentacrythritol triacrylate (PETA), which can be used in the production of aziridine hardeners. TMPTA and PETA cross-react, and are known sensitizers in UV-hardening acrylates.
The present finding shows that well-known sensitizers can be found in hidden sources when used in a quite different chemical process.     

Receptor status (ER and PgR) determined with histochemical and biochemical methods in breast carcinoma]

Recently, a method similar to ER.ICA has been proposed for the progesterone receptor (PgR) using two monoclonal antibodies, JZB39 and KD68, specific for human PgR and characterized by a molecular weight of 95 and 120 Kd, respectively. A series of 73 breast cancer patients was studied with regards to ER and PgR using both immunocytochemical (ICA) and biochemical (DCC) assays. Results showed no substantial differences between the two methods when considering common clinical-pathological parameters. Overall agreement between ICA and DCC methods was found: 79% for PgR and 78% for ER. A slight quantitative correlation was also observed between the "score values" of the ICA method and the Fmol content of ER and PgR using the Brave-Pearson test (r = 0.49 for PgR; r = 0.43 for ER). Specificity of PgR.ICA method was 77% for PgR and 72% for ER; sensitivity was 82% and 83%, respectively. The ICA method is a reliable technique to assess PgR presence as well as ER. Further studies are necessary to evaluate the prognostic role of nuclear PgR.     

Spontaneous Reversal of P‐Glycoprotein Expression in Multidrug Resistant Cell Lines*

Abstract: Increased expression of P‐glycoprotein encoded by the mdr‐1 gene is a well‐characterised mechanism for resistance to cancer chemotherapeutic drugs in cell lines. However, the P‐glycoprotein expression after removal of the selection pressure has not fully been elucidated. The stability of P‐glycoprotein expression in the presence (+) and absence (?) of vincristine (30 or 150 nM) was studied in multidrug resistant K562 cell lines (VCR30+, VCR150+, VCR30? and VCR150?) for 11 months. The P‐glycoprotein protein and mdr‐1 mRNA levels were determined at regular intervals using flow cytometry and real‐time PCR, respectively. Chemosensitivity to a panel of antineoplastic drugs was measured using an MTT assay. The presence of vincristine (VCR30+ and VCR150+) resulted in high and stable levels of P‐glycoprotein and mdr‐1 mRNA during the whole period compared to wild type. As for the VCR30? and VCR150? subcultures, the expressions of P‐glycoprotein and mdr‐1 mRNA were stable for five months, and then the levels decreased rapidly. Concomitantly, the sensitivity to drugs known as P‐glycoprotein substrates was restored. In conclusion, resistant cells growing in the presence of the inducing drug have a stable P‐glycoprotein expression and resistance level, but removing the inducing drug may result in a sudden and rapid lowering of P‐glycoprotein and mdr‐1 mRNA levels as long as five months after drug withdrawal.     

Pharmacodynamic differences between species exemplified by the novel anticancer agent CHS 828

When a candidate drug enters clinical trials, decisions regarding dosing are mainly based on animal data. Occasionally, toxicity problems are faced in the clinic because of unexpected species differences in pharmacokinetics or pharmacodynamics between humans and preclinical species. Fludarabine and topotecan are examples of such drugs. In the first clinical trials of the new agent CHS 828, the maximum tolerated dose was reached earlier than expected from animal data. This paper discusses the issue of species differences in the development of anticancer drugs, and preclinical models for detection and quantification of such differences. Pharmacokinetic and hematological toxicity data of CHS 828 from studies in rats and humans are presented. In vitro sensitivity to CHS 828 and some established cytotoxic agents was measured in lymphocytes from humans and rats and in a panel of human and rodent cell‐lines. 10–100 times higher CHS 828 exposure was tolerated by rats than by patients. In both in vitro cell systems, CHS 828 showed higher potency in human cells compared to rodent cells. A species difference was evident also for fludarabine, but not for doxorubicin and cisplatin. CHS 828 pharmacokinetics were similar across species. In conclusion, the lower tolerance of CHS 828 in humans than in rats could be detected in vitro in cultures of peripheral lymphocytes. Preclinical studies of species differences could help the interpretation of in vivo effect studies as well as the choice of starting dose for clinical trials. We suggest peripheral lymphocytes from different species as a potential model system for such studies. Drug Dev. Res. 61:218–226, 2004. © 2004 Wiley‐Liss, Inc.     

Gemcitabine plus cisplatin for advanced transitional cell carcinoma of the urinary tract: a phase II multicenter trial

PURPOSE: We determined the activity and toxicity of gemcitabine plus cisplatin in patients with inoperable or metastatic transitional cell carcinoma of the urinary tract. MATERIALS AND METHODS: A total of 54 patients with transitional cell carcinoma, measurable disease and Eastern Cooperative Oncology Group performance status 2 or greater were enrolled in this multicenter phase II trial. Previous adjuvant or neoadjuvant therapy for locally advanced disease was acceptable if it had been completed more than 1 year before study entry. Every 4 weeks patients received 1,000 mg./m.2 gemcitabine intravenously on days 1, 8 and 15, and 70 mg./m.2 cisplatin intravenously on day 2. RESULTS: All patients were evaluable for response and toxicity. Notably only 7 of the 54 patients (13%) previously received chemotherapy in an adjuvant or neoadjuvant setting. Overall we observed 26 objective responses (48%), of which 15% were complete. Median time to progression was 23 weeks and median survival was 54 weeks. Treatment was well tolerated. The main toxicities were leukopenia (grade 3 in 28% and grade 4 in 11% of patients), anemia (grade 3 in 34% and grade 4 in 6%) and thrombocytopenia (grade 3 in 14% and grade 4 in 6%). Other relevant side effects were nausea and vomiting in 20% of cases, fever in 24%, alopecia in 22%, renal failure in 7.4% and mucositis in 2%. CONCLUSIONS: Combined cisplatin plus gemcitabine is highly active in advanced transitional cell carcinoma of the urinary tract with manageable toxicity. The response rate, time to treatment failure and overall survival appeared to be comparable to those achieved with combined methotrexate, vinblastine, doxorubicin and cisplatin. Conversely toxicity appeared lower. Evaluation of this regimen in randomized studies with methotrexate, vinblastine, doxorubicin and cisplatin is strongly suggested.     

Uptake and disposition of inhaled methanol vapor in humans.

Methanol is a widely used solvent and a potential fuel for motor vehicles. Human kinetic data of methanol are sparse. As a basis for biological exposure monitoring and risk assessment, we studied the inhalation toxicokinetics of methanol vapor in four female and four male human volunteers during light physical exercise (50 W) in an exposure chamber. The relative uptake of methanol was about 50% (range 47-53%). Methanol in blood increased from a background level of about 20 to 116 and 244 microM after 2 h exposure at 0, 100 ppm (131 mg/m3) and 200 ppm (262 mg/m3), respectively. Saliva showed substantially higher levels than blood immediately after exposure. This difference disappeared in a few minutes; thereafter the concentrations and time courses in blood, urine, and saliva were similar, with half times of 1.4, 1.7, and 1.3 h, respectively. The postexposure decrease of methanol in exhaled air was faster, with a half time of 0.8 h. The methanol concentrations were approximately twice as high in all four types of biological samples at 200 compared to 100 ppm. No increase in urinary formic acid was seen in exposed subjects. Our study indicates non-saturated, dose-proportional kinetics of methanol up to 200 ppm for 2 h. No gender differences were detected. Similar, parallel patterns were seen with regard to the methanol time courses in blood, urine, and saliva, whereas the concentration in exhaled air decreased markedly faster. Thus, apart from blood and urine, saliva also seems suitable for biomonitoring of methanol exposure.