Search

The oxycyclohexyl acid BMS-986278 (33) is a potent lysophosphatidic acid receptor 1 (LPA1) antagonist, with a human LPA1 Kb of 6.9 nM. The structure-activity relationship (SAR) studies starting from the LPA1 antagonist clinical compound BMS-986020 (1), which culminated in the discovery of 33, are discussed. The detailed in vitro and in vivo preclinical pharmacology profiles of 33, as well as its pharmacokinetics/metabolism profile, are described. On the basis of its in vivo efficacy in rodent chronic lung fibrosis models and excellent overall ADME (absorption, distribution, metabolism, excretion) properties in multiple preclinical species, 33 was advanced into clinical trials, including an ongoing Phase 2 clinical trial in patients with lung fibrosis (NCT04308681).

The COVID-19 pandemic that caused unprecedented havoc on global tourism industry will all blow over, however whether the tourists' real-time on-site emotional experience in the reopened tourism destinations is higher or lower than that of the period before the pandemic outbreak has not been studied. Since this is an important basis for managers to design tourist win-back strategies, this study empirically examines the impact of the COVID-19 outbreak on tourists' real-time on-site emotional experience using geo-tagged check-in user-generated content data in China's National 5A scenic spots from November 7, 2019 to April 8, 2020. Results show that although the COVID-19 pandemic doesn't destroy the tourist attractions, tourists' real-time on-site emotional experience after the outbreak of COVID-19 is significantly lower than that of the period before the COVID-19 outbreak, suggesting that tourism destinations should not only focus on the recovery of tourist arrivals, but also pay attention to the tourist experience recovery during the tourism recovery stage. Results also provide empirical evidence and practical implications for destinations in tourist experience management during and after the COVID-19 pandemic.

Drug metabolite profiling utilizes liquid chromatography with tandem mass spectrometry (LC/MS/MS) to acquire ample information for metabolite identification and structural elucidation. However, there are still challenges in detecting and characterizing all potential metabolites that can be masked by a high biological background, especially the unknown and uncommon ones. In this work, a novel metabolite profiling workflow was established on a platform using a state-of-the-art tribrid high-resolution mass spectrometry (HRMS) system. Primarily, an instrumental method was developed based on the novel design of the tribrid system that facilitates in-depth MSn scans with two fragmentation devices. Additionally, different advanced data acquisition techniques were assessed and compared, and automatic background exclusion and deep-scan approaches were adopted to promote assay efficiency and metabolite coverage. Finally, different data-analysis techniques were explored to fully extract metabolite data from the information-rich MS/MS data sets. Overall, a workflow combining tribrid mass spectrometry and advanced acquisition methodology has been developed for metabolite characterization in drug discovery and development. It maximizes the tribrid HRMS platform's utility and enhances the coverage, efficiency, quality, and speed of metabolite profiling assays.

[Image: see text] IRAK4 is an attractive therapeutic target for the treatment of inflammatory conditions. Structure guided optimization of a nicotinamide series of inhibitors has been expanded to explore the IRAK4 front pocket. This has resulted in the identification of compounds such as 12 with improved potency and selectivity. Additionally 12 demonstrated activity in a pharmacokinetics/pharmacodynamics (PK/PD) model. Further optimization efforts led to the identification of the highly kinome selective 21, which demonstrated a robust PD effect and efficacy in a TLR7 driven model of murine psoriasis.

Lung carcinoma is the most prevalent malignancy in adults. Lidocaine (Lido) has been confirmed to exert an anti-tumor role in many human cancers. However, the role and underlying mechanism of Lido in lung carcinoma remain poorly understood. Cell proliferation ability, migration, invasion, and apoptosis were measured by Colony formation, 5-ethynyl-2'-deoxyuridine (EdU), Cell Counting Kit-8 (CCK-8), transwell, and flow cytometry assays. Circ_PDZD8, microRNA-516b-5p (miR-516b-5p), and Golgi transport 1A (GOLT1A) levels were detected by real-time quantitative polymerase chain reaction (RT-qPCR). Protein levels of proliferating cell nuclear antigen (PCNA) and GOLT1A were examined by western blot assay. The binding relationship between miR-516b-5p and circ_PDZD8 or GOLT1A was predicted by circular RNA Interactome or Starbase 3.0 and then verified by a dual-luciferase reporter assay. The biological roles of circ_PDZD8 and Lido on lung carcinoma cell growth were examined by the xenograft tumor model in vivo. Lido suppressed proliferation, migration, invasion, and induced apoptosis in lung carcinoma cells. Circ_PDZD8 and GOLT1A were increased, miR-516b-5p was decreased in lung carcinoma tissues and cell lines. Their expression presented the opposite trend in Lido-triggered lung carcinoma cells. Circ_PDZD8 might overturn the repression of Lido on cell growth ability and metastasis in this tumor. Mechanically, circ_PDZD8 might regulate GOLT1A expression by sponging miR-516b-5p. Circ_PDZD8 weakened the anti-lung carcinoma effect of Lido in vivo. Circ_PDZD8 might mitigate the inhibitory effect of Lido on tumor cell malignancy by modulating the miR-516b-5p/GOLT1A axis, providing a novel insight for lung carcinoma treatment.

The oxycyclohexyl acid BMS-986278 (

The diamondback moth, Plutella xylostella, is an important agricultural pest that severely damages cruciferous vegetables. Although previously considered a threat only to Brassica species, P. xylostella has been observed to feed on noncruciferous vegetables. Here, we established a population of P. xylostella on the pea Pisum sativum (PxP population). We compared this PxP population's performance on the pea host plant to a population (PxR) reared on the original host plant radish (Raphanus sativus) for several generations using an age‐stage, two‐sex life table and analyzed the correlations between different fitness parameters. In the 1st generation of the PxP population, survival rate of immature stage was 17%, while the survival rate of PxR was 68%; the duration of the 4th larval instar (5.30 d) and mortality (25%) of this generation were significantly longer (2.8 d) and higher (1%) than that of PxR, respectively (both p, We compared the performance of diamondback moth (Plutella xylostella) feeding on the original host plant radish (Raphanus sativus) and the marginal host plant pea (Pisum sativum). We found that the P. xylostella fitness was significantly improved upon long‐term acclimation on pea and the correlation between different fitness parameters was influenced by host plants.

Beim Textweltmodell rekonstruiert der Leser mit der Sprache die Konzeptualisierung zu den Sachverhalten. Im Rahmen der Konzeptualisierung steuern die emotionalen Komponenten masgeblich die mentale Reprasentation eines Sachverhalts (vgl. Schwarz-Friesel 22013: 213). In Abschnitt 4.1.2 wurde die emotive Bewertung erlautert.

Fur die Berichterstattung und Inszenierung ist nicht nur Text, sondern auch das Bild relevant – insbesondere auch zur Unterstutzung textuell erzeugter mentaler Bilder. Auch wenn es Ansatze gibt, Bilder verstarkt einzubinden (iconic turn), werden in der Linguistik mangels linguistischer Bildtheorien in erster Linie Bild- und Textbeziehungen untersucht (Diekmannshenke/Klemm/Stockl 2011; Stockl 2004; Gaede 1992). Verstarkt wird die Bedeutung des Bildes resp. die Beziehung zwischen Bild und Text in der Werbung betrachtet, da sie persuasive Strategien unterstutzen konnen (Fahrmann 2006; Janich 42005).

Am 12.08.2015 ereigneten sich im neuen Bezirk Binhai der chinesischen Stadt Tianjin, eine der vier Stadtstaaten Chinas, zwei schwere Explosionen in einem Lagerhaus fur Gefahrstoffguter. Laut dem chinesischen Staatsrat handelte es sich dabei um einen besonders grosen Arbeitsunfall bezuglich der Herstellungssicherheit. Die Explosionen fuhrten zu einem grosen Schaden: 165 Menschen verloren ihr Leben und der finanzielle Schaden belief sich insgesamt auf 6.866 Milliarden Ren Min Bi.

Introduction: BMS-986278 is being investigated as a treatment (tx) for idiopathic pulmonary fibrosis (IPF). In vitro studies demonstrated that OATP mediates human hepatic uptake of BMS-986278. Patients with IPF often receive concomitant medications, including OATPi. Aims and Objectives: To evaluate the effects of rifampin (rif) on the PK and tolerability of BMS-986278 in healthy adult participants (ppts). Methods: This was an open-label drug-interaction study. Fasted ppts received an oral dose of 30 mg BMS-986278 on d1 followed by a 7-d washout; on d8, ppts received an oral dose of 600 mg rif and 30 mg BMS-986278. Plasma PK was measured for BMS-986278 and rif; tolerability was monitored. Results: All 15 enrolled ppts completed the study (73% male, 73% white, mean [SD] age 46.1 [12.7] y and BMI 25.2 [2.7] kg/m2). Following coadministration with rif, BMS-986278 mean area under the curve from 0 to infinity (AUC0-inf) and maximum concentration (Cmax) were elevated by 3.13- and 2.75-fold, respectively, vs BMS-986278 alone. Median time to Cmax (Tmax) increased from 1.1 h (BMS-986278) to 2.0 h (BMS-986278+rif). Rif PK matched published data. BMS-986278+rif and BMS-986278 alone demonstrated a similar safety profile. Of 4 reported adverse events, 3 were mild (back pain, nausea, and presyncope) and 1 was moderate (constipation); none were deemed related to tx. Conclusions: BMS-986278+rif and BMS-986278 alone were generally well tolerated; increases in exposure up to 3x of BMS-986278 were observed with co-administration of rif. Concomitant OATPi medications anticipated to increase BMS-986278 exposure

Evolutionary and ecological forces are important factors that shape gut microbial profiles in hosts, which can help insects adapt to different environments through modulating their metabolites. However, little is known about how gut microbes and metabolites are altered when lepidopteran pest species switch hosts. In the present study, using 16S-rDNA sequencing and mass spectrometry-based metabolomics, we analyzed the gut microbiota and metabolites of three populations of Plutella xylostella: one feeding on radish (PxR) and two feeding on peas (PxP, with PxP-1 and PxP-17 being the first and 17th generations after host shift from radish to peas, respectively). We found that the diversity of gut microbes in PxP-17 was significantly lower than those in PxR and PxP-1, which indicates a distinct change in gut microbiota after host shift. Kyoto Encyclopedia of Genes and Genomes analysis revealed that the functions of energy metabolism, signal transduction, and xenobiotics biodegradation and metabolism were increased in PxP-17, suggesting their potential roles in host adaptation. Metabolic profiling showed a significant difference in the abundance of gut metabolites between PxR and PxP-17, and significant correlations of gut bacteria with gut metabolites. These findings shed light on the interaction among plants, herbivores, and symbionts, and advance our understanding of host adaptation associated with gut bacteria and metabolic activities in P. xylostella.

In the past 20 years, several novel data-mining methods, inclining mass defect filtering, background subtraction, isotope pattern filtering, and metabolomics analysis, have been developed and applied for drug metabolite profiling and identification by high-resolution mass spectrometry (HRMS). In addition, recently introduced HRMS-based data-dependent acquisition and data-independent acquisition methods, such as mass defect- and background exclusion-dependent acquisitions, MSE and SWATH, have greatly improved the speed and quality of biotransformation experiments carried out using HRMS. This chapter describes HRMS-based data acquisition and data-mining techniques for drug metabolite profiling and characterization and in silico tools for metabolite prediction and identification. Applicability of the HRMS technology to conducting common biotransformation experiments in support of drug discovery and development is also discussed with respect to special purposes and requirements of these experiments and unique advantages of individual HRMS techniques. Multiple real-life examples are included to demonstrate the usefulness of HRMS techniques in performing metabolite profiling and characterization experiments for lead optimization, selection of toxicology species for evaluating metabolite safety, and regulatory submission. Furthermore, current applications of HRMS-based technology in profiling and characterization of traditional Chinese medicine (TCM) components in samples from ADME studies of TCM in animals and humans are included.

In the present study, total membrane proteins from tumor cell lines including HepG2, Hep3B2, H226, Ovcar3 and N87 were extracted and digested with γLysC and trypsin. The resulting peptide lysate were pre-fractionated and subjected to untargeted quantitative proteomics analysis using a high resolution mass spectrometer. The mass spectra were processed by the MaxQuant and the protein abundances were estimated using total peak area (TPA) method. A total of 6037 proteins were identified, and the analysis resulted in the identification of 2647 membrane proteins. Of those, tumor antigens and absorption, metabolism, disposition and elimination (ADME) proteins including UDP-glucuronosyltransferase, cytochrome P450, solute carriers and ATP-binding cassette transporters were detected and disclosed significant variations among the cell lines. The principal component analysis was performed for the cluster of cell lines. The results demonstrated that H226 is closely related with N87, while Hep3B2 aligned with HepG2. The protein cluster of Ovcar3 was apart from that of other cell lines investigated. By providing for the first time quantitative untargeted proteomics analysis, the results delineated the expression profiles of membrane proteins. These findings provided a useful resource for selecting targets of choice for anticancer therapy through advancing data obtained from preclinical tumor cell line models to clinical outcomes., Graphical abstract Comparative untargeted proteomics analysis was conducted to identify and quantify membrane proteins in tumor cell lines through database searching with MaxQuant software. The identified proteins were annotated by gene ontology (GO) and assigned into four distinct subcellular categories. The proteomics analysis demonstrated significant variations among the tumor cell lines and lead to a greater appreciation for the role of membrane proteins in tumor development and drug resistance, and present targets of choice as tumor marker proteins.fx1

Mass spectrometry imaging (MSI) can visualize the composition, abundance, and spatial distribution of molecules in tissues or cells, which has been widely used in the research of life science. Insects, especially the agricultural pests, have received a great deal of interests from the scientists in biodiversity and food security. This review introduces the major characteristics of MSI, summarizes its application to the investigation of insect endogenous metabolites, exogenous metabolites, and the spatiotemporal changes of metabolites between insects and plants, and discusses its shortfalls and perspectives. The significance of these concerns is beneficial for future insect research such as physiology and metabolism.

Bruton’s tyrosine kinase (BTK), a non-receptor tyrosine kinase, is a member of the Tec family of kinases and is essential for B cell receptor (BCR) mediated signaling. BTK also plays a critical role in the downstream signaling pathways for the Fcγ receptor in monocytes, the Fce receptor in granulocytes, and the RANK receptor in osteoclasts. As a result, pharmacological inhibition of BTK is anticipated to provide an effective strategy for the clinical treatment of autoimmune diseases such as rheumatoid arthritis and lupus. This article will outline the evolution of our strategy to identify a covalent, irreversible inhibitor of BTK that has the intrinsic potency, selectivity, and pharmacokinetic properties necessary to provide a rapid rate of inactivation systemically following a very low dose. With excellent in vivo efficacy and a very desirable tolerability profile, 5a (branebrutinib, BMS-986195) has advanced into clinical studies.

Starting with the characteristics of WeChat, this paper analyzes the new problems that ideological and political work face. Relying on whole network, it is bound to reduce the contact between the teacher and student, which not only makes ideological educators lose their authority but also makes the ideological education lack the systematicness and regularity. Therefore, it is necessary to explore the contradiction of the above problems and come up with solutions. According to the morphological characteristics of WeChat education, this paper puts forward some methods and innovative ways of the ideological and political education, and points out that the emphasis of the two-way communication between teachers and students, and optimize dynamic education network mechanism linking online and offline.

PI3Kδ plays an important role controlling immune cell function and has therefore been identified as a potential target for the treatment of immunological disorders. This article highlights our work toward the identification of a potent, selective, and efficacious PI3Kδ inhibitor. Through careful SAR, the successful replacement of a polar pyrazole group by a simple chloro or trifluoromethyl group led to improved Caco-2 permeability, reduced Caco-2 efflux, reduced hERG PC activity, and increased selectivity profile while maintaining potency in the CD69 hWB assay. The optimization of the aryl substitution then identified a 4′-CN group that improved the human/rodent correlation in microsomal metabolic stability. Our lead molecule is very potent in PK/PD assays and highly efficacious in a mouse collagen-induced arthritis model.

Selective PI3Kδ inhibitors have recently been hypothesized to be appropriate immunosuppressive agents for the treatment of immunological disorders such as rheumatoid arthritis. However, few reports have highlighted molecules that are highly selective for PI3Kδ over the other PI3K isoforms. In this letter, isoform and kinome selective PI3Kδ inhibitors are presented. The Structural Activity Relationship leading to such molecules is outlined.

Investigation of various heterocyclic core isosteres of imidazopyrazines 1 & 2 yielded purine derivatives 3 & 8 as potent and selective BTK inhibitors. Subsequent SAR studies of the purine series led to the discovery of 20 as a leading compound. Compound 20 is very selective when screened against a panel of 400 kinases and is a potent inhibitor in cellular assays of human B cell function including B-Cell proliferation and CD86 cell surface expression and exhibited in vivo efficacy in a mouse PCA model. Its X-ray co-crystal structure with BTK shows that the high selectivity is gained from filling a BTK specific lipophilic pocket. However, physical and ADME properties leading to low oral exposure hindered further development.

Ticlopidine, an antiplatelet drug, undergoes extensive oxidative metabolism to form S-oxide, N-oxide, hydroxylated and dealkylated metabolites. However, metabolism of ticlopidine via conjugation has not been thoroughly investigated. In this study, multiple data acquisition and processing tools were applied to the detection and characterization of ticlopidine conjugates in rat bile. Accurate full-scan mass spectrometry (MS) and collision-induced dissociation (CID) MS/MS data sets were recorded using isotope pattern-dependent acquisition on an LTQ/Orbitrap system. In addition, mass spectral data from online H/D exchanging and high collision energy dissociation (HCD) were recorded. Data processes were carried out using extracted ion chromatography (EIC), mass defect filter (MDF) and isotope pattern filter (IPF). The total ion chromatogram displayed a few major conjugated metabolites and many endogenous components. Profiles from EIC and IPF processes exhibited multiple conjugates with no or minimal false positives. However, ticlopidine conjugates that were not predictable or lost a chorine atom were not found by EIC or IPF, respectively. MDF was able to detect almost all of ticlopidine conjugates although it led to a few more false positives. In addition to CID spectra, data from HCD, H/D exchanging experiments and isotope pattern simulation facilitated structural characterization of unknown conjugates. Consequently, 20 significant ticlopidine conjugates, including glucuronide, glutathione, cysteinylglycine, cysteine and N-acetylcysteine conjugates, were identified in rat bile, a majority of which are associated with bioactivation and not previously reported. This study demonstrates the utility and limitation of various high-resolution MS-based data acquisition and processing techniques in detection and characterization of conjugated metabolites. Copyright © 2013 John Wiley & Sons, Ltd.

Local anesthetic infiltration has been used to manage postoperative pain in various surgeries. The present study was aimed to investigate the effect of skin infiltration with 0.5 % ropivacaine on postoperative pain in patients undergoing craniotomy. One hundred and six patients with ASA I/II scheduled to undergo elective craniotomy were enrolled during March to November in 2015 in this prospective, randomized, placebo-controlled, double-blind study. After the anesthesia induction, skin along the incision was infiltrated with 0.5 % ropicavaine (group R, n = 53) or 0.9 % normal saline (group C, n = 53), respectively. Morphine was used as rescue analgesic postoperatively. Morphine consumption during the first 24 postoperative hours was recorded as the primary outcome, and the time to first rescue requirement was also recorded. Pain was assessed at 2, 4, 8, 24 h, 7 days, 3 months after surgery by visual analog scale (VAS). Heart rate and mean arterial pressure were recorded before anesthesia induction (T1), after anesthesia induction (T2), after scalp infiltration (T3), during skull drilling (T4), mater cutting (T5) and skin closure (T6). Morphine consumption during the first 24 postoperative hours was significantly higher in group C than in group R (13.36 [6.5, 20] vs. 6.3 [0, 10] mg, P

Currently, mass spectrometry-based protein bioanalysis is primarily achieved through monitoring the representative peptide(s) resulting from analyte protein digestion. However, this approach is often incapable of differentiating the measurement of protein analyte from its post-translational modifications (PTMs) and/or potential biotransformation (BTX) products. This disadvantage can be overcome by direct measurement of the intact protein analytes. Selected reaction monitoring (SRM) on triple quadrupole mass spectrometers has been used for the direct measurement of intact protein. However, the fragmentation efficiency though the SRM process could be limited in many cases, especially for high molecular weight proteins. In this study, we present a new strategy of intact protein bioanalysis by high-resolution (HR) full scan mass spectrometry using human lysozyme as a model protein. An HR linear ion-trap/Orbitrap mass spectrometer was used for detection. A composite of isotopic peaks from one or multiple charge states can be isolated from the background and used to improve the signal-to-noise ratio. The acquired data were processed by summing extracted ion chromatograms (EIC) of the 10 most intense isotopic ions of octuply protonated lysozyme. Quantitation of the plasma lysozyme was conducted by utilizing high resolving power and an EIC window fitting to the protein molecular weight. An assay with a linear dynamic range from 0.5 to 500 μg/mL was developed with good accuracy and precision. The assay was successfully employed for monitoring the level of endogenous lysozyme and a potential PTM in human plasma. The current instrumentation limitations and potential advantages of this approach for the bioanalysis of large proteins are discussed.

A new strategy using a hybrid linear ion trap/Orbitrap mass spectrometer and multiple post-acquisition data mining techniques was evaluated and applied to the detection and characterization of in vitro metabolites of indinavir. Accurate-mass, full-scan MS and MS/MS data sets were acquired with a generic data-dependent method and processed with extracted-ion chromatography (EIC), mass-defect filter (MDF), product-ion filter (PIF), and neutral-loss filter (NLF) techniques. The high-resolution EIC process was shown to be highly effective in the detection of common metabolites with predicted molecular weights. The MDF process, which searched for metabolites based on the similarity of mass defects of metabolites to those of indinavir and its core substructures, was able to find uncommon metabolites not detected by the EIC processing. The high-resolution PIF and NLF processes selectively detected metabolites that underwent fragmentation pathways similar to those of indinavir or its known metabolites. As a result, a total of 15 metabolites including two new indinavir metabolites were detected and characterized in a rat liver S9 incubation sample. Overall, these data mining techniques, which employed distinct metabolite search mechanisms, were complementary and effective in detecting both common and uncommon metabolites. In summary, the results demonstrated that this analytical strategy enables the high-throughput acquisition of accurate-mass LC/MS data sets, comprehensive search of a variety of metabolites through the post-acquisition processes, and effective structural characterization based on elemental compositions of metabolite molecules and their product ions.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants found in car exhausts, charbroiled food, and tobacco smoke. Three pathways for the metabolic activation of B[a]P to ultimate carcinogens have been proposed. The most widely accepted pathway involves cytochrome-P450 (CYP) 1A1- and/or 1B1-mediated formation of B[a]P-7,8-oxide, which undergoes epoxide hydrolase-mediated metabolism to the proximate carcinogen B[a]P-7,8-dihydro-7,8-diol. Further CYP1A1- and/or CYP1B1-mediated activation of the dihydrodiol results in the formation of 7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (B[a]PDE), the ultimate carcinogen. In previous studies, it was demonstrated that (+)-anti-B[a]PDE was the most potent tumorigen of the CYP-derived B[a]PDE diastereomers. We have developed a stable isotope dilution, liquid chromatography multiple reaction monitoring/mass spectrometry (LC-MRM/MS) assay for all eight (±)-anti-B[a]PDE-derived dGuo and dAdo DNA-adducts. The LC-MRM/MS assay was rigorously validated and used to show that (+)-anti-trans-B[a]PDE-dGuo was the major adduct formed when naked DNA and human bronchoalveolar adenocarcinoma H358 cells were treated with (±)-anti-B[a]PDE. The preference for DNA-adducts derived from (+)-anti-B[a]PDE was even more apparent in cellular DNA. Thus, the increased potency of (+)-anti-B[a]PDE as a tumorigen is most likely due its ability to preferentially form DNA-adducts when compared with (−)-anti-B[a]PDE. Also, the adduct profile suggests that this occurs by binding of (+)-anti-B[a]PDE to DNA in a manner that facilitates covalent binding to dGuo rather than dAdo residues. Copyright © 2006 John Wiley & Sons, Ltd.

In the production of recombinant proteins by the insect cell–baculovirus process, fresh medium renewal prior to virus infection has been an effective measure for maintaining high protein yields. The spent medium used in the growth stage may still be unexhausted and can be reused for cell growth. In this study, we exercised the recycle of a spent insect cell medium for cell growth and recombinant protein production. It was found that the spent medium collected from a culture close to the stationary growth phase could provide full support for insect cell growth through another batch culture after fortified with suitable nutrients (yeastolate, glucose and glutamine) and a small fraction (15–20%) of fresh medium. The specific and volumetric protein yields with cells grown in the recycled spent medium were in most cases similar to those with cells grown in fresh medium. Protein yields on per unit volume of fresh medium in the process incorporating spent medium recycle compared favourably with that achieved in a batch or fed-batch process. Spent medium recycle is hence a feasible alternative for the insect cell culture–baculovirus process.

A number of medium additives such as Pluronic F68, methylcellulose, and serum have been shown to decrease the adhesion of animal cells to air bubbles, thus reducing cell damage by the bubbles at rupture. The effect may be associated with the interactions between the additives and the cells. One possible mechanism is that the additives adsorb to the cell membrane through a hydrophobic interaction, resulting in decreased hydrophobicity of the cell surface. This consequently reduces cell adhesion to gas bubbles. To test this hypothesis, we measured the hydrophobicity (adhesion to a hydrocarbon) of two insect cell lines in the presence of medium additives including Pluronic F68, methylcellulose, polyethylene glycol (PEG), and fetal bovine serum. All these additives except PEG caused substantial reduction in cell surface hydrophobicity which was consistent with their effect of decreasing cell adhesion to gas bubbles. In addition, significant adsorption was detected for the nonionic surfactants Pluronic and PEG to the insect cells. The findings are very helpful for elucidating the mechanisms of animal cell protection by surface-active chemicals.