Detection and Quantification of Mono-Rhamnolipids and Di-Rhamnolipids Produced by Pseudomonas aeruginosa

The environmental bacterium Pseudomonas aeruginosa is an opportunistic pathogen with high antibiotic resistance that represents a health hazard. This bacterium produces high levels of biosurfactants known as rhamnolipids (RL), which are molecules with significant biotechnological value but are also associated with virulence traits. In this respect, the detection and quantification of RL may be useful for both biotechnology applications and biomedical research projects. In this article, we demonstrate step-by-step the technique to detect the production of the two forms of RL produced by P. aeruginosa using thin-layer chromatography (TLC): mono-rhamnolipids (mRL), molecules constituted by a dimer of fatty acids (mainly C10-C10) linked to one rhamnose moiety, and di-rhamnolipids (dRL), molecules constituted by a similar fatty acid dimer linked to two rhamnose moieties. Additionally, we present a method to measure the total amount of RL based on the acid hydrolysis of these biosurfactants extracted from a P. aeruginosa culture supernatant and the subsequent detection of the concentration of rhamnose that reacts with orcinol. The combination of both techniques can be used to estimate the approximate concentration of mRL and dRL produced by a specific strain, as exemplified here with the type strains PAO1 (phylogroup 1), PA14 (phylogroup 2), and PA7 (phylogroup 3).

Solvent-free synthesis of hydrophobic and amphiphilic esters using a chemically modified lipase from Thermomyces lanuginosus: a comparative study with native and immobilized forms

Using lipases to catalyze the synthesis of the most differentiated type of compounds remains one of the major challenges among scientists. Seeking more economic and advantageous catalysts is a current goal of green chemistry. In this work, we demonstrate the potential of a chemically modified form of lipase from Thermomyces lanuginosus (cmLTL) for the synthesis of both hydrophobic (heptyl heptanoate, heptyl octanoate, heptyl decanoate, decyl heptanoate, decyl octanoate and decyl decanoate) and amphiphilic (2-(2-ethoxyethoxy)ethyl oleate and 2-(2-ethoxyethoxy)ethyl linoleate) esters, in bulk. The results were compared with its native (LTL) and immobilized (imLTL) forms. The data revealed that LTL showed poor activity for all reactions performed with n-heptane (η<20 %). ImLTL was able to synthesize all hydrophobic esters (η>60 %), with exception of the short ester, heptyl heptanoate. cmLTL was the only form of LTL capable of producing hydrophobic and amphiphilic esters, without compromising the yield when the reactions were performed under solvent-free conditions (>50 %). Molecular modeling showed that the active pocket of cmLTL is able to deeply internalize transcutol, with stronger interactions, justifying the outstanding results obtained. Furthermore, owing to the possibility of cmLTL filtration, the reusability of the catalyst is ensured for at least 6 cycles, without compromising the reaction yields.

High mono-rhamnolipids production by a novel isolate Pseudomonas aeruginosa LP20 from oily sludge: characterization, optimization, and potential application

This study aims to isolate microbial strains for producing mono-rhamnolipids with high proportion. Oily sludge is rich in petroleum and contains diverse biosurfactant-producing strains. A biosurfactant-producing strain LP20 was isolated from oily sludge, identified as Pseudomonas aeruginosa based on phylogenetic analysis of 16S rRNA. High-performance liquid chromatography-mass spectrometry results indicated that biosurfactants produced from LP20 were rhamnolipids, mainly containing Rha-C8-C10, Rha-C10-C10, Rha-Rha-C8-C10, Rha-Rha-C10-C10, Rha-C10-C12:1, and Rha-C10-C12. Interestingly, more mono-rhamnolipids were produced by strain LP20 with a relative abundance of 64.5%. Pseudomonas aeruginosa LP20 optimally produced rhamnolipids at a pH of 7.0 and a salinity of 0.1% using glycerol and nitrate. The culture medium for rhamnolipids by strain LP20 was optimized by response surface methodology. LP20 produced rhamnolipids up to 6.9 g L-1, increased by 116%. Rhamnolipids produced from LP20 decreased the water surface tension to 28.1 mN m-1 with a critical micelle concentration of 60 mg L-1. The produced rhamnolipids emulsified many hydrocarbons with EI24 values higher than 56% and showed antimicrobial activity against Staphylococcus aureus and Cladosporium sp. with inhibition rates 48.5% and 17.9%, respectively. Pseudomonas aeruginosa LP20 produced more proportion of mono-rhamnolipids, and the LP20 rhamnolipids exhibited favorable activities and promising potential in microbial-enhanced oil recovery, bioremediation, and agricultural biocontrol.

Innovative Detection of Testosterone Esters in Camel Hair: Unravelling the Mysteries of Dromedary Endocrinology

Introduction: Doping and steroid use represent a serious threat to animal health and can even lead to their untimely and painful death. However, doping is an acute problem in today's animal racing world, particularly in camel racing. Testosterone and its ten esters (benzoate, valerate, isocaproate, hexahydrobenzoate, decanoate, undecanoate, laurate, enanthate, cypionate, and caproate) are of utmost importance, because when they are administered to animals it is difficult to measure them efficiently. The levels of testosterone and its esters in camels and other animals are typically determined using urine and blood tests. The aim of this study was to develop and validate a liquid chromatographic-mass spectrometric (LC-MS/MS) method to determine testosterone esters in camel hair, and to apply the validated method to determine testosterone esters in collected samples. To our knowledge, this is the first report of such research. Results and Discussion: The levels of testosterone and its ten derivatives, along with the cortisol-D4 internal standard, were optimised for LC-MS/MS analysis; however, only testosterone along with its seven esters (namely benzoate, valerate, isocaproate, hexahydrobenzoate, decanoate, undecanoate and laurate) could be validated in camel hair. Only five testosterone esters could be determined in camel hair samples; the concentrations were obtained as 10.5-14.9 pg/mg for valerate (in three camels), 12.5-151.6 pg/mg for hexahydrobenzoate (in six camels), 4.8-32.1 pg/mg for laurate (in five camels), 5.1 pg/mg decanoate (in one camel), and 8.35-169 pg/mg for testosterone (in all 24 camels). Interestingly, the three racing camels displayed high concentrations of testosterone (59.2-169 pg/mg, all three camels), laurate (4.8-14.5 pg/mg, two camels), hexahydrobenzoate (116 pg/mg, one camel), decanoate (5.1 pg/mg, one camel), and valerate (11.7 pg/mg, one camel). Methods: Camel hair samples were collected from 21 non-racing dromedary camels along with three racing camels in Al Ain, UAE; these were decontaminated, pulverised, sonicated, and extracted prior to analysis. An LC-MS/MS method was employed to determine the levels of testosterone esters in the hair samples. Conclusions: This novel camel-hair test procedure is accurate, sensitive, rapid, and robust. The findings reported in this study could be significant to evaluate racing camels for suspected doping offenses. Further controlled testosterone supplementation studies are required to evaluate individual esters' effects on camel health and diseases and on performance enhancement levels. This new hair test could promote further studies in doping control, toxicology, and pharmacology, as well as having other clinical applications relating to camel health, injury, and disease.

Effect of static tensile stress on enzymatic degradation of poly(glycerol sebacate)

Poly(glycerol sebacate) (PGS) is an excellent scaffold material in tissue engineering due to good biocompatibility and tunable mechanical properties. The degradation properties of PGS have been primarily explored in static phosphate buffer solution or enzyme solution. It is vital to understand how the tensile stress affect the degradation rate. In this study, PGS was synthetized by melt polycondensation and its properties were characterized. Then an in vitro degradation device which could provide different constant tensile stresses was carefully designed and established, and the enzymatic degradation of PGS was tested under 0-150 kPa at 37°C. It was found that holes of PGS surface arranged almost parallel to each other and perpendicular to the direction of tensile stresses at 100 kPa and 150 kPa after 2-4 days degradation. After 8 days degradation, the ultimate tensile strength (UTS) of PGS at 150 kPa was 0.28 MPa and the elastic modulus was 1.11 MPa, while the UTS of PGS was 0.44 MPa and the elastic modulus was 1.63 MPa before degradation, both of them have significant differences. Hence, the tensile stress and degradation time were proportional to the appear time and size of holes, leading to the decrease of mass loss, UTS and elastic modulus. The relationship between stress and PGS degradation rates was quantitatively described through our degradation experiments, providing guidance for suitable PGS applications in the future.

Bioconversion and P-gp-Mediated Transport of Depot Fluphenazine Prodrugs after Intramuscular Injection

Fluphenazine (FPZ) decanoate, an ester-type prodrug formulated as a long-acting injection (LAI), is used in the treatment of schizophrenia. FPZ enanthate was also developed as an LAI formulation, but is no longer in use clinically because of the short elimination half-life of FPZ, the parent drug, after intramuscular injection. In the present study, the hydrolysis of FPZ prodrugs was evaluated in human plasma and liver to clarify the reason for this difference in elimination half-lives. FPZ prodrugs were hydrolyzed in human plasma and liver microsomes. The rate of hydrolysis of FPZ enanthate in human plasma and liver microsomes was 15-fold and 6-fold, respectively, faster than that of FPZ decanoate. Butyrylcholinesterase (BChE) and human serum albumin (HSA) present in human plasma, and two carboxylesterase (CES) isozymes, hCE1 and hCE2, expressed in ubiquitous organs including liver, were mainly responsible for the hydrolysis of FPZ prodrugs. FPZ prodrugs may not be bioconverted in human skeletal muscle at the injection site because of lack of expression of BChE and CESs in muscle. Interestingly, although FPZ was a poor substrate for human P-glycoprotein, FPZ caproate was a good substrate. In conclusion, it is suggested that the shorter elimination half-life of FPZ following administration of FPZ enanthate compared with FPZ decanoate can be attributed to the more rapid hydrolysis of FPZ enanthate by BChE, HSA and CESs.

The toxic effects of anabolic steroids "nandrolone decanoate" on cardiac and skeletal muscles with the potential ameliorative effects of silymarin and fenugreek seeds extract in adult male albino rats

BACKGROUND

Anabolic steroids (AS) are commonly abused by body builders and athletes aiming to increase their strength and muscle mass but unfortunately, the long-term use of AS may lead to serious side effects. Nandrolone Decanoate is one of the Class II anabolic androgenic steroids which quickly spread globally and used clinically and illicitly. Our research was directed to assess the toxic effects of anabolic steroids on cardiac and skeletal muscles in male albino rats and to evaluate the potential ameliorative effects of fenugreek seeds extract and silymarin.

METHODS

Our research was done on 120 male albino rats that were allocated into 6 groups; group I: Served as a control group, group II: Received the anabolic steroid Nandrolone Decanoate, group III: Received silymarin orally, group IV: Received fenugreek seeds extract orally, group (V): Received the anabolic steroid Nandrolone Decanoate and silymarin and group (VI): Received the anabolic steroid Nandrolone Decanoate and fenugreek seeds extract. By the end of the study, rats were sacrificed, and blood samples were collected for biochemical analysis and autopsy samples for histopathological examination.

RESULTS

The anabolic steroids toxic effects on rats showed a significant decrease in serum High Density Lipoprotein (HDL) level and increase in cholesterol, triglycerides, and Low-Density Lipoprotein (LDL) levels. There was a significant elevation in cardiac troponin I level. As regards to histopathological examination of the cardiac and skeletal muscles, the study showed marked degenerative changes and necrosis. Both silymarin and fenugreek seeds extract provided a protective effect on the biochemical and histopathological changes. The antioxidant effects of silymarin and fenugreek seeds extract were evaluated on the heart, skeletal muscles and showed that, the tissue levels of Superoxide dismutase (SOD), Catalase and reduced glutathione (GSH) decreased in AS treated rats compared to the control group. On the other hand, the tissue Malondialdehyde (MDA) levels were elevated.

CONCLUSIONS

Anabolic steroids have a toxic effect on the cardiac and skeletal muscles of albino rats with improvement by treatment with fenugreek seeds extract and silymarin.

Beta-Hydroxybutyrate (BHB), Glucose, Insulin, Octanoate (C8), and Decanoate (C10) Responses to a Medium-Chain Triglyceride (MCT) Oil with and without Glucose: A Single-Center Study in Healthy Adults

MCTs are increasingly being used to promote ketogenesis by patients on ketogenic diet therapy, but also by people with other conditions and by the general public for the perceived potential benefits. However, consumption of carbohydrates with MCTs and untoward gastrointestinal side effects, especially at higher doses, could decrease the sustainability of the ketogenic response. This single-center study investigated the impact of consuming carbohydrate as glucose with MCT oil compared to MCT alone on the BHB response. The effects of MCT oil versus MCT oil plus glucose on blood glucose, insulin response, levels of C8, C10, BHB, and cognitive function were determined, and side effects were monitored. A significant plasma BHB increase with a peak at 60 min was observed in 19 healthy participants (24.4 ± 3.9 years) after consuming MCT oil alone, and a more delayed but slightly higher peak was observed after consuming MCT oil plus glucose. A significant increase in blood glucose and insulin levels occurred only after MCT oil plus glucose intake. The overall mean plasma levels of C8 and C10 were higher with the intake of MCT oil alone. MCT oil plus glucose consumption showed improved scores for the arithmetic and vocabulary subtests.

Enhanced Bioactivity of Tailor-Made Glycolipid Enriched Manuka Honey

Glycolipids can be synthetized in deep eutectic solvents (DESs) as they possess low water content allowing a reversed lipase activity and thus enables ester formation. Based on this principle, honey can also serve as a media for glycolipid synthesis. Indeed, this supersaturated sugar solution is comparable in terms of physicochemical properties to the sugar-based DESs. Honey-based products being commercially available for therapeutic applications, it appears interesting to enhance its bioactivity. In the current work, we investigate if enriching medical grade honey with in situ enzymatically-synthetized glycolipids can improve the antimicrobial property of the mixture. The tested mixtures are composed of Manuka honey that is enriched with octanoate, decanoate, laurate, and myristate sugar esters, respectively dubbed GOH, GDH, GLH, and GMH. To characterize the bioactivity of those mixtures, first a qualitative screening using an agar well diffusion assay has been performed with methicillin-resistant Staphylococcus aureus, Bacillus subtilis, Candida bombicola, Escherichia coli, and Pseudomonas putida which confirmed considerably enhanced susceptibility of these micro-organisms to the different glycolipid enriched honey mixtures. Then, a designed biosensor E. coli strain that displays a stress reporter system consisting of three stress-specific inducible, red, green, and blue fluorescent proteins which respectively translate to physiological stress, genotoxicity, and cytotoxicity was used. Bioactivity was, therefore, characterized, and a six-fold enhancement of the physiological stress that was caused by GOH compared to regular Manuka honey at a 1.6% (v/v) concentration was observed. An antibacterial agar well diffusion assay with E. coli was performed as well and demonstrated an improved inhibitory potential with GOH upon 20% (v/v) concentration.

Antibacterial Conductive UV-Blocking Adhesion Hydrogel Dressing with Mild On-Demand Removability Accelerated Drug-Resistant Bacteria-Infected Wound Healing

The on-demand replacement of multifunctional hydrogel wound dressings helps to avoid bacterial colonization, and the on-demand painless peeling of tissue adhesive hydrogels on the wound site remains a major challenge to be solved. In this work, we design and develop a series of multifunctional dynamic Schiff base network hydrogels composed of cystamine-modified hyaluronic acid, benzaldehyde-functionalized poly(ethylene glycol)-co-poly(glycerol sebacate), and polydopamine@polypyrrole nanocomposite (PDA@PPy) with mild on-demand removability to enhance drug-resistant bacteria-infected wound healing. These hydrogels exhibited ideal injectable and self-healing properties, excellent tissue adhesion, in vivo hemostasis, good antioxidation, and conductivity. PDA@PPy inspired by melanin endows hydrogels with excellent antioxidant capacity, UV-blocking ability, and photothermal anti-infection ability. Based on the dynamic oxidation-reduction response of disulfide bonds inspired by the dissociation of the tertiary spatial structure transformation of poly-polypeptide chains, these hydrogels can achieve rapid painless on-demand removal under mild conditions by adding dithiothreitol. These multifunctional hydrogels significantly promoted collagen deposition and angiogenesis in the MRSA-infected full-thickness skin repair experiment. All the results showed that these multifunctional hydrogels with painless on-demand removal property showed great potential in clinical treatment of infected wounds.

A Route to Lipid ALC-0315: a Key Component of a COVID-19 mRNA Vaccine

This paper describes a synthesis of ALC-0315 by a sequence that more than doubles the overall yield relative to the published one, and that employs much cleaner reactions, thereby facilitating purifications to a considerable extent.

Lipid nanoparticle-mediated lymph node-targeting delivery of mRNA cancer vaccine elicits robust CD8+ T cell response

The targeted delivery of messenger RNA (mRNA) to desired organs remains a great challenge for in vivo applications of mRNA technology. For mRNA vaccines, the targeted delivery to the lymph node (LN) is predicted to reduce side effects and increase the immune response. In this study, we explored an endogenously LN-targeting lipid nanoparticle (LNP) without the modification of any active targeting ligands for developing an mRNA cancer vaccine. The LNP named 113-O12B showed increased and specific expression in the LN compared with LNP formulated with ALC-0315, a synthetic lipid used in the COVID-19 vaccine Comirnaty. The targeted delivery of mRNA to the LN increased the CD8+ T cell response to the encoded full-length ovalbumin (OVA) model antigen. As a result, the protective and therapeutic effect of the OVA-encoding mRNA vaccine on the OVA-antigen-bearing B16F10 melanoma model was also improved. Moreover, 113-O12B encapsulated with TRP-2 peptide (TRP2180-188)-encoding mRNA also exhibited excellent tumor inhibition, with the complete response of 40% in the regular B16F10 tumor model when combined with anti-programmed death-1 (PD-1) therapy, revealing broad application of 113-O12B from protein to peptide antigens. All the treated mice showed long-term immune memory, hindering the occurrence of tumor metastatic nodules in the lung in the rechallenging experiments that followed. The enhanced antitumor efficacy of the LN-targeting LNP system shows great potential as a universal platform for the next generation of mRNA vaccines.

Introducing a bio sorbent for removal of methylene blue dye based on flexible poly(glycerol sebacate)/chitosan/graphene oxide ecofriendly nanocomposites

As a consequence of industrial activities, one of the most prevalent components in wastewater is Water-soluble dyes needed to be removed. In this research, eco-friendly adsorbents based on poly(glycerol sebacate) (PGS), including PGS-graphene oxide nanoparticles (GO), PGS-graft-chitosan(CS), and PGS-CS-GO nanocomposites, have been proposed as efficient dye adsorbents for the wastewater treatment procedure. FESEM images showed that a smooth and uniform structure was created over incorporating CS into PGS. Besides, the presence of CS within PGS/GO nanocomposites had a positive impact on the exfoliation of GO. Moreover, it was found that the incorporation of both CS and GO into PGS reduced the glass transition of PGS. Besides, their coexistence can probably increase the chain regularity in the polymer matrix and cause a relatively larger crystal size of PGS. In this regard, the ternary nanocomposite saw a Tg value of -29.4 °C. A high adsorption capacity of 178 mg g^-1, as well as 99 removal% efficiency, were observed in the case of the PGS-CS-GO sample after 300 min at a dye concentration of 100 mg L^-1 and pH 7. Additionally, the adsorption capacity value of the adsorbent was preserved around 129 mg g^-1 after 7 cycles of adsorption-desorption. The findings revealed that innovatively synthesized PGS-g-CS/GO nanocomposites could efficiently remove methylene blue from water solutions. Hence, they can be used as a powerful and influential dye adsorbent to purify water solutions.

A Bilayered, Electrospun Poly(Glycerol-Sebacate)/Polyurethane-Polyurethane Scaffold for Engineering of Endothelial Basement Membrane

In the cardiovascular system, heart valves and vessels are subjected to continuous cyclic mechanical loadings due to the pulsatile nature of blood flow. Hence, in leveraging tissue engineering (TE) strategies to regenerate such a system, the candidate scaffold should not only be biocompatible with the desired biodegradation rate, but it should also be mechanically competent to provide a supportive structure for facilitating stem cells retention, growth, and differentiation. To this end, herein, we introduced a novel scaffold composed of poly(glycerol-sebacate) (PGS) and polyurethane (PU), which comprises of two layers: an electrospun pure PU layer beneath another electrospun PGS/PU layer with a different ratio of PGS to PU (3:2, 1:1, 2:3 Wt:Wt). The electrospun PGS/PU-PU scaffold was mechanically competent and showed intended hydrophilicity and a good biodegradation rate. Moreover, the PGS/PU-PU scaffold indicated cell viability and proliferation within ten days of in vitro cell culture and upon 7 day vascular endothelial growth factor (VEGF) stimulation, supported endothelial differentiation of mesenchymal stem cells by significant overexpression of platelet-endothelial cell adhesion molecule-1, von Willebrand factor, and VEGF receptor 2. The results of this study could be implemented in cardiovascular TE strategies when regeneration of blood vessel or heart valve is desired.

Surface Plasmon Resonance Monitoring of Mono-Rhamnolipid Interaction with Phospholipid-Based Liposomes

The interactions of mono-rhamnolipids (mono-RLs) with model membranes were investigated through a biomimetic approach using phospholipid-based liposomes immobilized on a gold substrate and also by the multiparametric surface plasmon resonance (MP-SPR) technique. Biotinylated liposomes were bound onto an SPR gold chip surface coated with a streptavidin layer. The resulting MP-SPR signal proved the efficient binding of the liposomes. The thickness of the liposome layer calculated by modeling the MP-SPR signal was about 80 nm, which matched the average diameter of the liposomes. The mono-RL binding to the film of the phospholipid liposomes was monitored by SPR and the morphological changes of the liposome layer were assessed by modeling the SPR signal. We demonstrated the capacity of the MP-SPR technique to characterize the different steps of the liposome architecture evolution, i.e., from a monolayer of phospholipid liposomes to a single phospholipid bilayer induced by the interaction with mono-RLs. Further washing treatment with Triton X-100 detergent left a monolayer of phospholipid on the surface. As a possible practical application, our method based on a biomimetic membrane coupled to an SPR measurement proved to be a robust and sensitive analytical tool for the detection of mono-RLs with a limit of detection of 2 μg mL^-1.

Enhanced production of mono-rhamnolipid in Pseudomonas aeruginosa and application potential in agriculture and petroleum industry

Differences in the rhamnolipid structures must result in its different activities, thus affecting its application effect. The rhlC gene in Pseudomonas aeruginosa SG was knocked out to construct strain P. aeruginosa SGΔrhlC. Rhamnolipid production was enhanced by 23.3% through knocking out rhlC gene. P. aeruginosa SGΔrhlC produced 14.22 g/L of rhamnolipid using glycerol and nitrate. Five kinds of mono-rhamnolipid but no di-rhamnolipid were produced by strain SGΔrhlC. The main rhamnolipid homologues were Rha-C₁₀-C₁₀, Rha-C₁₀-C_12:1 and Rha-C₁₀-C₁₂. Mono-rhamnolipid exhibited better antimicrobial activity to Escherichia coli, Staphylococcus aureus, Aspergillus niger and Penicillium chrysogenum. Rhamnolipid produced from strain SGΔrhlC showed greater emulsifying activity to crude oil with EI₂₄ of 84.73%. Rhamnolipid produced from strain SGΔrhlC efficiently washed oily sludge at 35 °C. High-producing strain P. aeruginosa SGΔrhlC and its produced mono-rhamnolipid are more promising in agriculture and petroleum industry. This study is a step forward to the tailor-made biosynthesis and application of rhamnolipid.

Slow degrading poly(glycerol sebacate) derivatives improve vascular graft remodeling in a rat carotid artery interposition model

Porous synthetic grafts made of poly (glycerol sebacate) (PGS) can transform into autologous vascular conduits in vivo upon degradation of PGS. A long-held doctrine in tissue engineering is the necessity to match degradation of the scaffolds to tissue regeneration. Here, we tested the impact of degradation of PGS and its derivative in an interposition model of rat common carotid artery (CCA). Previous work indicates a complete degradation of PGS within approximately 2 weeks, likely at the fast end of the spectrum. Thus, the derivation of PGS focuses on delay degradation by conjugating the free hydroxy groups in PGS with a long chain carboxylic acid: palmitic acid, one of the most common lipid components. We evaluated two of the resultant palmitate-PGS (PPGS) in this study: one containing 9% palmitate (9-PPGS) and the other16% palmitate (16-PPGS). 16-PPGS grafts had the highest patency. Ultrasound imaging showed that the lumens of 16-PPGS grafts were similar to CCA and smaller than 9-PPGS and PGS grafts 12 weeks post-operation. Immunohistological and histological examination showed an endothelialized lumens in all three types of grafts within 4 weeks. Inflammatory responses to 16-PPGS grafts were limited to the adventitial space in contrast to a more diffusive infiltration in 9-PPGS and PGS grafts in week 4. Examination of calponin+ and αSMA+ cells revealed that 16-PPGS grafts remodeled into a distinctive bi-layered wall, while the walls of 9-PPGS grafts and PGS grafts only had one thick layer of smooth muscle-like cells. Correspondingly, the expression of collagen III and elastin displayed an identical layered structure in the remodeled 16-PPGS grafts, in contrast to a more spread distribution in 9-PPGS and PGS grafts. All the three types of grafts exhibited the same collagen content and burst pressure after 12 weeks of host remodeling. However, the compliance and elastin content of 16-PPGS grafts in week 12 were closest to those of CCA. Overall, placing the degradation of PGS derived elastomer to a window of 4-12 weeks results in vascular conduits closer to arteries in a rat carotid artery interposition model over a 12-week observation period.

Magnesium-based biodegradable microelectrodes for neural recording

This article reports fabrication, characterization, degradation and electrical properties of biodegradable magnesium (Mg) microwires coated with two functional polymers, and the first in vivo evidence on the feasibility of Mg-based biodegradable microelectrodes for neural recording. Conductive poly(3,4‑ethylenedioxythiophene) (PEDOT) coating was first electrochemically deposited onto Mg microwire surface, and insulating biodegradable poly(glycerol sebacate) (PGS) was then spray-coated onto PEDOT surface to improve the overall properties of microelectrode. The assembled PGS/PEDOT-coated Mg microelectrodes showed high homogeneity in coating thickness, surface morphology and composition before and after in vivo recording. The charge storage capacity (CSC) of PGS/PEDOT-coated Mg microwire (1.72 mC/cm²) was nearly 5 times higher than the standard platinum (Pt) microwire widely used in implantable electrodes. The Mg-based microelectrode demonstrated excellent neural-recording capability and stability during in vivo multi-unit neural recordings in the auditory cortex of a mouse. Specifically, the Mg-based electrode showed clear and stable onset response, and excellent signal-to-noise ratio during spontaneous-activity recordings and three repeats of stimulus-evoked recordings at two different anatomical locations in the auditory cortex. During 10 days of immersion in artificial cerebrospinal fluid (aCSF) in vitro, PGS/PEDOT-coated Mg microelectrodes showed slower degradation and less change in impedance than PEDOT-coated Mg electrodes. The biodegradable PGS coating protected the PEDOT coating from delamination, and prolonged the mechanical integrity and electrical properties of Mg-based microelectrode. Mg-based novel microelectrodes should be further studied toward clinical translation because they can potentially eliminate the risks and costs associated with secondary surgeries for removal of failed or no longer needed electrodes.

[Construction and optimization of Escherichia coli for producing rhamnolipid biosurfactant]

Rhamnolipid biosurfactant is mainly produced by Pseudomonas aeruginosa that is the opportunistic pathogenic strain and not suitable for future industrial development. In order to develop a relatively safe microbial strain for the production of rhamnolipid biosurfactant, we constructed engineered Escherichia coli strains for rhamnolipid production by expressing different copy numbers of rhamnosyltransferase (rhlAB) gene with the constitutive synthetic promoters of different strengths in E. coli ATCC 8739. We further studied the combinatorial regulation of rhlAB gene and rhaBDAC gene cluster for dTDP-1-rhamnose biosynthesis with different synthetic promoters, and obtained the best engineered strain-E. coli TIB-RAB226. Through the optimization of culture temperature, the titer of rhamnolipd reached 124.3 mg/L, 1.17 fold higher than that under the original condition. Fed-batch fermentation further improved the production of rhamnolipid and the titer reached the highest 209.2 mg/L within 12 h. High performance liquid chromatography-mass spectrometry (LC-MS) analysis showed that there are total 5 mono-rhamnolipid congeners with different nuclear mass ratio and relative abundance. This study laid foundation for heterologous biosynthesis of rhanomilipd.

Monitoring codling moth (Lepidoptera: Tortricidae) in sex pheromone-treated orchards with (E)-4,8-dimethyl-1,3,7-nonatriene or pear ester in combination with codlemone and acetic acid

Traps baited with ethyl (E,Z)-2,4-decadienoate (pear ester) or (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) in two- or three-way combinations with the sex pheromone (E,E)-8,10-dodecadien-1-ol (codlemone) and acetic acid (AA) were evaluated for codling moth, Cydia pomonella (L.). All studies were conducted in apple orchards, Malus domestica Borkhausen, treated with sex pheromone dispensers during 2010. Septa were loaded with codlemone, DMNT, and pear ester individually or codlemone with either DMNT or pear ester together (combo lures). Polyethylene vials loaded with AA were added as a co-lure. Residual analyses of field-aged combo lures and weight loss of the AA co-lure were conducted. AA vials lost 50-150 mg wk(-1). Weekly weight loss was not affected by field aging, but was closely correlated with the daily mean temperature. Pear ester was released from septa at a slightly higher but nonsignificant rate than codlemone. DMNT was released at a significantly higher rate than codlemone, and lures were effective for 4 wk. The addition of codlemone to traps baited with either host plant volatile plus AA had either no effect or significantly increased total moth catches. The addition of AA significantly increased the catch of female moths with either combo lure. Total moth catches in traps baited with pear ester or DMNT combo lures and AA did not differ and were either significantly higher or similar to the pear ester combo lure. These data suggest that codling moth may be more effectively monitored in sex pheromone-treated orchards with multi-component lures, including codlemone, AA, and host plant volatiles.

Evaluating dispensers loaded with codlemone and pear ester for disruption of codling moth (Lepidoptera: Tortricidae)

Polyvinyl chloride polymer (PVC) dispensers loaded with ethyl (E,Z)-2,4-decadienoate (pear ester) plus the sex pheromone, (E,E)-8,10-dodecadien-1-ol (codlemone) of codling moth, Cydia pomonella (L.), were compared with PVC dispensers and a commercial dispenser (Isomate-C Plus) loaded with codlemone. Evaluations were conducted in replicated plots (0.1-0.2 ha) in apple, Malus domestica (Borkhausen) during both generations of codling moth from 2007 to 2009. Dispensers were applied at 1,000 ha(-1). Male captures in traps baited with virgin female moths and codlemone lures were recorded. Residual analysis of field-aged dispensers over both moth generations was conducted. Dispensers exhibited linear declines in release rates of both attractants, and pear ester was released at a significantly higher rate than codlemone during both time periods. The proportion of virgin female-baited traps catching males was significantly lower with combo dispenser TRE24 (45/110, mg codlemone/mg pear ester) during the second generation in 2007 and the combo dispensers TRE144 (45/75) and TRE145 (75/45) during the first generation in 2008 compared with Isomate-C Plus. Similarly, male catches in female-baited traps in plots treated with the combo dispensers TRE144 during the first generation in 2008 and TRE23 (75/110) during the second generation, in 2007 were significantly lower than in plots treated with Isomate-C Plus. No significant differences were found for male catches in codlemone-baited traps in plots treated with Isomate-C Plus and any of the combo dispensers. However, male catches were significantly lower in plots treated with Cidetrak CM (codlemone-only dispenser) than the combo TRE144 dispenser during both generations in 2009.

Microencapsulated pear ester enhances insecticide efficacy in walnuts for codling moth (Lepidoptera: Tortricidae) and navel orangeworm (Lepidoptera: Pyralidae)

The efficacy of combining insecticides with a microencapsulated formulation of ethyl (2E,4Z) -2,4-decadienoate (pear ester, PE-MEC) was evaluated in walnuts, Juglans regia L., for codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), and navel orangeworm, Amyelois transitella Walker (Lepidoptera, Pyralidae). Two types of studies were conducted to compare the use of insecticides with and without PE-MEC. In the first study, PE-MEC in combination with reduced rates of insecticides, including chlorpyrifos, phosmet, methoxyfenozide, and codling moth granulovirus were evaluated in single tree replicates. PE-MEC was tested at one to three rates (0.6, 1.8, and 4.4 g active ingredient ha(-1)) with each insecticide. In the second study, seasonal programs including sprays of esfenvalerate, chlorpyrifos, and ethyl parathion at full rates were evaluated in replicated two ha blocks. Significant reductions in nut injury occurred in the single-tree trial with treatments of PE-MEC plus insecticide compared with the insecticides used alone against both pest species; except with methoxyfenozide for navel orangeworm. Similarly, nut injury in the large plots was significantly reduced with the addition of PE-MEC, except for navel orangeworm in one of the two studies. These results suggest that adding pear ester as a microencapsulated spray can improve the efficacy of a range of insecticides for two key pests and foster the development of integrated pest management tactics with reduced insecticide use in walnut.

Finite element analysis of an accordion-like honeycomb scaffold for cardiac tissue engineering

Optimizing the function of tissue engineered cardiac muscle is becoming more feasible with the development of microfabricated scaffolds amenable to mathematical modeling. In the current study, the elastic behavior of a recently developed poly(glycerol sebacate) (PGS) accordion-like honeycomb (ALH) scaffold [Engelmayr et al., 2008. Nature Materials 7 (12), 1003-1010] was analyzed. Specifically, 2D finite element (FE) models of the ALH unit cell (periodic boundary conditions) and tessellations (kinematic uniform boundary conditions) were utilized to determine a representative volume element (RVE) and to retrospectively predict the elastic effective stiffnesses. An RVE of 90 ALH unit cells (≃3.18×4.03mm) was found, indicating that previous experimental uni-axial test samples were mechanically representative. For ALH scaffolds microfabricated from PGS cured 7.5h at 160°C, FE predicted effective stiffnesses in the two orthogonal material directions (0.081±0.012 and 0.033±0.005MPa) matched published experimental data (0.083±0.004 and 0.031±0.002MPa) within 2.4% and 6.4%. Of potential use as a design criterion, model predicted global strain amplifications were lower in ALH (0.54 and 0.34) versus rectangular honeycomb (1.19 and 0.74) scaffolds, appearing to be inversely correlated with previously measured strains-to-failure. Important in matching the anisotropic mechanical properties of native cardiac muscle, FE predicted ALH scaffolds with 50μm wide PGS struts to be maximally anisotropic. The FE model will thus be useful in designing future variants of the ALH pore geometry that simultaneously provide proper cardiac anisotropy and reduced stiffness to enhance heart cell-mediated contractility.

In vitro and in vivo evaluation of a novel oral insulin formulation

AIM

To develop a stable self-emulsifying formulation for oral delivery of insulin.

METHODS

Caco-2 cell line and diabetic beagles were used as in vitro and in vivo models to study the absorption mechanism and the hypoglycemic efficacy of the formulation. In addition, various physicochemical parameters of the formulation such as droplet size, insulin encapsulation efficiency and stability were evaluated.

RESULTS

This formulation enabled changes in barrier properties of Caco-2 monolayers, as referred by transepithelial electrical resistance (TEER) and apparent permeability coefficients (P(app)) of the paracellular marker ranitidine (20-fold greater than control) but not transcellular marker propranolol, suggesting that the opening of tight junctions was involved. In diabetic beagle dogs, the bioavailability of this formulation was up to 15.2% at a dose of 2.5 IU/kg in comparison with the hypoglycemic effect of native insulin (0.5 IU/kg) delivered by subcutaneous injection.

CONCLUSION

This formulation, recently approved by the China State Food and Drug Administration to enter clinical trials, was stable, degradation-protected and absorption-enhanced, and provided a promising formulation for oral insulin delivery.

Hemocompatibility evaluation of poly(glycerol-sebacate) in vitro for vascular tissue engineering

Poly(glycerol-sebacate) (PGS) is an elastomeric biodegradable polyester that could potentially be used to engineer blood vessels in vivo. However, its blood-material interactions are unknown. The objectives of this study were to: (a) fabricate PGS-based biphasic tubular scaffolds and (b) assess the blood compatibility of PGS in vitro in order to get some insight into its potential use in vivo. PGS was incorporated into biphasic scaffolds by dip-coating glass rods with PGS pre-polymer. The thrombogenicity (platelet adhesion and aggregation) and inflammatory potential (IL-1beta and TNFalpha expression) of PGS were evaluated using fresh human blood and a human monocyte cell line (THP-1). The activation of the clotting system was assessed via measurement of tissue factor expression on THP-1 cells, plasma recalcification times, and whole blood clotting times. Glass, tissue culture plastic (TCP), poly(l-lactide-co-glycolide) (PLGA), and expanded polytetrafluorethylene (ePTFE) were used as reference materials. Biphasic scaffolds with PGS as the blood-contacting surface were successfully fabricated. Relative to glass (100%), platelet attachment on ePTFE, PLGA and PGS was 61%, 100%, and 28%, respectively. PGS elicited a significantly lower release of IL-1beta and TNFalpha from THP-1 cells than ePTFE and PLGA. Similarly, relative to all reference materials, tissue factor expression by THP-1 cells was decreased when exposed to PGS. Plasma recalcification and whole blood clotting profiles of PGS were comparable to or better than those of the reference polymers tested.

The beta-oxidation systems of Escherichia coli and Salmonella enterica are not functionally equivalent

Based on its genome sequence, the pathway of beta-oxidative fatty acid degradation in Salmonella enterica serovar Typhimurium LT2 has been thought to be identical to the well-characterized Escherichia coli K-12 system. We report that wild-type strains of S. enterica grow on decanoic acid, whereas wild-type E. coli strains cannot. Mutant strains (carrying fadR) of both organisms in which the genes of fatty acid degradation (fad) are expressed constitutively are readily isolated. The S. enterica fadR strains grow more rapidly than the wild-type strains on decanoic acid and also grow well on octanoic and hexanoic acids (which do not support growth of wild-type strains). By contrast, E. coli fadR strains grow well on decanoic acid but grow only exceedingly slowly on octanoic acid and fail to grow at all on hexanoic acid. The two wild-type organisms also differed in the ability to grow on oleic acid when FadR was overexpressed. Under these superrepression conditions, E. coli failed to grow, whereas S. enterica grew well. Exchange of the wild-type fadR genes between the two organisms showed this to be a property of S. enterica rather than of the FadR proteins per se. This difference in growth was attributed to S. enterica having higher cytosolic levels of the inducing ligands, long-chain acyl coenzyme As (acyl-CoAs). The most striking results were the differences in the compositions of CoA metabolites of strains grown with octanoic acid or oleic acid. S. enterica cleanly converted all of the acid to acetyl-CoA, whereas E. coli accumulated high levels of intermediate-chain-length products. Exchange of homologous genes between the two organisms showed that the S. enterica FadE and FadBA enzymes were responsible for the greater efficiency of beta-oxidation relative to that of E. coli.

Microscopic analysis of ester hydrolysis reaction catalyzed by Candida rugosa lipase

The relationship between the kinetics of the lipase-catalyzed oil hydrolysis and the surface area distribution of oil droplets was investigated using ethyl decanoate and gum Arabic (GA) as a model oil and an emulsifier, respectively. Along an ethyl decanoate concentration gradient between 2 and 8 mM, the initial hydrolysis rate increased at 0.25% (w/v) GA but did not change at 1.0% (w/v) GA. At 0.25% GA, the surface area of droplets was narrowly distributed regardless of the ethyl decanoate concentration. However, at 1.0% GA and with ethyl decanoate concentrations higher than 2 mM, the fraction of relatively large droplets with a surface area larger than approximately 200 microm2, suddenly increased. The microscopy of ethyl decanoate emulsion during the hydrolysis reaction indicates that the large oil droplets were not hydrolyzed. At 20 mM ethyl decanoate where the hydrolysis rate remained the same between 0.25% and 1.0% GA, the surface area of droplets was narrowly distributed at 0.25% and 1.0% GA. Therefore, the constant hydrolysis rate observed in the emulsion of ethyl decanoate between 2 and 8 mM containing GA at 1.0%, is believed to be caused by the relatively large oil droplets with the interface quality differing from that of the small oil droplets.

Cloning and functional characterization of the Pseudomonas aeruginosa rhlC gene that encodes rhamnosyltransferase 2, an enzyme responsible for di-rhamnolipid biosynthesis

Pseudomonas aeruginosa is an opportunistic pathogen capable of producing a wide variety of virulence factors, including extracellular rhamnolipids and lipopolysaccharide. Rhamnolipids are tenso-active glycolipids containing one (mono-rhamnolipid) or two (di-rhamnolipid) L-rhamnose molecules. Rhamnosyltransferase 1 (RhlAB) catalyses the synthesis of mono-rhamnolipid from dTDP-L-rhamnose and beta-hydroxydecanoyl-beta-hydroxydecanoate, whereas di-rhamnolipid is produced from mono-rhamnolipid and dTDP-L-rhamnose. We report here the molecular characterization of rhlC, a gene encoding the rhamnosyltransferase involved in di-rhamnolipid (L-rhamnose-L-rhamnose-beta-hydroxydecanoyl-beta-hydroxydecanoate) production in P. aeruginosa. RhlC is a protein consisting of 325 amino acids with a molecular mass of 35.9 kDa. It contains consensus motifs that are found in other glycosyltransferases involved in the transfer of L-rhamnose to nascent polymer chains. To verify the biological function of RhlC, a chromosomal mutant, RTII-2, was generated by insertional mutagenesis and allelic replacement. This mutant was unable to produce di-rhamnolipid, whereas mono-rhamnolipid was unaffected. In contrast, a null rhlA mutant (PAO1-rhlA) was incapable of producing both mono- and di-rhamnolipid. Complementation of mutant RTII-2 with plasmid pRTII-26 containing rhlC restored the level of di-rhamnolipid production in the recombinant to a level similar to that of the wild-type strain PAO1. The rhlC gene was located in an operon with an upstream gene (PA1131) of unknown function. A sigma54-type promoter for the PA1131-rhlC operon was identified, and a single transcriptional start site was mapped. Expression of the PA1131-rhlC operon was dependent on the P. aeruginosa rhl quorum-sensing system, and a well-conserved lux box was identified in the promoter region. The genetic regulation of rhlC by RpoN and RhlR was in agreement with the observed increasing RhlC rhamnosyltransferase activity during the stationary phase of growth. This is the first report of a rhamnosyltransferase gene responsible for the biosynthesis of di-rhamnolipid.

Development of oral heparin therapy for prophylaxis and treatment of deep venous thrombosis

OBJECTIVE

To review the current research and published literature regarding the development of oral heparin therapy for the prophylaxis and treatment of deep venous thrombosis.

BACKGROUND

Currently, the accepted practice of prophylaxis and/or treatment of acute deep venous thrombosis (DVT) is intravenous or subcutaneous (SQ) heparin followed by oral warfarin or SC low molecular weight heparin (LMWH) therapy followed by warfarin. Both of which are less than ideal. More recently, advances have been made towards an effective oral heparin preparation that would resolve many of the drawbacks to the current therapies.

METHODS

A review of the current and relevant English literature identified via a search of the Medline database from January 1990 to present.

RESULTS

Initial oral heparin therapy for DVT was unsuccessful due to presumed inadequate intestinal absorption as a result of heparin's molecular and structural characteristics. The development of oral heparin therapy, based on combining heparin with the carrier molecule Sodium N-(8[2-hydroxybenzoyl]amino) caprylate (SNAC) to enhance its intestinal absorption and bioavailability for the prophylaxis and treatment of DVT has been demonstrated to be effective in animal models. More recent efforts have been aimed at human trials.

CONCLUSION

Recent advances in prophylaxis and treatment of DVT have stimulated great interest among researchers to develop an effective, convenient, and well tolerated oral therapy. An effective oral heparin therapy may represent an ideal method of prophylaxis and treatment of DVT.

[Studies on chemical constituents in root of Rumex patientia L]

OBJECTIVE

Investigating the chemical constituents in the root of Rumex patientia.

METHOD

Compounds were separated by rechromatography on silica gel. Their structures were determined by spectral analysis and chemical evidence.

RESULT

Eight compounds were isolated and identified as 5-methoxy-7-hydroxy-1 (3H)-benzofuranone (I), 5, 7-dihydroxy-1 (3H)-benzofuranone(II), nonadecanoic acid-2,3-dihydroxypropyl ester(III), torachrysone-8-O-beta-D-glucopyranoside(IV), gallic acid(V), beta-sitosterol(VI), beta-sitosterol-3-O-beta-D-glucopyranoside(VII) and catechin(VIII).

CONCLUSION

Compound III is a new natural products, and compounds I and II were obtained from this plant for the first time.

Role of rhamnolipid biosurfactants in the uptake and mineralization of hexadecane in Pseudomonas aeruginosa

A study was undertaken to investigate the mechanisms for biosurfactant-enhanced hexadecane uptake into Pseudomonas aeruginosa. Two strains of Ps. aeruginosa were studied, one producing rhamnolipids (PG201) and the other rhamnolipid deficient (UO299). Rhamnolipids produced by PG201 acted to increase the solubility of n-hexadecane in the culture medium (from 1.84 to 22.76 microg l(-1). Rates of(l4)C-n-hexadecane uptake and mineralization were higher in PG201 than in UO299. However, the degree of difference was lower than expected. Additional studies were carried out on the cell surface properties of the two strains. During growth on n-hexadecane, the cell surface hydrophobicity of both PG201 (50.5%) and UO299 (33.7%) increased compared with that observed in water-soluble growth substrates (7-8%). Studies were also carried out to ascertain any energy requirements for the transport of n-hexadecane into Ps. aeruginosa cells. The addition of CCCP (an inhibitor of cytochrome oxidase which thereby blocks oxidative phosphorylation) at a range of concentrations caused a marked decrease in n-hexadecane uptake, indicating that n-hexadecane uptake in Ps. aeruginosa is an energy-dependent process. These studies support the hypothesis of alkane transport into microbial cells by direct contact with larger alkane droplets and by pseudosolubilization. Also, it appears that both mechanisms occur simultaneously.

Non-hazardous organic solvents in the paraffin-embedding technique: a rational approach. Aliphatic monoesters for clearing and dewaxing: butyldecanoate

The aim of this study was to substitute hazardous compounds, used in tissue processing and dewaxing, with compounds having lowest possible toxicity and inflammability without impairing the morphology, staining characteristics, or diagnostic value of the tissue sections. All aromatic compounds and aliphatic hydrocarbons (e.g. alkanes, isoparaffins, petroleum distillates, etc.) were rejected, primarily due to their high vapour pressure. Based on a theoretical study of compounds used for clearing, a number of non-hazardous potential substitutes were chosen. The following experimental study narrowed the group to three unbranched, saturated, aliphatic monoesters containing 12-14 carbon atoms. On large-scale testing of these compounds, we found butyldecanoate to be the closest to an ideal substitute for aromatic and aliphatic hydrocarbons in the histology department: the section quality is at least equal to that obtained with xylene. For dewaxing, it is used at 30-35 degrees C. Butyldecanoate is not suitable as a pre-mounting agent. In practice, this is no problem as modern mounting agents permit mounting of coverslips directly from ethanol without impairing the appearance of the section in the microscope. Butyldecanoate has only a slight odour, insignificant vapour pressure (< 0.01 kPa at 20 degrees C), and does not present a fire hazard (flash point 134 degrees C). The introduction of this compound in the laboratory poses no health hazard, and the substance is biodegradable.

Low neuroleptic serum levels in patients receiving fluphenazine decanoate

The authors monitored serum levels of fluphenazine in nine patients following injections of fluphenazine decanoate ranging from 10 to 75 mg. Levels were detected by a radioreceptor assay based on the ability of the drug to complete with 3H-spiroperidol for binding to dopamine receptors in rat caudate membranes. Serum levels of fluphenazine were quite stable over a 2- to 3-week period following single intramuscular injections of the decanoate and correlated with injected dose. Following decanoate treatment serum levels of fluphenazine are substantially lower than levels observed for most other neuroleptics administered orally. This raises questions as to how fluphenazine decanoate can exert therapeutic actions.

Effects of structural changes on the tumor-promoting activity of phorbol myristate acetate on mouse skin

4a alpha-Phorbol-9,9a-didecanoate, 4a alpha-phorbol-9-myristate-9a-acetate, and phorbol-9-myristate-9a-acetate-3-aldehyde were tested for skin tumor-promoting activity by using 7,12-dimethylbenz(a)anthracene as the initiating agent. There were 30 female ICR/Ha mice/group, and tests were continued for 434 to 461 days. 4a alpha-Phorbol-9,9a-didecanoate and 4a alpha-phorbol-9-myristate-9a-acetate were devoid of tumor-promoting activity. Phorbol-9-myristate-9a-acetate-3-aldehyde resulted in 10 mice with papillomas, 2 of which also bore squamous carcinomas of the skin. The positive control group, in which phorbol myristate acetate was used as promoting agent, resulted in 30 mice bearing multiple papillomas and 15 bearing squamous carcinomas of the skin. The effects of structural and stereochemical changes on tumor-promoting activity suggest that a primary interaction of the phorbol ester series is binding at specific sites on the plasma membrane.

Weight changes with depot neuroleptic maintenance therapy

A prospective study of schizophrenic patients prescribed injectable depot neuroleptic drugs as maintenance therapy showed a clinically significant weight gain in 55% of patients. No significant difference was shown between flupenthixol decanoate and fluphenazine decanoate, nor was a clinically meaningful relationship shown with dose, or the use of anti-parkinsonian drugs. The weight gain continued for at least 2 years following a mental state relapse. It is suggested that the monitoring of weight and giving of appropriate advice on diet are two essential in maintenance therapy of chronic schizophrenia.

Drug monitoring at an Australia depot phenothiazine clinic

Three aspects of treatment with injectable neuroleptics, are presented. An individualized approach to the dosage of Fluphenazine decanoate must be practiced in conjunction with, and taking into account the time spent in treatment and the sex and age variables reported. Our flexible approach to the interval between injections, indicated a large group could be maintained at intervals of 5 to 8 weeks. Complex and challenging problems can be found with antiparkinsonian drugs; 30% of nearly 400 outpatients still require these drugs.