Directed Enzyme Evolution and Encapsulation in Peptide Nanospheres of Quorum Quenching Lactonase as an Antibacterial Treatment against Plant Pathogen

The need to increase agricultural yield has led to an extensive use of antibiotics against plant pathogens, which has resulted in the emergence of resistant strains. Therefore, there is an increasing demand for new methods, preferably with lower chances of developing resistant strains and a lower risk to the environment or public health. Many Gram-negative bacterial pathogens use quorum sensing, a population-density-dependent regulatory mechanism, to monitor the secretion of N-acyl-homoserine lactones (AHLs) and pathogenicity. Therefore, quorum sensing represents an attractive antivirulence target. AHL lactonases hydrolyze AHLs and have potential antibacterial properties; however, their use is limited by thermal instability and durability, or low activity. Here, we demonstrate that an AHL lactonase from the phosphotriesterase-like lactonase family exhibits high activity with the AHL secreted from the plant pathogen Erwinia amylovora and attenuates infection in planta. Using directed enzyme evolution, we were able to increase the enzyme's temperature resistance (T₅₀, the temperature at which 50% of the activity is retained) by 8 °C. Then, by performing enzyme encapsulation in nanospherical capsules composed of tertbutoxycarbonyl-Phe-Phe-OH peptide, the shelf life was extended for more than 5 weeks. Furthermore, the encapsulated and free mutant were able to significantly inhibit up to 70% blossom's infection in the field, achieving the same efficacy as seen with antibiotics commonly used today to treat the plant pathogen. We conclude that specific AHL lactonase can inhibit E. amylovora infection in the field, as it degrades the AHL secreted by this plant pathogen. The combination of directed enzyme evolution and peptide nanostructure encapsulation significantly improved the thermal resistance and shelf life of the enzyme, respectively, increasing its potential in future development as antibacterial treatment.

Three-Dimensional Protein Cage Array Capable of Active Enzyme Capture and Artificial Chaperone Activity

Development of protein cages for encapsulation of active enzyme cargoes and their subsequent arrangement into a controllable three-dimensional array is highly desirable. However, cargo capture is typically challenging because of difficulties in achieving reversible assembly/disassembly of protein cages in mild conditions. Herein we show that by using an unusual ferritin cage protein that undergoes triggerable assembly under mild conditions, we can achieve reversible filling with protein cargoes including an active enzyme. We demonstrate that these filled cages can be arrayed in three-dimensional crystal lattices and have an additional chaperone-like effect, increasing both thermostability and enzymatic activity of the encapsulated enzyme.

Proteolytic Nanoparticles Replace a Surgical Blade by Controllably Remodeling the Oral Connective Tissue

Surgical blades are common medical tools. However, blades cannot distinguish between healthy and diseased tissue, thereby creating unnecessary damage, lengthening recovery, and increasing pain. We propose that surgical procedures can rely on natural tissue remodeling tools-enzymes, which are the same tools our body uses to repair itself. Through a combination of nanotechnology and a controllably activated proteolytic enzyme, we performed a targeted surgical task in the oral cavity. More specifically, we engineered nanoparticles that contain collagenase in a deactivated form. Once placed at the surgical site, collagenase was released at a therapeutic concentration and activated by calcium, its biological cofactor that is naturally present in the tissue. Enhanced periodontal remodeling was recorded due to enzymatic cleavage of the supracrestal collagen fibers that connect the teeth to the underlying bone. When positioned in their new orientation, natural tissue repair mechanisms supported soft and hard tissue recovery and reduced tooth relapse. Through the combination of nanotechnology and proteolytic enzymes, localized surgical procedures can now be less invasive.

Endogenous Catalytic Generation of O2 Bubbles for In Situ Ultrasound-Guided High Intensity Focused Ultrasound Ablation

High intensity focused ultrasound (HIFU) surgery generally suffers from poor precision and low efficiency in clinical application, especially for cancer therapy. Herein, a multiscale hybrid catalytic nanoreactor (catalase@MONs, abbreviated as C@M) has been developed as a tumor-sensitive contrast and synergistic agent (C&SA) for ultrasound-guided HIFU cancer surgery, by integrating dendritic-structured mesoporous organosilica nanoparticles (MONs) and catalase immobilized in the large open pore channels of MONs. Such a hybrid nanoreactor exhibited sensitive catalytic activity toward H₂O₂, facilitating the continuous O₂ gas generation in a relatively mild manner even if incubated with 10 μM H₂O₂, which finally led to enhanced ablation in the tissue-mimicking PAA gel model after HIFU exposure mainly resulting from intensified cavitation effect. The C@M nanoparticles could be accumulated within the H₂O₂-enriched tumor region through enhanced permeability and retention effect, enabling durable contrast enhancement of ultrasound imaging, and highly efficient tumor ablation under relatively low power of HIFU exposure in vivo. Very different from the traditional perfluorocarbon-based C&SA, such an on-demand catalytic nanoreactor could realize the accurate positioning of tumor without HIFU prestimulation and efficient HIFU ablation with a much safer power output, which is highly desired in clinical HIFU application.

Biomimetic Strategy To Reversibly Trigger Functionality of Catalytic Nanocompartments by the Insertion of pH-Responsive Biovalves

We describe an innovative strategy to generate catalytic compartments with triggered functionality at the nanoscale level by combining pH-reversible biovalves and enzyme-loaded synthetic compartments. The biovalve has been engineered by the attachment of stimuli-responsive peptides to a genetically modified channel porin, enabling a reversible change of the molecular flow through the pores of the porin in response to a pH change in the local environment. The biovalve functionality triggers the reaction inside the cavity of the enzyme-loaded compartments by switching the in situ activity of the enzymes on/off based on a reversible change of the permeability of the membrane, which blocks or allows the passage of substrates and products. The complex functionality of our catalytic compartments is based on the preservation of the integrity of the compartments to protect encapsulated enzymes. An increase of the in situ activity compared to that of the free enzyme and a reversible on/off switch of the activity upon the presence of a specific stimulus is achieved. This strategy provides straightforward solutions for the development of catalytic nanocompartments efficiently producing desired molecules in a controlled, stimuli-responsive manner with high potential in areas, such as medicine, analytical chemistry, and catalysis.

Poly(2-vinyl-4,4-dimethylazlactone)-functionalized magnetic nanoparticles as carriers for enzyme immobilization and its application

Fabrication of various efficient enzyme reactors has triggered increasing interests for its extensive applications in biological and clinical research. In this study, magnetic nanoparticles were functionalized by a biocompatible reactive polymer, poly(2-vinyl-4,4-dimethylazlactone), which was synthesized by reversible addition-fragmentation chain transfer polymerization. Then, the prepared polymer-modified magnetic nanoparticles were employed as favorable carriers for enzyme immobilization. l-Asparaginase was selected as the model enzyme to fabricate the enzyme reactor, and the prepared enzyme reactor exhibited high loading capacity of 318.0 μg mg(-1) magnetic nanoparticle. Interestingly, it has been observed that the enzymolysis efficiency increased slightly with the lengthened polymer chain, resulting from the increased immobilization amount of enzyme. Meanwhile, the immobilized enzyme could retain more than 95.7% activity after 10 repeated uses and maintain more than 72.6% activity after 10 weeks storage. Moreover, an extracorporeal shunt system was simulated to estimate the potential application capability of the prepared l-asparaginase reactor in acute lymphoblastic leukemia treatment.

Effect of immobilized hyaluronidase on stem and progenitor cells in pulmonary fibrosis

The effect of immobilized hyaluronidase on stem and progenitor cells of the lungs was studied on the model of partially reversible toxic bleomycin-induced pulmonary fibrosis in C57Bl/6 mice. During the inflammation phase, immobilized hyaluronidase reduced infiltration of alveolar interstitium with hemopoietic stem cells Sca-1(+), c-Kit(+), CD34(-), (CD3, CD45R (B220), Ly6C, Ly6G (Gr1), CD11b (Mac1), TER-119)(-). Improvement of histological parameters of bleomycin lungs during the phase of collagen fiber deposition after the treatment was accompanied by accumulation of mesenchymal multipotent stromal cells (CD31(-), CD34(-), CD45(-), CD44(+), CD73(+), CD90(+), CD106(+)decrease in the population of pan-hemopoietic cells (CD45(+)), accelerated restoration of the content of endothelial cells, and inhibition of clonal activity of fibroblast precursors (CD45(-)).

Efficacy and tolerability of pegloticase for the treatment of chronic gout in patients refractory to conventional treatment: two randomized controlled trials

CONTEXT

Patients with chronic disabling gout refractory to conventional urate-lowering therapy need timely treatment to control disease manifestations related to tissue urate crystal deposition. Pegloticase, monomethoxypoly(ethylene glycol)-conjugated mammalian recombinant uricase, was developed to fulfill this need.

OBJECTIVE

To assess the efficacy and tolerability of pegloticase in managing refractory chronic gout.

DESIGN, SETTING, AND PATIENTS

Two replicate, randomized, double-blind, placebo-controlled trials (C0405 and C0406) were conducted between June 2006 and October 2007 at 56 rheumatology practices in the United States, Canada, and Mexico in patients with severe gout, allopurinol intolerance or refractoriness, and serum uric acid concentration of 8.0 mg/dL or greater. A total of 225 patients participated: 109 in trial C0405 and 116 in trial C0406.

INTERVENTION

Twelve biweekly intravenous infusions containing either pegloticase 8 mg at each infusion (biweekly treatment group), pegloticase alternating with placebo at successive infusions (monthly treatment group), or placebo (placebo group).

MAIN OUTCOME MEASURE

Primary end point was plasma uric acid levels of less than 6.0 mg/dL in months 3 and 6.

RESULTS

In trial C0405 the primary end point was reached in 20 of 43 patients in the biweekly group (47%; 95% CI, 31%-62%), 8 of 41 patients in the monthly group (20%; 95% CI, 9%-35%), and in 0 patients treated with placebo (0/20; 95% CI, 0%-17%; P < .001 and <.04 for comparisons between biweekly and monthly groups vs placebo, respectively). Among patients treated with pegloticase in trial C0406, 16 of 42 in the biweekly group (38%; 95% CI, 24%-54%) and 21 of 43 in the monthly group (49%; 95% CI, 33%-65%) achieved the primary end point; no placebo-treated patients reached the primary end point (0/23; 95% CI, 0%-15%; P = .001 and < .001, respectively). When data in the 2 trials were pooled, the primary end point was achieved in 36 of 85 patients in the biweekly group (42%; 95% CI, 32%-54%), 29 of 84 patients in the monthly group (35%; 95% CI, 24%-46%), and 0 of 43 patients in the placebo group (0%; 95% CI, 0%-8%; P < .001 for each comparison). Seven deaths (4 in patients receiving pegloticase and 3 in the placebo group) occurred between randomization and closure of the study database (February 15, 2008).

CONCLUSION

Among patients with chronic gout, elevated serum uric acid level, and allopurinol intolerance or refractoriness, the use of pegloticase 8 mg either every 2 weeks or every 4 weeks for 6 months resulted in lower uric acid levels compared with placebo.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00325195.

RNA-directed packaging of enzymes within virus-like particles

Packaged molecular machines are available in large amounts using dual expression vectors that guide the preparation of Qβ virus-like particles encapsulating multiple copies of functional enzymes. Packaging is promoted by RNA aptamer sequences that bridge between the coat protein and a peptide tag fused to the desired cargo. Peptidase E and luciferase were thus encapsulated and shown to be catalytically active inside the particle. The encapsulated enzymes are less sensitive to inactivation by heating and surface adsorption than the corresponding free enzymes. This system represents a modular way to marry catalytic activity with robust scaffolding for the development of multifunctional materials.

A 9-yr evaluation of carrier erythrocyte encapsulated adenosine deaminase (ADA) therapy in a patient with adult-type ADA deficiency

Adenosine deaminase (ADA) deficiency is an inherited disorder which leads to elevated cellular levels of deoxyadenosine triphosphate (dATP) and systemic accumulation of its precursor, 2-deoxyadenosine. These metabolites impair lymphocyte function, and inactivate S-adenosylhomocysteine hydrolase (SAHH) respectively, leading to severe immunodeficiency. Enzyme replacement therapy with polyethylene glycol-conjugated ADA is available, but its efficacy is reduced by anti-ADA neutralising antibody formation. We report here carrier erythrocyte encapsulated native ADA therapy in an adult-type ADA deficient patient. Encapsulated enzyme is protected from antigenic responses and therapeutic activities are sustained. ADA-loaded autologous carrier erythrocytes were prepared using a hypo-osmotic dialysis procedure. Over a 9-yr period 225 treatment cycles were administered at 2-3 weekly intervals. Therapeutic efficacy was determined by monitoring immunological and metabolic parameters. After 9 yr of therapy, erythrocyte dATP concentration ranged between 24 and 44 micromol/L (diagnosis, 234) and SAHH activity between 1.69 and 2.29 nmol/h/mg haemoglobin (diagnosis, 0.34). Erythrocyte ADA activities were above the reference range of 40-100 nmol/h/mg haemoglobin (0 at diagnosis). Initial increases in absolute lymphocyte counts were not sustained; however, despite subnormal circulating CD20(+) cell numbers, serum immunoglobulin levels were normal. The patient tolerated the treatment well. The frequency of respiratory problems was reduced and the decline in the forced expiratory volume in 1 s and vital capacity reduced compared with the 4 yr preceding carrier erythrocyte therapy. Carrier erythrocyte-ADA therapy in an adult patient with ADA deficiency was shown to be metabolically and clinically effective.

Immobilization and bioactivity of glucose oxidase in hydrogel microspheres formulated by an emulsification–internal gelation–adsorption–polyelectrolyte coating method

The purpose of this study was to develop a novel microsphere formulation of glucose oxidase (GOX) with high drug loading, encapsulation efficiency and bioactivity. GOX was encapsulated in alginate/chitosan microspheres (ACMS) using an emulsification-internal gelation, followed by GOX adsorption and polyelectrolyte coating method. The factors influencing GOX loading, encapsulation efficiency and activity of the loaded GOX were investigated. The resultant ACMS in wet state were spherical with a mean diameter of about 138 microm. GOX loading was found to be pH dependent. High GOX loading and encapsulation efficiency were achieved when the pH of the adsorption medium was lower than the isoelectric point (pI) of GOX. GOX loading and encapsulation efficiency increased with increasing GOX concentration in the loading solution, but decreased with increasing chitosan concentration in the coating solution. The activity of loaded GOX increased and then decreased with increasing chitosan concentration. The activity of GOX in ACMS was maintained and showed sustained production of H(2)O(2) as compared to free GOX. Around 90% of the original activity of immobilized GOX remained after lyophilization and storage at -20 degrees C for a month. These results suggest that the ACMS and the fabrication method are suitable for microencapsulation of proteins like GOX.

Enzymosomes with surface-exposed superoxide dismutase: In vivo behaviour and therapeutic activity in a model of adjuvant arthritis

Acylated Superoxide Dismutase (Ac-SOD) enzymosomes, liposomal enzymatic systems expressing catalytic activity in the intact form, were previously characterized. The main scope of the present work was to investigate the biological behaviour of Ac-SOD inserted in the lipid bilayer of liposomes, in comparison with SOD located in the aqueous compartment of liposomes. Two types of liposomes were used: conventional liposomes presenting an unmodified external surface and long circulating liposomes coated with poly (ethylene glycol) (PEG). Liposomal formulations of Ac-SOD and SOD were prepared and labelled with indium-111 and their in vivo fate compared. Data obtained led us to the conclusion that, for liposomes coated with PEG the in vivo fate was not influenced by the insertion of Ac-SOD in the lipid bilayers. The potential therapeutic effect of Ac-SOD enzymosomes was compared with SOD liposomes in a rat model of adjuvant arthritis. A faster anti-inflammatory effect was observed for Ac-SOD enzymosomes by monitoring the volume of the inflamed paws. The present results allowed us to conclude that Ac-SOD enzymosomes are nano-carriers combining the advantages of expressing enzymatic activity in intact form and thus being able to exert therapeutic effect even before liposomes disruption, as well as acting as a sustained release of the enzyme.

Immobilisation of cardosin A in chitosan sponges as a novel implant for drug delivery

Cardosin A is extracted from the pistils of the plant Cynara cardunculus L. and chitosan is a polysaccharide derived from chitin with valuable properties as a biomaterial. In this work we report our experiments on the synthesis of chitosan sponges and immobilisation of cardosin A, by entrapment. We observed that 10-15% of the incorporated cardosin A were released over 6 days of incubation. In addition, we could also note that this immobilisation procedure did not induce any specificity alterations on cardosin A. The specificity study of the enzyme, using beta-chain of oxidised insulin, showed that the immobilised and released enzymes have the same hydrolysis pattern as the free enzyme. The ability of this enzyme to hydrolyse type I collagen was maintained, after the immobilisation procedure. The biocompatibility in vivo of these sponges was evaluated by histological staining after implantation in rats submitted to abdominal surgery. Results of this study demonstrated that these chitosan sponges are very promising vehicles for the application of cardosin A, in abdominal cavity for prevention and reduction of the adhesions formation.

polyethylene glycol-conjugated adenosine deaminase (ADA) therapy provides temporary immune reconstitution to a child with delayed-onset ADA deficiency

We describe the effects of polyethylene glycol-conjugated adenosine deaminase (ADA) replacement therapy on lymphocyte counts, activation, apoptosis, proliferation, and cytokine secretion in a 14-month-old girl with "delayed-onset" ADA deficiency and marked immunodysregulation. Pretreatment lymphopenia affected T cells (CD4, 150/microl; CD8, 459/microl), B cells (16/microl), and NK cells (55/microl). T cells were uniformly activated and largely apoptotic (CD4, 59%; CD8, 82%); and T-cell-dependent cytokine levels in plasma were elevated, including the levels of interleukin 2 (IL-2; 26 pg/ml), IL-4 (81 pg/ml), IL-5 (46 pg/ml), gamma interferon (1,430 pg/ml), tumor necrosis factor alpha (210 pg/ml), and IL-10 (168 pg/ml). Mitogen-stimulated peripheral blood mononuclear cells show reduced IL-2 secretion and proliferation. During the first 5 months of therapy there was clinical improvement and partial immune reconstitution, with nearly normal lymphocyte subset numbers, reduced T-cell activation and CD4-cell apoptosis, and decreased plasma cytokine levels. In parallel, IL-2 secretion and the lymphocyte mitogenic response improved. Between 4 and 7 months, immunoglobulin G antibodies to bovine ADA developed and resulted in the complete reversal of immune recovery.

Calcium phosphate-alginate microspheres as enzyme delivery matrices

The present study concerns the preparation and initial characterisation of novel calcium titanium phosphate-alginate (CTP-alginate) and hydroxyapatite-alginate (HAp-alginate) microspheres, which are intended to be used as enzyme delivery matrices and bone regeneration templates. Microspheres were prepared using different concentrations of polymer solution (1% and 3% w/v) and different ceramic-to-polymer solution ratios (0.1, 0.2 and 0.4 w/w). Ceramic powders were characterised using X-ray diffraction, laser granulometry, Brunauer, Emmel and Teller (BET) method for the determination of surface area, zeta potential and Fourier transform infrared spectroscopy (FT-IR). Alginate was characterised using high performance size exclusion chromatography. The methodology followed in this investigation enabled the preparation of homogeneous microspheres with a uniform size. Studies on the immobilisation and release of the therapeutic enzyme glucocerebrosidase, employed in the treatment of Gaucher disease, were also performed. The enzyme was incorporated into the ceramic-alginate matrix before gel formation in two different ways: pre-adsorbed onto the ceramic particles or dispersed in the polymeric matrix. The two strategies resulted in distinct release profiles. Slow release was obtained after adsorption of the enzyme to the ceramic powders, prior to preparation of the microspheres. An initial fast release was achieved when the enzyme and the ceramic particles were dispersed in the alginate solution before producing the microspheres. The latter profile is very similar to that of alginate microspheres. The different patterns of enzyme release increase the range of possible applications of the system investigated in this work.

Enzyme loaded biodegradable microspheres in vitro ex vivo evaluation

Prolidase is a naturally occurring enzyme involved in the final stage of protein catabolism. Deficient enzyme activity causes prolidase deficiency (PD), a rare autosomal recessive inherited disorder whose main manifestations are chronic, intractable ulcerations of the skin, particularly of lower limbs. Although several attempts have been made towards the treatment of this pathology, a cure for this disease has yet to be found. The purpose of this work is to evaluate the possibility of enzyme replacement therapy through prolidase microencapsulation in biodegradable microspheres. The poly(D,L-lactide-co-glycolide) (PLGA) prolidase loaded microparticulate systems have been prepared utilizing the w-o-w double emulsion solvent evaporation method. They have been characterized "in vitro" by morphological analysis, total protein content and an in vitro dissolution test of active protein. "Ex vivo" evaluation of prolidase activity from the microspheres has been performed on cellular extracts of cultured skin fibroblasts from healthy subjects (controls) and from patients affected by PD. The results reported in this work on prolidase from pig kidney (available on the market) demonstrate the positive role of microencapsulation as a process of enzymatic activity stabilization inside PLGA microspheres achieving both in vitro and ex vivo active enzyme release. This formulation can be proposed as a parenteral depot drug delivery system.

Pegaspargase-induced pancreatitis

BACKGROUND

The purpose of this study is to report the incidence of pancreatitis in patients treated with pegaspargase in our hospital during a 2-year period.

PROCEDURE

We identified episodes of pancreatitis related to the intramuscular administration of pegaspargase 2,500 IU/m(2) for the treatment of childhood hematological malignancies during a 2-year period (May 1996-April 1998). Patients were evaluated clinically and by sequential serum amylase and lipase determinations and radiographic examinations. For comparison, episodes of pancreatitis in patients who only received native Escherichia coli L-asparaginase were examined during the same time period.

RESULTS

Nine children with acute lymphoblastic leukemia (ALL) of 50 (18%) patients who received pegaspargase were diagnosed to have pancreatitis. All had prior therapy with native L-asparaginase. These children developed symptoms consisting of abdominal pain, nausea, vomiting, and decreased appetite within a median of 15 days from the onset of pegaspargase administration. Six patients became symptomatic after their initial dose. Seven patients developed severe or unacceptable toxicity (grades 3 and 4), measured by increased amylase (>2 times normal) and lipase levels or radiographic evidence of pancreatic inflammation or pseudocyst. One patient also developed hyperammonemia and encephalopathy. In contrast, only one out of 52 (1.9%) ALL patients who received native E. coli L-asparaginase during the same time period developed pancreatitis (P= 0.007).

CONCLUSION

Clinicians should be aware of a possible higher incidence of pancreatitis associated with pegaspargase.

Combination therapy with methotrexate, vincristine, polyethylene-glycol conjugated-asparaginase, and prednisone in the treatment of patients with refractory or recurrent acute lymphoblastic leukemia

BACKGROUND

L-asparaginase in combination with methotrexate has synergistic antileukemic activity in a schedule-dependent fashion. A new preparation of L-asparaginase, polyethylene-glycol conjugated (PEG)-asparaginase, is a pharmacologically different formulation of L-asparaginase with distinct properties including a longer half-life and less immunogenic properties.

METHODS

Patients with refractory or recurrent acute lymphoblastic leukemia (ALL) were treated with a combination of methotrexate (MTX), vincristine, PEG-asparaginase, and prednisone (MOAP). The treatment was comprised of MTX, 100 mg/m(2) intravenously (i.v.), over 15 minutes on Days 1 and 14; PEG-asparaginase, 2500 IU/m(2), with a maximum dose of 3750 IU i.v. approximately 4-6 hours after MTX on Days 1 and 14; vincristine, 1.4 mg/m(2) (maximum dose, 2 mg) i.v., over 15 minutes on Days 1, 7, and 14; and prednisone, 200 mg daily orally, on Days 1-5 and 14-19.

RESULTS

Thirty-two patients with a median age of 34 years (range, 20-74 years) were treated. Eight patients (25%) had ALL that was refractory to prior therapy and 24 patients (75%) had recurrent disease. Seven patients (22%) achieved a complete remission (CR). Five patients (16%) died early due to infections. Features associated with a poor response were high pretreatment lactate dehydrogenase levels and Philadelphia chromosome positive disease. The median duration of CR was 16 weeks and the overall median survival after MOAP therapy was 12 weeks. Anaphylactic reactions were not observed during MOAP combination therapy.

CONCLUSIONS

MOAP is an active regimen in patients with refractory or recurrent ALL. This regimen is well tolerated and is not associated with allergic reactions. However, further studies regarding the pharmacologic interaction of MTX with PEG-asparaginase are needed to optimize this regimen.

Organophosphate skin decontamination using immobilized enzymes

We previously demonstrated that a combination of cholinesterase (ChE) pre-treatment with an oxime is an effective measure against soman and sarin. We describe here a novel approach for the preparation of covalently linked ChEs which are immobilized to a polyurethane matrix. Such preparation of ChE-sponges enhances the stability and usefulness of the enzymes in non-physiological environments. The ChE-sponges, which can be molded to any form, can effectively be used to remove and decontaminate organophosphates (OPs) from surfaces, biological (skin or wounds) or otherwise (clothing or sensitive medical equipment), or the environment. The ChE-sponges retained their catalytic activity under conditions of temperature, time, and drying where the native soluble enzyme would rapidly denature, and can be reused in conjunction with oximes many times. The ChE-sponge in the presence of oxime repeatedly detoxified OPs such as DFP or MEPQ. These developments in ChE technology have extended the applicability of OP scavengers from in vivo protection, to a variety of external detoxification and decontamination schemes. In addition to treatment of OP-contaminated soldiers, the ChE-sponge could protect medical personnel from secondary contamination while attending chemical casualties, and civilians exposed to pesticides or highly toxic nerve agents such as sarin.

[The parenteral administration of terridecase in the treatment of suppurative-inflammatory diseases of the hand]

Patients with purulent inflammatory diseases were treated by parenteral administration of terrydecaza (polyglucin-immobilised terrylythin). It was noted that injections of terrydecaza facilitated the penetration of antibiotics to the purulent focus. The terms of cleansing the purulent wounds and transition of the inflammatory process to the second stage were 2-3 days shorter. The microcirculation was improved by the daily thermographic monitoring method. The increased penetration through the biological membranes was confirmed by higher concentration of middle weight molecules in plasma of the venous blood flowing off from the purulent focus.

Multiple emulsions for the delivery of proteins

Multiple emulsions are unique in that a true liquid phase is maintained separate from an external aqueous phase. This may be especially important for bioactive molecules that cannot be appropriately stabilized in the solid state. In addition, the separation of aqueous phases enables highly specialized environments, conducive to protein activity, to be prepared. The physical instability of conventional systems remains a major factor limiting their wider application. Attempts to improve the physical stability of the aqueous dispersions through interfacial complexation and the use of micro-emulsions are improving the short-term stability. As an alternative approach, solid-state emulsions attempt to store the multiple emulsion as a solid. Although solid-state emulsions appear to have the potential to be useful protein delivery systems, a substantial experimental data base has yet to be generated.

[Possibilities of the use of immobilized proteolytic enzyme immozymase in tuberculosis]

The paper summarises the experience gained in the use of immozymase in tuberculous patients to advance the disease diagnosis and treatment. Immozymase proved valuable in obtaining sputum enriched with M. tuberculosis in patients who were previously considered noncarriers. M. tuberculosis became detectable in 28.3% of them. Immozymase instillations of the urethra before its massage for stimulation of prostatic secretion led to getting secretion in all the patients (0.35 ml, on the average). Immuzymase inhalations were used in the treatment of purulent bronchitis in patients with destructive pulmonary tuberculosis in conservative and preoperative regimens. Postoperative immozymase inhalations promoted prevention of pleuropulmonary complications. Open treatment of the caverns with immozymase after cavernotomy shortens the treatment duration. Positive results were also reached in the treatment of pleural empyema.

[The use of trypsin and lysozyme immobilized on a cellulose carrier in treating otitis externa]

The authors present a theoretical and practical validation of lysozyme+trypsin therapy for diffuse external otitis. A total of 32 patients were treated by a powder of trypsin immobilized on cellulose carrier as well as lysozyme and trypsin immobilized on gauze turundae. The treatment proved effective against bacterial and fungal external otitis.

Oral treatment for jaundice using immobilized bilirubin oxidase

Jaundice is characterized by an excessive accumulation of bilirubin in the blood and tissues. A novel approach to reduce plasma levels of bilirubin by blocking its enterohepatic circulation was investigated. The treatment consisted of oral administration of immobilized bilirubin oxidase, which could oxidize bilirubin in the intestine to less toxic and more water-soluble products. In vivo administration of 0.1 to 2.0 mg/day of immobilized enzyme over a four-day period to chronically jaundiced Gunn rats effectively lowered plasma bilirubin levels, but only when the molar ratio of total serum bilirubin to rat serum albumin (B/RSA) was larger than 0.35. Plasma bilirubin concentration decreased in that group from an initial value of 11.3 to 6.3 mg/dl (-40%, n = 5) after eight days. This decrease was statistically significant (p < 0.05 by Student's t test). However, administration of bilirubin oxidase to rats with a B/RSA ratio less than 0.35 (n = 10) resulted in no statistically significant change in plasma bilirubin concentration.

[Treatment of suppurative diseases of soft tissues by CO2 laser and immobilized trypsin]

The results of treatment of 245 patients with purulent diseases of the soft tissues are discussed. The course of the wound process was most favourable with the use of immobilized trypsin on gauze in the management of wounds formed after surgical debridement of purulent foci by means of CO2 laser. The method made it possible to accelerate the processes of necrolysis, provide a stable low level of dissemination of bacteria in the wound tissues, reduce the term of preparation of the wound for the application of secondary sutures and the terms of healing.

[Use of immozymase in the treatment of suppurative wounds]

The authors discuss the results of application of proteinase preparations immobilized on a water soluble carrier (Immozymase) and a water insoluble carrier (Profezyme) in the management of ++pyo-necrotic processes of various etiology and localization in 1,059 patients. The wounds were cleansed 1.5-2 times quicker than with the traditional methods of treatment. Immobilized proteinases possessing a prolonged therapeutic effect were found to stimulate the regeneration process. The authors believe the use of Immozymase to be promising in the treatment of purulent foci which are drained with difficulty and in intracavitary administration for treating purulent processes in the thoracic or abdominal cavity.

[Evaluation of the effect of intravenous administration of streptodecase on the extent of the damage in myocardial infarction]

Precordial mapping was employed to examine 29 patients with acute anterior transmural myocardial infarction (MI). Seventeen of them received intravenous streptokinase, eleven underwent symptomatic therapy. The size of the lesion was assessed in the course of the disease. It is shown that streptokinase administration within the initial 6 hours of MI promotes arrest of the ischemic lesion augmentation and eventually diminishes the area of MI.

[Characteristics of wound process after high-energy laser debridement and enzyme treatment]

The results of ++clinico-bacterial examination of 168 patients provide evidence for the efficacy of CO2-laser treatment of a purulent wound; it reduces contamination of the tissues, 1,000-10,000-fold as a result of which surgical debridement of the purulent wound is completed in most cases by the application of a primary suture. The use of immobilized proteolytic enzymes in the postoperative period facilitates further cleansing of the wound, prevents the development of secondary infection, accelerates the change of the wound process to the phase of regeneration, promotes an uneventful postoperative course and healing of the wound within a lesser period as compared to the control group.

Effects of oral administration of artificial cells immobilized phenylalanine ammonia-lyase on intestinal amino acids of phenylketonuric rats

Intraperitoneal injections of para-Chlorophenylalanine methyl ester and Phenylalanine solution were used to produce phenylketonuria in rats. By the use of different diets and orally administered Phenylalanine ammonia lyase (PAL) loaded artificial cells, the Phenylalanine concentration gradient between the plasma and the gastro-intestinal lumen was varied. Other changes in related amino acids levels were also studied. The transport of neutral amino acids, across the gastro-intestinal membrane to the plasma, was decreased by the presence of a high concentration of phenylalanine in the intestinal lumen. Unlike Phenylalanine free diet, oral administration of PAL loaded artificial cells to PKU rats on normal diets resulted in much lower levels of intestinal phenylalanine.

[Preparation of lysozyme immobilized on textile carriers and its use in treating suppurative wounds]

Immobilized forms of lysozyme were prepared by its covalent binding on dialdehyde cellulose and polycaproamide fibres as woven and knitted fabrics respectively. The preparations were estimated by the content of protein and bacteriolytic activity. The lysozyme activity per 1 g of the carrier and the protein content on dialdehyde cellulose were several times higher than those on polycaproamide while the specific activity of lysozyme on the polycaproamide carrier was somewhat higher than that on dialdehyde cellulose. The effect of the immobilized lysozyme in treatment of purulent wounds was studied on albino rats. It was shown that the periods of the wound healing with the use of the immobilized lysozyme were shorter than those with the use of native lysozyme. Cytological and morphological investigation of the wound wall confirmed the higher efficacy of the lysozyme immobilized forms in treatment of purulent wounds as compared to the use of the native enzyme.

Plasma/intestinal concentration patterns suggestive of entero-portal recirculation of amino acids: effects of oral administration of asparaginase, glutaminase and tyrosinase immobilized by microencapsulation in artificial cells

This study suggests the presence of an entero-portal recirculation of amino acids. Endogenous sources of amino acids are secreted at high concentration into the small intestine. Most of the amino acids are absorbed as the content passes down the small intestine. Plasma amino acid concentrations are on the average only 1-5% of the concentrations in the duodunum. This is true even in rats on 24 hours of water and sugar with no exogenous sources of amino acids. For example, the PLASMA:DUODENUM concentrations (mumole/litre) are: Asparagine 37:7164, Tyrosine 94:9579, and glutamine/histidine 409:9708. This entero-portal recirculation of amino acids means the potential of a method for specific depletion of body amino acids by oral ingestion of bioreactants like immobilized enzymes. Preliminary studies used artificial cells to immobilize asparaginase,glutaminase and tyrosinase by microencapsulation. Six hours after 1 oral administration, asparagine, glutamine and tyrosine in the ileum were lowered to 10% of the level of the control. Artificial cells containing no enzymes were used as the control.

Implantable enzyme capsules for cancer chemotherapy from bakers' yeast cytosine deaminase immobilized on epoxy-acrylic resin and urethane prepolymer

For trial use in the local chemotherapy of cancer by a combination of cytosine deaminase (EC 3.5.4.1) and 5-fluorocytosine (J. Biotechnol., (1985), 2, 13-21), 40 U of partially purified cytosine deaminase was obtained from 500 g of commercial compressed bakers' yeast. The enzyme, which is unstable, was immobilized to stabilize it by the use of commercial epoxy-acrylic beads (Eupergit C). The immobilized enzyme was made into enzyme capsules with cellulose tubing for dialysis to encapsulate it or urethane polymer to entrap it, which materials are biocompatible. The activity of the intact cellulose capsules thus made was 0.4% that of the immobilized enzyme inside. The enzyme capsules also were stable. Ten days after the cellulose capsules were implanted in rats, 25% of the starting activity remained. When the polyurethane capsules were tested in vitro for 9 mo for thermostability at 37 degrees C, the activity decreased rapidly (with a half-life of 28 d) during the first 4 mo, and then slowly (half-life, about 100 d) during the next 5 mo. A calculation to transform the biphasic decline into a sum of the exponential decline of two components of enzymic activities with different strengths and half-lives showed that the larger half-life was 5 mo.

[Effect of biologically active dressings of wounds on the course of the wound process]

A comparative analysis of the effectiveness and expediency of the local application of collocyl (128 patients), trypsin immobilized on textile cellulose and kapron matrix (186 patients) and gauze bandage moistened with a solution of enzymes and 10% sodium chloride was made. It was shown that collocyl as well as trypsin modified gauze and kapron accelerated cleansing the wounds of nonviable tissues, decreased their infectivity, reduced intoxication of the organism and improved the course of the wound process.

[Immobilized papain in the treatment of acute destructive lactation mastitis]

Experience with the surgical treatment of 123 patients has shown the positive effect of proteolytic enzyme Papain immobilized on fiber polymer materials. It shortened the period of purification of purulent wounds of the lactating mammary gland from devitalized tissues which facilitated putting early secondary sutures on the granulating wound without a dissection of wound margins and resulted in quicker healing (13,5 days).

[Immobilized streptokinase (streptodecase) in the treatment of traumatic intra-ocular hemorrhage]

Streptodecase was used in experiments and in clinical practice for treatment of intraocular traumatic hemorrhages. The enzyme, at a dose of 30,000-45,000 .un, did not exhibit any toxico-allergic effects on eye tissues and caused maximal lysis of the blood clot. 114 patients were treated with the enzymatic preparation and in 60% of the patients blood, liberated into vitreous body, was completely lysed.

[Trypsin, immobilized on a textile cellulose matrix, in the treatment of suppurative wounds of soft tissue]

In the treatment of 328 patients trypsin immobilized on cellulose matrix was used in 110 patients, native enzymes were used in 148 patients and 70 patients were given means of physical antiseptics. The results have shown advantages of immobilized trypsin for the treatment of the wound process.

Acrylic microspheres in vivo VI: antitumor effect of microparticles with immobilized L-asparaginase against 6C3HED lymphoma

The antitumor effect of immobilized L-asparaginase was tested against lymphoid leukemia in mice with concomitant scanning of the L-asparagine level in serum. L-Asparaginase was immobilized in microspheres of polyacrylamide or polyacryldextran. These particles were used in C3H mice bearing the L-asparagine-dependent lymphoma (6C3HED). The tumor was maintained as an ascites tumor, 1 X 10(6) cells were injected intraperitoneally and on day 4 after inoculation, L-asparaginase was injected intramuscularly or intraperitoneally in microparticles. After injection of 5.0 IU ip of L-asparaginase in microparticles, partial remission was induced, generally, however, the cancer relapsed and killed the mice within 2-3 weeks. To obtain complete regression, it was necessary to inject 20 IU of L-asparaginase in microparticles intraperitoneally. The best therapeutic effect was obtained when the particles were administered intramuscularly. After injection of 5 IU the survival time was prolonged, but complete regression was not achieved. The best effect was obtained when the particles were given intramuscularly in two small doses (2.5 IU) at a 3-day interval. Such treatment induced complete regression; 10 out of 12 treated mice were completely cured and lived for several months. It is concluded that the L-asparagine level in serum has to be depressed to less than 20% of the normal level for at least 6-7 days to obtain complete regression of the tumor.

Acrylic microspheres in vivo V: Immunological properties of immobilized asparaginase in microparticles

L-Asparaginase was immobilized in microparticles of polyacrylamide. Such particles were then injected by intramuscular/subcutaneous, intraperitoneal, or intravenous routes into mice to investigate the immunological consequences of the immobilization. Entrapment of L-asparaginase in microparticles did not prevent the formation of antibodies in intensively treated animals. Intraperitoneal and intravenous injections of particles produced significantly higher antibody levels than soluble L-asparaginase. Antigen administered intramuscularly/subcutaneously in microparticles elicited, however, a weak immune response. Dependent on the route of administration, the particles may thus function as an adjuvant. A modified Arthus reaction in the foot pads of immunized mice indicated that antigenicity decreased when L-asparaginase was immobilized in microparticles. Injection of free L-asparaginase, intramuscularly/subcutaneously (2 x 20 IU) in the preimmunized mice produced no effects on the serum level of L-asparagine, whereas intramuscular/subcutaneous injection of L-asparaginase in microparticles produced a depression of the serum concentration. It is concluded that the intramuscular/subcutaneous injection of L-asparaginase in microparticles is the choice route of administration with respect to duration and the immunological reaction.

[Use of streptodecase in acute myocardial infarct]

This if the first time in the world that streptodecase has been used as a fibrinolytic drug during the first hours of clinical manifestations of myocardial infarction in 12 patients. The drug was given once, intravenously in the dose of 3,000,000 units. Favourable action of the drug on the clinical manifestations of the disease and its prolonged activating effect on the blood fibrinolysis have been established. The advantages of streptodecase over streptokinase in the treatment of acute myocardial infarction are discussed.

[Parenteral use of an immobilized microbial protease in the combined treatment of experimental peritonitis]

The experimental fecal peritonitis was induced in 70 immature rabbits and the effect of a new enzyme -- "immobilized" terrilythin -- and its combinations with ampicillin upon the development of the pathological process was studied. The efficiency of an associated repeated employment of the "immobilized" terrilythin and ampicillin in experimental peritonitis has been demonstrated which was supported by higher survival and longer life time of the experimental animals.