Pharmacokinetics of kanamycin during targeted delivery to the liver in erythrocyte ghosts in animals with experimental acute cholecystitis

Pharmacokinetics of kanamycin was studied after its targeted delivery to the liver in autological erythrocyte ghosts on 25 noninbred dogs with experimental acute cholecystitis in comparison to the routine intravenous administration of the antibiotic in solution. Kanamycin concentrations in the tissues of the liver, pancreas, spleen, kidneys and lungs as well as in bile and blood serum were determined by the agar diffusion method 24, 48 and 72 hours after the last administration. It was found that the targeted delivery of kanamycin in blood shadows made it possible to provide high concentrations of the antibiotic for prolonged periods in the liver and biliary ducts and to more efficiently arrest the clinical manifestations of acute cholecystitis as well as normalize the laboratory indices. The data showed that using blood shadows as a reliable system for targeted delivery of antibiotics to the liver was advisable in purulent inflammatory affections of the biliary ducts.     

Organic-acid transport in resealed haemoglobin-containing human erythrocyte ''ghosts''.

The transport of organic acids across the membrane of resealed haemoglobin-containing erythrocyte 'ghosts' prepared by a dialysis technique has been studied. The present work forms part of studies directed towards the use of erythrocyte cellular carriers in enzyme-replacement therapy of inherited metabolic diseases. Oxalic acid, glycollic acid and glyoxylic acid were taken as representative of aliphatic acids of low molecular mass and benzoic and cinnamic acids as representative of unsubstituted aromatic acids. These selected acids are important in the diseases with which the present work is concerned. Comparison of influx and efflux transport characteristics showed that erythrocyte 'ghosts' retain transport properties closely similar to those of normal erythrocytes. Rapid transport was observed with all organic acids studied and there was a linear relationship between initial amount of influx and external concentration of aliphatic acid. Saturation of the transport system was not observed up to 1 mM external concentration, and the presence of plasma in the external medium had no effect on transport characteristics. Transport in intact erythrocytes and prepared erythrocyte 'ghosts' from patients with hyperoxaluria was also studied.     

Various aspects of the use of liposomes in the diagnosis, prophylaxis and treatment of infectious diseases

The literature data on preparation and properties of liposomes containing drugs, antigens and immunostimulants are reviewed. The efficiency of antibiotic-containing liposomal preparations in the treatment of infectious diseases has been demonstrated due to the directed transport of drugs into the target organs, inside cells, and to the decrease of antibiotics toxic effects. Immunostimulating and adjuvant effects of antigen-containing liposomes, particularly in combination with immunostimulants, have been described, that permits obtaining highly active diagnostic sera. The data are presented on the prospects for construction of molecular vaccines with the use of liposomes.     

Pyruvate and glucose transport through the erythrocyte membranes and the role of spectrin in these processes

Effect of antibody to peripheral protein spectrin and antibody to integral protein of band 3 on kinetic parameters of pyruvate and glucose transport in the pink erythrocyte ghosts has been studied. It is shown that spectrin structure reorganization induced by the antibody to this protein has different effect on pyruvate and glucose transport parameters. Band 3 protein modification with the help of the antibody to this protein changes pyruvate transport parameters, while glucose transport is not changed. The data obtained show that facilitated diffusion of glucose and anions in the erythrocyte membrane is carried out by different carriers, the action of these carriers essentially depending on the structure state of spectrin.     

Methodologic aspects of the x-ray endoscopic study of the pancreatobiliary system]

Methodological variants of roentgenoendoscopic investigation of the pancreatobiliary system were worked out on the basis of a combination of various methods of contrast studies of the ducts and fibroduodenoscopy. Possibilities of their use were shown with respect to a clinical situation. Investigations of 240 patients led to the conclusion that the use of the above variants of roentgenoendoscopic investigation increased diagnostic and therapeutic efficacy in diseases of the pancreatobiliary system.     

Visualization of the biliary tract; preoperative and post-operative radiologic investigation

Modern operative treatment of diseases of the bile passages requires the use of x-ray visualization of the biliary tract before, after and during operation. Nearly every surgeon uses x-ray study of the biliary tract before operation and it is widespread practice to carry out such study after operations in which a tube has been placed in the bile passages. However, there is a remarkable aversion to operative cholangiography.The usual reasons for avoiding operative cholangiography are unfamiliarity, inertia, concern over complications of the technique, and the feeling that it is unnecessary or wasteful of surgeon's time and patient's money. Yet the results of operative cholangiograms compare favorably with those obtained with the more customary x-ray studies of the bile ducts carried out after operation, at a time when the information gained is much less valuable in avoiding additional operations and in contributing to a smooth and rapid convalescence.     

Breast cancer resistance protein (BCRP/ABCG2) is expressed by progenitor cells/reactive ductules and hepatocytes and its expression pattern is influenced by disease etiology and species type: possible functional consequences.

Breast cancer resistance protein (BCRP/ABCG2) is an ATP-binding cassette transport protein that is expressed in several organs including the liver. Previous studies have shown that ABC transport proteins play an important pathophysiological role in several liver diseases. However, to date, expression pattern and possible role of BCRP in human liver diseases and animal models have not been studied in detail. Here we investigated the expression pattern of BCRP in normal liver, chronic parenchymal and biliary human liver diseases, and parallel in different rat models of liver diseases. Expression was studied by immunohistochemistry and additionally by RT-PCR analysis in Thy-1-positive rat oval cells. Bile ducts, hepatic progenitor cells, reactive bile ductules, and blood vessel endothelium were immunoreactive for BCRP in normal liver and all types of human liver diseases and in rat models. BCRP was expressed by the canalicular membrane of hepatocytes in normal and diseased human liver, but never in rat liver. Remarkably, there was also expression of BCRP at the basolateral pole of human hepatocytes, and this was most pronounced in chronic biliary diseases. In conclusion, BCRP positivity in the progenitor cells/reactive ductules could contribute to the resistance of these cells to cytotoxic agents and xenotoxins. Basolateral hepatocytic expression in chronic biliary diseases may be an adaptive mechanism to pump bile constituents back into the sinusoidal blood. Strong differences between human and rat liver must be taken into account in future studies with animal models.     

VISUALIZATION OF THE BILIARY TRACT—Preoperative,Operative and Postoperative Radiologic Investigation

Modern operative treatment of diseases of the bile passages requires the use of x-ray visualization of the biliary tract before, after and during operation. Nearly every surgeon uses x-ray study of the biliary tract before operation and it is widespread practice to carry out such study after operations in which a tube has been placed in the bile passages. However, there is a remarkable aversion to operative cholangiography.The usual reasons for avoiding operative cholangiography are unfamiliarity, inertia, concern over complications of the technique, and the feeling that it is unnecessary or wasteful of surgeon''s time and patient''s money. Yet the results of operative cholangiograms compare favorably with those obtained with the more customary x-ray studies of the bile ducts carried out after operation, at a time when the information gained is much less valuable in avoiding additional operations and in contributing to a smooth and rapid convalescence.     

Direct cholangiography: its diagnostic and therapeutic role.

In the management of biliary tract disorders, direct cholangiography should be chosen over ultrasonic examination if the bile ducts are thought to be obstructed. Contrast medium can be introduced into the bile ducts either percutaneously or retrogradely via the ampulla of Vater, the choice of technique often depending on the clinical situation. Direct access to the biliary tree for diagnostic purposes has also led to advances in the treatment of mechanical disorders of the ducts.     

Application of mesenchymal stem cell exosomes and their drug‐loading systems in acute liver failure

Stem cell exosomes are nanoscale membrane vesicles released from stem cells of various origins that can regulate signal transduction pathways between liver cells, and their functions in intercellular communication have been recognized. Due to their natural substance transport properties and excellent biocompatibility, exosomes can also be used as drug carriers to release a variety of substances, which has great prospects in the treatment of critical and incurable diseases. Different types of stem cell exosomes have been used to study liver diseases. Due to current difficulties in the treatment of acute liver failure (ALF), this review will outline the potential of stem cell exosomes for ALF treatment. Specifically, we reviewed the pathogenesis of acute liver failure and the latest progress in the use of stem cell exosomes in the treatment of ALF, including the role of exosomes in inhibiting the ALF inflammatory response and regulating signal transduction pathways, the advantages of stem cell exosomes and their use as a drug‐loading system, and their pre‐clinical application in the treatment of ALF. Finally, the clinical research status of stem cell therapy for ALF and the current challenges of exosome clinical transformation are summarized.     

Clinical and economic expedience of ertapenem therapy of complicated urinary tract infection

Clinical and economic investigation of various antibiotics use in the treatment of complicated urinary tract infection (CUTI) was performed under the Russian economic environment. The drugs of comparison were ertapenem, ceftriaxone and levofloxacin. Direct costs and their structure were shown, and the cost efficiency was calculated. Alternative analysis and one-side susceptibility analysis were performed. In complicated urinary tract infections when the major pathogens were Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis it was clinically and economically reasonable to start the treatment with ceftriaxone or ertapenem, while levofloxacin could be an alternative strategy. When the effects of the acquired resistance on the treatment effectiveness were evaluated (SIS model) it was shown that the pathogens susceptibility to ertapenem was preserved for a significantly longer time than that to ceftriaxone or levofloxacin (60 months). Such a parameter may serve as an additional evidence of the reasonable use of ertapenem as the starting treatment of CUTI.     

Expression of neural cell adhesion molecule in human liver development and in congenital and acquired liver diseases

In the liver, neural cell adhesion molecule (NCAM) is a marker of immature cells committed to the biliary lineage and is expressed by reactive bile ductules in human liver diseases. We investigated the possible role of NCAM in the development of intrahepatic bile ducts and aimed at determining whether immature biliary cells can contribute to the repair of damaged bile ducts in chronic liver diseases. Therefore, we performed immunohistochemistry for NCAM and bile duct cell markers cytokeratin 7 and cytokeratin 19 on frozen sections of 85 liver specimens taken from 14 fetuses, 10 donor livers, 18 patients with congenital liver diseases characterized by ductal plate malformations (DPMs), and 43 cirrhotic explant livers. Duplicated ductal plates and incorporating bile ducts during development showed a patchy immunoreactivity for NCAM, while DPMs were continuously positive for NCAM. Bile ducts showing complete or patchy immunoreactivity for NCAM were found in cirrhotic livers, with higher frequency in biliary than in posthepatitic cirrhosis. Our results suggest that NCAM may have a function in the development of the intrahepatic bile ducts and that NCAM-positive immature biliary cells can contribute to the repair of damaged bile ducts in chronic liver diseases.     

Membrane transport in resealed haemoglobin-containing human erythrocyte 'ghosts' prepared by a dialysis procedure

Resealed haemoglobin-containing erythrocyte ‘ghosts’ have been proposed as $\text{in}\text{vivo}$ carriers for enzyme replacement therapy. Transport of substrates and metabolites into and out of the ‘ghost’ has been suggested to be a limiting factor in such therapy. Studies of the transport of L-phenylalanine and of uric acid in normal human erythrocytes and prepared ‘ghosts’, in which the transport of sodium ions and D-glucose was intact, have shown that transport characteristics of ‘ghosts’ are identical to those of normal erythrocytes with transport not being a quantitatively limiting factor.     

真菌性鼻-鼻窦炎研究进展

真菌性鼻-鼻窦炎是鼻科临床常见的一种特异性感染性疾病。传统观点认为,真菌性鼻-鼻窦炎(fungalrhino-sinusitis,FRS)多在机体长期使用抗生素、糖皮质激素、免疫抑制剂及接受放射治疗等情况下发生,也可在一些慢性消耗性疾病如糖尿病、烧伤致机体抵抗力下降时发生。但近年来在健康体检中也有发现FRS,造成这种情况的原因目前还不太清楚,有待进一步研究。由于引起致病的病原真菌种类不同,真菌性鼻窦炎的临床类型、诊断、治疗及临床疗效果等均有各自的特点,以下针对病因、临床类型及表现、诊断、治疗及预后等方面进行回顾。     

Serological diagnosis of suppurative-septic diseases of staphylococcal etiology

The parallel examination of osteomyelitis patients by means of the passive hemagglutination (PHA) test with the use of antigenic erythrocyte diagnostic agents, prepared on the basis of hydrochloric acid extract from Staphylococcus aureus strain 209P and teichoic acid extract from S. aureus strain Wood 46 has revealed that these diagnostic agents are practically equal in their diagnostic effectiveness. In the examination of endocarditis patients measurement of the total antibody activity in the PHA test with diagnosticum on the basis of strain 209P has proved to be a more sensitive method, whereas in osteomyelitis patients the total IgG activity has been more accurately measured by ELISA. The treatment of sera with 2-mercaptoethanol essentially decreased the diagnostic effectiveness of the PHA test. The study has shown the diagnostic value of not only IgG but also of IgM antibody measurements.     

Regulation of intrahepatic biliary duct morphogenesis by Claudin 15-like b

The intrahepatic biliary ducts transport bile produced by the hepatocytes out of the liver. Defects in biliary cell differentiation and biliary duct remodeling cause a variety of congenital diseases including Alagille Syndrome and polycystic liver disease. While the molecular pathways regulating biliary cell differentiation have received increasing attention (Lemaigre, 2010), less is known about the cellular behavior underlying biliary duct remodeling. Here, we have identified a novel gene, claudin 15-like b (cldn15lb), which exhibits a unique and dynamic expression pattern in the hepatocytes and biliary epithelial cells in zebrafish. Claudins are tight junction proteins that have been implicated in maintaining epithelial polarity, regulating paracellular transport, and providing barrier function. In zebrafish cldn15lb mutant livers, tight junctions are observed between hepatocytes, but these cells show polarization defects as well as canalicular malformations. Furthermore, cldn15lb mutants show abnormalities in biliary duct morphogenesis whereby biliary epithelial cells remain clustered together and form a disorganized network. Our data suggest that Cldn15lb plays an important role in the remodeling process during biliary duct morphogenesis. Thus, cldn15lb mutants provide a novel in vivo model to study the role of tight junction proteins in the remodeling of the biliary network and hereditary cholestasis.     

Isolation of Neonatal Extrahepatic Cholangiocytes

The intra and extrahepatic bile ducts of the liver are developmentally distinct, and may be differentially affected by certain diseases. However, differences between intra and extrahepatic cholangiocytes, and between neonatal and adult cells, are not well understood.Methods for the isolation of cholangiocytes from intrahepatic bile ducts are well established^1-4. Isolation of extrahepatic ductal cells, especially from the neonate, has not yet been described, although this would be of great benefit in understanding the differences between distinct cholangiocyte populations and in studying diseases such as biliary atresia that appear to target the extrahepatic ducts. Described here is an optimized technique to isolate both neonatal and adult mouse extrahepatic bile duct cells. This technique yields a pure cell population with minimal contamination from mesenchymal cells like fibroblasts.This method is based on the removal of the extrahepatic ducts and gallbladder, followed by meticulous dissection and scraping to remove fat and fibroblast layers. Structures are embedded in thick layers of collagen and cultured for approximately 3 weeks to allow outgrowth of cholangiocytes in monolayers, which can then be trypsinized and re plated for experimental use.     

Liposomal-delivery of phosphodiesterase 5 inhibitors augments UT-15C-stimulated ATP release from human erythrocytes

The use of liposomes to affect targeted delivery of pharmaceutical agents to specific sites may result in the reduction of side effects and an increase in drug efficacy. Since liposomes are delivered intravascularly, erythrocytes, which constitute almost half of the volume of blood, are ideal targets for liposomal drug delivery.In vivo, erythrocytes serve not only in the role of oxygen transport but also as participants in the regulation of vascular diameter through the regulated release of the potent vasodilator, adenosine triphosphate (ATP). Unfortunately, erythrocytes of humans with pulmonary arterial hypertension (PAH) do not release ATP in response to the physiological stimulus of exposure to increases in mechanical deformation as would occur when these cells traverse the pulmonary circulation. This defect in erythrocyte physiology has been suggested to contribute to pulmonary hypertension in these individuals.In contrast to deformation, both healthy human and PAH erythrocytes do release ATP in response to incubation with prostacyclin analogs via a well-characterized signaling pathway. Importantly, inhibitors of phosphodiesterase 5 (PDE5) have been shown to significantly increase prostacyclin analog-induced ATP release from human erythrocytes.Here we investigate the hypothesis that targeted delivery of PDE5 inhibitors to human erythrocytes, using a liposomal delivery system, potentiates prostacyclin analog- induced ATP release. The findings are consistent with the hypothesis that directed delivery of this class of drugs to erythrocytes could be a new and important method to augment prostacyclin analog-induced ATP release from these cells. Such an approach could significantly limit side effects of both classes of drugs without compromising their therapeutic effectiveness in diseases such as PAH.     

Liposomes in the Treatment of Parasitic,Viral, Fungal and Bacterial Infections

Abstract

The applicability of liposomes as carriers of immunomodulatory agents or antibiotics for improvement of treatment of severe infections is under investigation. The use of “classical'’ liposomes for targeting of macrophage modulators to enhance non-specific host resistance to infections caused by a variety of micro-organisms shows good results. The therapeutic prospects of “classical'’ liposomes as carriers of antibiotics are good, however are limited to the treatment of intracellular infections in mononuclear phagocyte system (MPS) tissues. The recent development of liposome formulations with reduced affinity to the MPS and long circulation half-lives creates new possibilities for obtaining improved delivery of antibiotics to infected tissues in general including infections in non-MPS tissues.     

Current progress of siRNA/shRNA therapeutics in clinical trials

Through a mechanism known as RNA interference (RNAi), small interfering RNA (siRNA) molecules can target complementary mRNA strands for degradation, thus specifically inhibiting gene expression. The ability of siRNAs to inhibit gene expression offers a mechanism that can be exploited for novel therapeutics. Indeed, over the past decade, at least 21 siRNA therapeutics have been developed for more than a dozen diseases, including various cancers, viruses, and genetic disorders. Like other biological drugs, RNAi-based therapeutics often require a delivery vehicle to transport them to the targeted cells. Thus, the clinical advancement of numerous siRNA drugs has relied on the development of siRNA carriers, including biodegradable nanoparticles, lipids, bacteria, and attenuated viruses. Most therapies permit systemic delivery of the siRNA drug, while others use ex vivo delivery by autologous cell therapy. Advancements in bioengineering and nanotechnology have led to improved control of delivery and release of some siRNA therapeutics. Likewise, progress in molecular biology has allowed for improved design of the siRNA molecules. Here, we provide an overview of siRNA therapeutics in clinical trials, including their clinical progress, the challenges they have encountered, and the future they hold in the treatment of human diseases.