High Molecular Weight Substances Research Articles

Identification and characterisation of biofilm formed on membrane bio-reactor

Experiments were conducted in a laboratory scale membrane bio-reactor (MBR) system equipped with a side stream flat sheet membrane. Six runs lasting different durations (2, 4, 6, 9, 15 and 20 days) were conducted at an aeration rate of 2 m 3 h −1 m −2 to understand the temporal variation of chemistry of foulant that attached on the membrane surface. The foulant attached on the membrane surface was extracted with 0.5% (v/v) NaOH solution and the extract was analysed using fluorescent spectroscopy and size exclusion chromatography. Variation of low- and high-molecular weight substances with evolution of time was compared. The results showed that the nature of foulant changed with the evolution of time. Four runs conducted for a short duration (2, 4, 6 and 9 days), low-molecular weight substances were dominant in the foulant whereas for long duration runs (15 and 20 days), high-molecular weight substances were mainly observed. Moreover, the foulant close to the membrane surface contained mainly protein and soluble microbial by-products.

Female mating receptivity inhibited by injection of male-derived extracts in Callosobruchus chinensis

The effects of male-derived extracts on female receptivity to remating were investigated in Callosobruchus chinensis (Coleoptera: Bruchidae). Injection of aqueous extracts of male reproductive tracts into the abdomen of females reduced receptivity. When aqueous extracts of male reproductive tracts were divided to three molecular weight (MW) fractions by ultrafiltration: <3, 3–14, and >14kDa, the filtrate containing MW substances <3kDa reduced female receptivity 3h and 1 day after injection, whereas the fraction containing MW substances >14kDa inhibited receptivity 2 and 4 days after injection. Finally, male reproductive tract organs were divided into accessory gland, seminal vesicle, and testis. Aqueous extracts of testis reduced receptivity of females on the second day and at 3h, and aqueous extracts of accessory gland reduced receptivity of females on the second day after injection. On the other hand, aqueous extracts of seminal vesicle did not reduce female receptivity. The results indicate that more than one mechanism may be involved in producing the effects of male-derived substances on female receptivity; low MW male-derived substances, which possibly exist in testis, cause short-term inhibition, while high MW substances, which possibly exist in the accessory gland, inhibit female mating later than low MW substances in C. chinensis.

Subcellular distribution of trace elements in kidney of a mother–fetus pair of Dall’s porpoises ( Phocoenoides dalli)

Total and subcellular renal Zn, Cu, Se, Mn, V, Hg, Cd and Ag were determined by a mother–fetus pair of Dall’s porpoises ( Phocoenoides dalli). All element concentrations in the maternal individual were higher than those in the fetal individual. Most of total renal elements studied were present in the cytosol of both animals. In maternal cytosol, Mn, Hg and Ag were present in high molecular weight substances (HMW); Se was in low molecular weight substances (LMW); Zn, Cu, and Cd were in metallothionein (MT), mostly; and the distribution of V in percentage among the three renal cytosolic fractions was similar. In fetal cytosol, Zn, Mn, Hg, V, Cd, and Ag were present in HMW, Cu was present in MT, mostly. In contrast, Se was observed mostly in both LMW and HMW. MT isoforms were characterized. Three obvious peaks in retention time were found in either the maternal or fetal MT. The highest elemental ion intensities were in the 7.8 min peak for the mother, and in the 4.3 min peak for the fetus, respectively, implying that different MT isoforms may be closely associated with elemental accumulation between maternal and fetal renal cytosols.

Total and subcellular distribution of trace elements (Cd, Cu and Zn) in the liver and kidney of green turtles ( Chelonia mydas) from the Mediterranean Sea

This study investigated the subcellular distribution of Cd, Cu and Zn in liver and kidney of green turtles ( Chelonia mydas) stranded along the Italian coast of the South Adriatic Sea (Eastern Mediterranean). Cd and Zn mean concentrations did not differ significantly between liver (4.26 μg g −1 and 34.53 μg g −1, respectively) and kidney (5.06 μg g −1 and 26.39 μg g −1, respectively), whereas the levels of Cu were significantly higher in liver (32.75 μg g −1) than in kidney (8.20 μg g −1) ( p < 0.009). Most of Cd, Cu and Zn was present in hepatic and renal cytosol, and their concentrations increased with total levels in both organs, indicating that cytosol has a crucial role in metal accumulation. Cd and Cu in hepatic and renal cytosol were present mostly in metallothionein fractions (MTs), whereas Zn was fractionated into MTs and high-molecular-weight-substances (HMWS). The comparison with the results of other investigations on individuals of the same species collected in different marine areas shows good agreement relatively to essential metals. For Cd our data are comparable with those encountered in specimens from the Mediterranean Sea (Cyprus) confirming the homogeneity of the area comprising the south-eastern basin of the Mediterranean Sea from an ecological point of view.

Tetrodotoxin-binding proteins isolated from five species of toxic gastropods

Toxic gastropods Polinices didamy, Natica lineata, Oliva miniacea, O. mustelina and O. hirasei are tetrodotoxin (TTX) bearing animals, which accumulate TTX in their muscle and digestive gland. Analysis by gel filtration on Sepharose CL-6B revealed that 0.05 M NaCl extracts of the muscle of five species of toxic gastropods contained TTX-binding high molecular weight substances (HMWS) (1500–2000 kDa). The TTX-binding capacities of those HMWS were 0.12, 0.62, 0.45, 0.28 and 0.35 MU/mg protein, respectively, but those HMWS had no neutralising effect on TTX or paralytic shellfish poison. The HMWS of the five toxic gastropods could be hydrolyzed with HCl and protease at 37 °C, pH 7.4, but not with ribonuclease T2, deoxyribonuclease I or α-amylase. After purifying the TTX-binding protein of N. lineata by Q Fast-Flow strong anion exchanger and then BioSep-SEC-S 2000, the TTX-binding capacity increased to 3.5 MU/mg and 4.2 MU/mg protein, respectively. The TTX-binding capacity of N. lineata HMWS had no obvious seasonal variation. The molecular weight of TTX-binding protein of N. lineata was estimated to be about 434 kDa, while it comprised two subunits with molecular weights of about 272 kDa and 47 kDa, respectively, under SDS–PAGE.

Impact of Double-Filtration Plasmapheresis in Combination with Interferon and Ribavirin in Living Donor Liver Transplant Recipients with Hepatitis C

Double-filtration plasmapheresis (DFPP) selectively removes high molecular weight substances including hepatitis C virus (HCV). Four live donor liver transplantation (LDLT) recipients with HCV received combination therapy with low-dose interferon (IFN) and ribavirin with DFPP. Three patients underwent this therapy for prophylaxis of HCV recurrence, and one for treating fibrosing cholestatic hepatitis (FCH). The combination therapy and DFPP decreased HCV RNA levels to 8.2% +/- 2.9% and 0.7% +/- 0.5% by the 5th and 30th day of treatment, respectively. Three patients who underwent DFPP for prophylaxis showed no evidence of HCV recurrence for >1 year after treatment. The patient whose graft showed FCH, recovered dramatically after the DFPP treatment. DFPP appeared to be effective in reducing HCV viremia and preventing HCV recurrence in patients with high HCV RNA levels after LDLT. Moreover, it may become a rescue therapy for FCH in a liver transplant recipient with hepatitis C.

Immunomodulatory activity of polysaccharides isolated from Salicornia herbacea

Several types of immunomodulatory polysaccharides originated from plants or mushrooms have been used as immunotherapeutic agents in the treatment of cancers. Here, we describe an immunomodulatory polysaccharide that cannot only activate monocytic cells strongly, but also induce differentiation of monocytic cells into macrophages. High molecular weight substances, SHE, were isolated from Salicornia herbacea, which has been used to treat a variety of diseases including cancers in traditional oriental remedy. The immunomodulatory activities of SHE were examined on a mouse monocytic cell line, RAW 264.7 cells. We found that SHE activated RAW cells to produce cytokines such as tumor necrosis factor (TNF)-α and interleukin (IL)-1β, and nitric oxide (NO) dose dependently. SHE also induced the expression of co-stimulatory molecules such as B7-1 and CD40, and increased phagocytic activity on opsonized sheep red blood cells. While increasing these parameters of macrophage activation, SHE inhibited the growth of RAW cells dose dependently inducing morphological changes from slightly adherent monocytic cells to strongly adherent macrophages. The active components of SHE appeared to be polysaccharides, and not an endotoxin. These results show that polysaccharides originated from S. herbacea possess potent immunomodulatory activity on monocyte/macrophage lineage cells.

Effect of asphaltene and resin oils on the viscosity of bituminous petroleum materials to be used as asphalt primers

The bituminous crude from the Machete, Venezuela, area, which has such a fluid consistency that it falls outside the normal scope of the A5TM D-5 (1) penetration test exceeding the 3D-mm ceiling specified in that standard and can be used as an asphalt primer: Like other asphalt products, these materials are -chemically speaking- a mix of numerous naphthenic, paraffinic and aromatic hydrocarbons and heterocyclic compounds containing sulphur, nitrogen, oxygen and so on. They have a dense and a malthene oil phase which, along with the natural hydrocarbons additives used in these products acts as a volatile fluidizer. The former is described as a mix of asphaltenes: complex high molecular weight substances that are insoluble in paraffinic hydrocarbons and soluble in aromatic compounds such as benzene. The malthene oil phase, in turn, consists in a mix of resins and hydrocarbons and together the two constitute a colloidal system. The experiments discussed in the present paper were conducted to determine the effect of the proportion of asphaltenes and resin oils on the viscosity of such bituminous crude emulsions/ with a view to their use as primers. These experiments were run in a Parr batch reactor in a nitrogen atmosphere using n-heptane as a solvent. The resins were separated after the asphaltenes precipitated from the samples and subsequently from the malthene fraction obtained. The results showed that the asphaltenes account for the structural characteristics and consistency of the medium and the resin oils for its cohesive properties/,the malthene oils act as solvents.

Dissolved organic matter (DOM) in recycled leachate of bioreactor landfill

Landfill leachate needs sufficient treatment before safe disposal. Bioreactor landfill technology could effectively degrade the organic matters in recirculated leachate, hence leaving a leachate stream of low biodegradability. This study characterized the dissolved organic matter (DOM) in the leachate from simulated bioreactor landfill columns with or without presence of trace oxygen. The removal efficiencies of this DOM using coagulation–sedimentation or electrolysis processes were demonstrated. Recirculated leachates were sampled from the simulated landfill columns applying conventional mode, intermittent-aeration mode, and natural aeration mode, whose DOM was fractionated into humic acids (HA), fulvic acids (FA) and hydrophilic fractions (HyI) by the XAD-8 resin combined with the cation exchange resin method. The recirculated leachate had low BOD/COD ratio, high humic substances contents, and high aromatic content. Their HA fraction comprised mainly large molecules (>10 k Da), while the FA and HyI were composed of smaller molecules (<50 k and <4 k Da, respectively). With the presence of oxygen, the TOC contents and the contents of HA, FA and HyI in leachate reduced, with FA and HyI fractions of molecular weight (MW) lower than 4 k Da more readily degraded. The organic matters left in leachates from intermittent-aeration mode and natural aeration mode were of low biodegradability. It was tested in the following sections the effects of coagulation–sedimentation process and of electrolysis process on the removal of residual DOM in recirculated leachate. Coagulation–sedimentation tests revealed that poly ferric sulphate (PFS) could remove more COD (58.1%) from leachate than polyaluminum chloride (PACl) (22.9%), particularly on the HA fraction with MW>10 k Da. Coagulation–sedimentation could not remove most of HyI in leachate. Furthermore, the corresponding BOD/COD ratio was not improved through coagulation. Electrolysis test could also effectively removed HA of MW>10 k Da. However, the biodegradability of treated effluent considerably was improved. The electrolysis could decompose high MW substances and increase biodegradability of recirculated leachate from bioreactor landfill.

Urinary macromolecules and renal tubular cell protection from oxalate injury: Comparison of normal subjects and recurrent stone formers

To determine whether urinary macromolecules (UMM), which are the high molecular weight substances in urine, can provide protection against the oxalate-associated injury to the renal tubular cells. UMM were extracted from 24-h urine of 12 healthy adult male volunteers and 13 recurrent-stone-former male patients. Urine parameters in relation to urolithiasis were measured, including the level of glycosaminoglycans (GAG) in the UMM. Madin-Darby canine kidney (MDCK) cells were used to evaluate the protective activity of UMM from oxalate-induced cytotoxicity by LDH release measurement and methyl-thiazolyl tertrazolium (MTT) assay. Considering urinary parameters, citrate was significantly higher in urine from normal subjects than stone-former subjects; the other parameters show no differences between the groups. Total UMM and the level of GAG in the UMM were also significantly higher in the normal subject group. Compared with normal subject and stone-former subject UMM, after cells were treated with the UMM and then exposed to oxalate solution, LDH release was significantly higher in stone-former group. In the MTT assay, we found that more viable cells were observed after treatment with UMM compared to control in both groups. Moreover, UMM from the normal subjects showed higher protective activity against oxalate-related cytotoxicity than UMM from the stone-former subjects. UMM protected renal epithelial cells from oxalate-related injury. This protective activity was found to be higher in normal subject UMM than stone-former UMM. Among other factors, a higher concentration of GAG and citrate in normal subject UMM might affect some parts in this finding.

Clinical effects of online dialysate and infusion fluids

Online hemodiafiltration appears to be the most effective technique of renal replacement therapy in many respects. Removal of small and high-molecular weight substances is enhanced. Modern technology ensures a safe, online production of reinfusion fluids. Nonetheless, stringent maintenance rules are required for the production of sterile and nonpyrogenic-dialysate solutions. In this review, we will critically review the state of the art of the clinical effects derived from the use of ultrapure dialysate and the online production of dialysate fluids in high-flux hemodiafiltration.

Organization of the pronephric filtration apparatus in zebrafish requires Nephrin, Podocin and the FERM domain protein Mosaic eyes

Podocytes are specialized cells of the kidney that form the blood filtration barrier in the kidney glomerulus. The barrier function of podocytes depends upon the development of specialized cell–cell adhesion complexes called slit-diaphragms that form between podocyte foot processes surrounding glomerular blood vessels. Failure of the slit-diaphragm to form results in leakage of high molecular weight proteins into the blood filtrate and urine, a condition called proteinuria. In this work, we test whether the zebrafish pronephros can be used as an assay system for the development of glomerular function with the goal of identifying novel components of the slit-diaphragm. We first characterized the function of the zebrafish homolog of Nephrin, the disease gene associated with the congenital nephritic syndrome of the Finnish type, and Podocin, the gene mutated in autosomal recessive steroid-resistant nephrotic syndrome. Zebrafish nephrin and podocin were specifically expressed in pronephric podocytes and required for the development of pronephric podocyte cell structure. Ultrastructurally, disruption of nephrin or podocin expression resulted in a loss of slit-diaphragms at 72 and 96 h post-fertilization and failure to form normal podocyte foot processes. We also find that expression of the band 4.1/FERM domain gene mosaic eyes in podocytes is required for proper formation of slit-diaphragm cell–cell junctions. A functional assay of glomerular filtration barrier revealed that absence of normal nephrin, podocin or mosaic eyes expression results in loss of glomerular filtration discrimination and aberrant passage of high molecular weight substances into the glomerular filtrate.

Multielemental accumulation and its intracellular distribution in tissues of some aquatic birds

This study was aimed at determining multielemental concentration and its intracellular distribution in selected tissues of cormorant and waterfowl species. Non-essential elements such as Hg, Tl, Cd, Pb and V in tissues were generally consistent with those in ingested items, indicating the significance of food sources of non-essential metal accumulation in great cormorants and mallards. Great cormorants and four waterfowl species examined reflected natural background levels of toxic metals such as Cd, Hg and Pb as well as some essential elements, indicating no specific metal exposure from local sources. Most of Cu, Zn, Se, Rb, Ag, Cd, Cs, and Hg contents were present in the hepatocytosolic fraction, whereas a large percentage of V and Mo were present in insoluble fraction in great cormorant, mallard, and spot-billed duck. The major role of these subcelluar fractions in elemental regulation accounts for the high percentage contribution of each cellular fraction to the total metal contents. Cadmium and Cu are chiefly sequestered through binding to metallothioneins (MTs) of hepatocytosolic fraction in these three avian species. Both MTs and high-molecular-weight substance (HMWS) for Zn and low-molecular-weight substance (LMWS) for Rb were also involved in their sequestration in cytosolic fractions. Relatively different species-specific cytosolic substances were responsible for varying degrees of Ag, Mn, and Co accumulation. It is worth noting that these intracellular metal levels in birds are closely regulated by metal-associated cellular constituents. Therefore, risk assessment studies of metal accumulation in such wild birds should take intracellular metal distribution and specific cellular constituents into account.

Sequential Convective Therapies (SCT): A Prospective Study on Feasibility, Safety, Adequacy and Tolerance of On-Line Hemofiltration and Hemodiafiltration in Sequence

Sequential dialysis techniques (i.e pure ultrafiltration followed by dialysis) have been used in the past, due to their capability to remove large volumes of fluids without inducing hemodynamic instability. The disadvantages of inadequate efficiency and lack of technology lead to the decline of such methods. Hemofiltration (HF) and hemodiafiltration (HDF) are recently being utilized in a greater proportion thanks to on-line fluid preparation systems. Each process (HF and HDF) has its own benefits in the removal of small, medium and high-molecular weight substances and in hemodynamic stability. Sequential convective therapies (SCT) such as hemofiltration-hemodiafiltration in sequence (HF-HDF) may combine the benefits and eliminate the disadvantages of each method and should be studied in order to explore their potential application in modern dialysis. Furthermore they can be easily applied nowadays, due to the development of new sophisticated dialysis machines. In order to evaluate the feasibility, safety, efficiency and tolerance of different SCT methods we studied 3 schedules: SCT1: 1h pre-dilution HF followed by 3h of post-dilution HDF (in the HF mode we lost 25% of the total fluid that had to be removed). SCT2: 1h pre-dilution HF followed by 3h of post-dilution HDF (in the HF mode we lost 50% of the total fluid that had to be removed). SCT3: 2h pre-dilution HF followed by 2h of post-dilution HDF (in the HF mode we lost 50% of the total fluid that had to be removed). We studied 6 chronic hemodialysis patients using the same machine (AK200 ULTRA), with on-line fluid preparation system and the same type of dialyzer (Polyflux 210). SCT schedules were compared to on-line HF, on-line HDF and high flux dialysis performed with the same dialyzers. The treatments resulted safe, easy, feasible and well tolerated with an improved hemodynamic response to high volume convective therapies. Adequacy of treatment was satisfactory in all SCT schedules while middle molecular weight solute clearance and removal resulted higher in treatments with higher convective component. SCT might represent an interesting option for the future especially in patients with hemodynamic instability and requirements for interventions during treatment.

Approaches to the study and description of metal cation binding on functional fragments of high-molecular weight substances in aqueous systems

The main approaches to the study and description of equilibria of metal cation and proton binding by a high-molecular weight substance in aqueous systems were analyzed in the case of scarce information on binding sites. Almost all the approaches have substantial disadvantages, especially from the viewpoint of model verification, informativeness, and opportunities of meaningful interpretations of the results obtained. A specific approach to a combined estimation of both binding constants and concentrations of binding sites was recommended. This approach uses experimental data only on the degree of complex formation and makes it possible to enhance significantly the informativeness of research of the state of heavy metals and a high-molecular weight organic substance interacting with the heavy metals in natural waters.

Approaches to the study and description of metal cation binding on functional fragments of high-molecular weight substances in aqueous systems

Approaches to the study and description of metal cation binding on functional fragments of high-molecular weight substances in aqueous systems

Modern Auxiliary Substances in Tablet Production: Use of High-Molecular-Weight Compounds for the Development of New Medicinal Forms and Optimization of Technological Processes

Scientifically justified selection of high-quality auxiliary components in solid dosed medicinal forms, in particular tablets, is an important factor influencing the competitiveness of drugs on the market, which is determined not only by their direction of action and urgent necessity, but also by the quality level and the quality-to-price ratio. An important role in the development of modern high-quality dosed solid medicinal forms and optimization of their production technology is played by high-molecular-weight (HMW) compounds, which make it possible to create preparations with preset biopharmaceutical and technological properties. At present, a new generation of such auxiliary HMW components available from foreign manufacturers is widely used in Russian pharmacy. A broad spectrum of new synthetic polymer matrices intended for the controlled release of parent substances from tablets provides conditions for the optimum realization of biological activity of drugs having various structures and directions of action. The use of crosslinked polymeric superdisintegrants ensures a significant increase in the bioaccessibility of poorly soluble parent substances, while retaining the mechanical properties of tablets on a sufficiently high level. The use of new universal HMW substances as auxiliary components combining several functions also creates prerequisites for optimization of the technological process. An increase in the assortment of auxiliary HMW components provides for the development of tablet production technology and ensures an increase in the quality of products.

Association of heavy metals with metallothionein and other proteins in hepatic cytosol of marine mammals and seabirds.

Distribution of Cu, Zn, Cd, Ag, Hg, and Se were determined in hepatocytosol of northern fur seals (Callorhinus ursinus), black-footed albatrosses (Diomedea nigripes), and Dall's porpoises (Phocoenoides dalli). Copper, Zn, and Cd were accumulated preferentially in metallothionein (MT) fraction and their contents in MT fraction increased with the amounts in the hepatocytosol. Silver was bound to both high-molecular-weight substances (HMWS) and MT in the hepatocytosol for all three species, whereas the distribution of Ag in the cytosol was different among the three species. In northern fur seals, Ag mainly was bound to MT, whereas it mainly was associated with HMWS in Dall's porpoises. In contrast, Ag was distributed almost equally in both HMWS and MT for black-footed albatrosses. Mercury content in HMWS and Se content in HMWS and low-molecular-weight substances (LMWS) increased with their contents in hepatocytosol for all the three species. A significant positive correlation was found between Se and Hg contents in high-molecular weight (HMW) fraction in cytosol. The molar ratio of Hg and Se was close to unity in HMW fraction of the specimens with high Hg concentration in cytosol, implying that the Hg-Se complex was bound to the HMWS. Analysis of metals in the hepatocytosol by high-performance liquid chromatography/inductively coupled plasma-mass spectrometry (HPLC/ICP-MS) suggests that multiple isoforms of MT are present in hepatocytosol of the three species and that the metal profiles in hepatocytosols are different among the species. To our knowledge, this is the first report on the association of Ag with HMWS and MT in hepatocytosol of marine mammals and seabirds. Also, distribution and interaction of Hg and Se were investigated for the first time in hepatocytosol of the higher trophic marine animals.

Royal jelly inhibits the production of proinflammatory cytokines by activated macrophages.

In this study, we have examined the anti-inflammatory actions of royal jelly (RJ) at a cytokine level. When supernatants of RJ suspensions were added to a culture of mouse peritoneal macrophages stimulated with lipopolysaccharide and IFN-gamma, the production of proinflammatory cytokines, such as TNF-alpha, IL-6, and IL-1, was efficiently inhibited in a dose-dependent manner without having cytotoxic effects on macrophages. This suggests that RJ contains factor(s) responsible for the suppression of proinflammatory cytokine secretion. We named the factor for honeybees RJ-derived anti-inflammatory factor (HBRJ-AIF), and further investigated the molecular aspects of it. Size fractionation study showed that HBRJ-AIF is composed of substances of low (< 5 kDa) and high (> 30 kDa) molecular weights, with the former being a major component. Chromatographic analysis showed that MRJP3 is one candidate for the HBRJ-AIF with high molecular weights. Thus, our results suggest that RJ has anti-inflammatory actions through inhibiting proinflammatory cytokine production by activated macrophages.

Protein-bound uremic retention solutes

Protein-bound uremic retention solutes are molecules with low molecular weight (MW) but should be considered middle or high MW substances. This article describes the best known substances of this group, which include p-cresol, indoxyl sulfate, hippuric acid, 3-carboxy-4-methyl-5-propyl-2-furan-propionic acid (CMPF), and homocysteine. At concentrations encountered during uremia, p-cresol inhibits phagocyte function and decreases leukocyte adhesion to cytokine-stimulated endothelial cells. CMPF has been implicated in anemia and neurologic abnormalities of uremia. CMPF could alter the metabolism of drugs of inhibiting their binding to albumin and their tubular excretion. Indoxyl sulfate administrated to uremic rats increases the rate of progression of renal failure. Hippuric acid inhibits glucose utilization in the muscle, and its serum concentration is correlated with neurologic symptoms of uremia. Homocysteine predisposes uremic patients to cardiovascular disease throughimpairment of endothelial and smooth muscle cell functions. The removal of protein-bound compounds by conventional hemodialysis is low. Other strategies to decrease their concentrations include increase in dialyze pore size, daily hemodialysis, peritoneal dialysis, reduction of production or acceleration of degradation, and preservation of residual renal function.