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S Blau

Publications and source records attributed to S Blau.

At least 19 recordsLinked to original sources
PubMed2001

Adsorption of cationized bovine serum albumin onto epithelial crypt fractions of the rat colon.

The purpose of the study was to characterize mucosal attachment of a cationized model protein, bovine serum albumin (BSA), onto the various fractions of colonic crypts epithelium in the rat. BSA was labeled with fluorescein isothiocyanate (FITC) and its surface net electric charge was modified from negative to positive. Attachment of the cationized protein (CF-BSA) onto rat colonic epithelium was performed by incubation of colonic everted sacs in medium containing cationized or non-cationized FITC-labeled BSA. Using a nonenzymatic isolation procedure, colonocytes were harvested from five horizontal fractions of the colonic crypts. BSA adhesion to the isolated colonocytes was quantified spectrofluorometrically. In addition, the effect of increasing concentrations of Mg(2+) on the adsorption of the cationized BSA onto the surface of colonic epithelium was evaluated by measuring its ability to displace the adhered BSA from its binding sites. BSA cationization facilitated protein adherence to the colon epithelium in a crypt depth-dependent manner. The largest extent of adherence was observed in the outer layer (first fraction) of the colon. Binding persisted to approximately half the depth of the crypts. The relation between CF-BSA concentration in the incubation medium and the amount of CF-BSA adsorbed onto the colonic epithelium was exponential in nature. The addition of electrolyte (Mg(2+)) caused a detachment of the CF-BSA. The adsorption process was characterized by Langmuir's adsorption isotherm. It is concluded that cationized BSA could be useful as a targetable drug platform in cases where the target site is the gastrointestinal epithelium.

Adsorption↗
PubMed2000

Relation between colonic inflammation severity and total low-molecular-weight antioxidant profiles in experimental colitis.

Tissue antioxidant status is altered as a response to oxidative stress. This oxidative stress, caused by reactive oxygen species, is associated with inflammatory bowel disease (IBD). Our aim was to examine the relationship between total tissue low-molecular-weight antioxidant (LMWA) profile and inflammation severity in dinitrobenzene sulfonic acid (DNBS) experimental colitis in the rat. Rats were treated with three doses of DNBS: 1, 10, and 20 mg. Inflammation severity was assessed by tissue colonic wet weight, macroscopic evaluation, and tissue myeloperoxidase (MPO) activity. The capacity of water-soluble LMWA was assessed by measuring the reducing power of the tissues with cyclic voltammetry (CV) and by measuring tissue levels of reduced glutathione. While typical markers of inflammation (MPO, macroscopic examination, and colonic wet weight) indicated DNBS dose dependency, such dependency could not be demonstrated for the tissue LMWA as measured by reduced glutathione levels and by the tissues' reducing power. Mild colonic inflammation (induced by ethanol or by 1 mg of DNBS) caused an increase in the overall capacity of water-soluble LMWA. However, severe inflammation (induced by 20 mg of DNBS) caused a reduction in the tissue LMWA capacity. An intermediate dose of DNBS (10 mg) caused moderate inflammation, but did not cause a significant change in the tissue LMWA compared with a saline control treatment. In conclusion, LMWA changed in a biphasic pattern reflective of the severity of mucosal colonic inflammation. It is suggested that: low dose of DNBS (1 mg) and topical alcohol (25% v/v) caused an adaptation effect to the mild oxidative stress associated with mild inflammation. This resulted in an increase in the LMWA. A higher dose of DNBS (20 mg) caused more severe inflammation with an overall reduction in LMWA. The increased efflux of reactive oxygen species, associated with severe inflammation, led to an overall consumption of the tissue LMWA, which masked the increase in LMWA caused by the mild oxidative stress.

Animals↗
PubMed2000

The effect of local attachment of cationized antioxidant enzymes on experimental colitis in the rat.

PURPOSE: To investigate the possibility of local treatment of colitis with the adhesive antioxidant enzymes catalase and superoxide dismutase (SOD). METHODS: The net electric charge of the enzymes' surfaces was modified from negative to positive, to cause their adherence to the colon epithelium. The effects of this local administration were assessed in inflamed rat colon. Inflammation severity (colitis) was assessed by measuring colonic tissue myeloperoxidase (MPO) activity, amounts of tumour necrosis factor alpha (TNFalpha) and concentrations of reduced glutathione (GSH). The measurements were carried out in two types of protocols: preventive (pre-colitis induction) and treatment (post-colitis induction). In addition, the efficacy of treatment with the cationized enzymes was compared to 5-aminosalicylic acid (5-ASA) and betamethasone with similar administration routes. RESULTS: The two cationized antioxidant enzymes were found to be efficient in both prevention and treatment of experimental colitis. The two cationized enzymes caused a significant reduction in MPO activity. A reduction in TNFalpha concentration was noted only after the treatment protocol. No correlation was found between inflammation severity and tissue levels of GSH. In most cases the cationized enzymes were more effective than 5-ASA and betamethasone. CONCLUSION: Cationized catalase and cationized SOD have the potential to be efficient therapeutic tools in the local treatment of colitis.

Animals↗
PubMed2000

Drug targeting by surface cationization.

Cationization of drug products and carriers involves a direct modification or attachment of conveying or accompanying components, either of which cause a charge modification. Cationization of macromolecules such as proteins and nucleotides and particulate drug carriers generally enhances their cellular uptake by endocytosis. The most common use of cationization today is in gene delivery. This is undertaken by either employing cationic polymers or entraping nucleotides in cationic carriers such as cationic liposomes. Cationized delivery systems are also used to overcome biological barriers and are suggested for drug targeting, in a nonspecific manner, to a variety of body organs, including brain, eyes, nose, and inflamed intestinal epithelium. Protein cationization is also suggested both for tumor immunotherapy and as a diagnostic tool in cancer therapy. Cationization has proven itself to be a straightforward tool for targeting to cells, tissues, and selected organs. This article reviews the extensive range of applications of cationization for improving drug and gene delivery and summarizes major technologies employed for that purpose.

Animals↗
PubMed1999

Differences in the reducing power along the rat GI tract: lower antioxidant capacity of the colon.

The ability of the gastrointestinal (GI) tract, as well as other tissues, to cope with reactive oxygen species (ROS) efflux in pathological events is determined partly by epithelial antioxidant levels. These levels are comprised of tissue antioxidant enzymes and low molecular weight antioxidants (LMWA). While glutathione levels and the activity of enzymatic antioxidants along the GI tract have been studied, the contribution of the overall LMWA to the total antioxidant capacity has not yet been determined. In this study the overall antioxidant activity in the mucosa/submucosa and muscularis/serosa of various sections along the small intestine and colon of the rat was evaluated by determining the reducing power, which reflects the total antioxidant activity derived from LMWA, using cyclic voltammetry. The activity of the antioxidant enzymes superoxide dismutase (SOD) and catalase was also measured. The reducing power (total antioxidant activity) was higher in the mucosa/submucosa of the small intestine as compared to the mucosa/submucosa of the colon. Similarly, catalase and SOD activity in the mucosa/submucosa of the small intestine was significantly higher than in the mucosa/submucosa of the colon. Differences were also observed in the reducing power and SOD activity in the muscularis/serosa of the rat small intestine as compared to the colon. The low antioxidant capacity in the colon may facilitate reactive oxygen species (ROS)-mediated injury and lead to inflammatory diseases such as ulcerative colitis, specifically in the colon.

Animals↗
PubMed1996

ARPP-21: murine gene structure and promoter identification of a neuronal phosphoprotein enriched in the limbic striatum.

ARPP-21 (cAMP-regulated phosphoprotein, Mr = 21,000 on sodium dodecyl sulfate polyacrylamide gel electrophoresis) is a phosphoprotein highly enriched in concentration in the neurons of the limbic striatum. It is likely a third messenger in the intracellular cascade of events following neuronal stimulation by first-messenger activators of the adenylate cyclase system, including dopamine via the D1 receptor. ARPP-21 expression is restricted to telencephalic post-mitotic, post-migrational neurons, and its precise pattern of temporal and spatial expression makes it an attractive candidate for the study of transcriptional regulation of neuronal maturation. To define genomic regions likely to contain functional promoter elements, we isolated the murine ARPP-21 gene. Primer extension and T2 RNase protection analyses identified multiple transcription start sites, but 1.3 kb of 5'-flanking DNA revealed few consensus transcription factor binding sequences. A series of transient transfection assays in clonal cell lines which do not express ARPP-21 identified a basal promoter active in both neuronal and non-neuronal lines. Expression in all lines was decreased by the inclusion of regions further upstream, and extinguished by the inclusion of the first intron. Further analyses are likely to reveal cell specific regulatory sequences.

Animals↗
PubMed1995

DARPP-32 promoter directs transgene expression to renal thick ascending limb of loop of Henle.

DARPP-32, a dopamine- and adenosine 3',5'-cyclic monophosphate (cAMP)-regulated inhibitor of protein phosphatase-1, is highly colocalized with neuronal and nonneuronal D1-type receptors. DARPP-32 concentration is enriched in the renal outer medulla and in the medium-size spiny neurons of the brain. In the ascending limb of the loop of Henle, DARPP-32 is phosphorylated following stimulation by dopamine and other first messengers, and in this form inhibits the activity of the Na(+)-K(+)-adenosinetriphosphatase pump. For functional analysis of the DARPP-32 promoter in the kidney, we characterized the murine gene. There are two groups of transcription start sites utilized in the brain, but the proximal set appears to be preferentially used in the kidney. In four of four lines of mice carrying a DARPP-32/lacZ transgene with 2.1 kb of 5'-flanking DNA, adult kidney lacZ transgene expression mimicked that of endogenous DARPP-32. There was no ectopic expression in peripheral organs. We conclude that the sequences necessary for direction of DARPP-32 expression to the medullary thick ascending limb are contained within this 2.1-kb fragment.

Animals↗
PubMed1993

Bioprosthetic cardiac valve degeneration: role of inflammatory and immune reactions.

Inflammatory and immune reactions are thought to mediate both calcification and biodegradation of bioprosthetic cardiac valve implants. To investigate the mechanisms of implant degeneration, we evaluated the role of inflammatory and immune reactions and the effects of tissue preservative treatment in three series of experiments. In the first experiment, three kinds of implants, i.e. glutaraldehyde-treated autograft Sprague-Dawley (SD) rat skin, xenograft Swiss-Webster (SW) mouse skin, and saline-treated autograft (control) were subcutaneously implanted in ten weanling SD rats, and retrieved after 70 days. There was no significant difference in the level of calcification in the autograft (113.13 +/- 27.09 micrograms/mg dry weight) and xenograft (78.27 +/- 31.53 micrograms/mg dry weight) (p > 0.05), but both differed significantly from the control specimens (1.55 +/- 0.87 micrograms/mg dry weight). In the second experiment, the immunological response to glutaraldehyde-treated bovine pericardium (glut tBP) and glycerol treated bovine pericardium (glyc tBP) implants were tested in vivo and in vitro. A Gore-Tex implant was used as a control. Sections of these materials were implanted to the abdominal muscle wall of Lewis rats, with each group composed of twelve animals. Lymphocytes and sera from the animals were isolated, and histological examination was performed at two or four weeks post-implantation. Collagen type 1 (calf skin) was used as antigen. Tritiated thymidine incorporation was used to measure lymphocyte response to antigen collagen type 1 (calf skin), and an Enzyme Linked Immunosorbent Assay (ELISA) was used to test antibodies. The results showed that lymphocytes from both the glut tBP and the glyc tBP groups responded to collagen type 1. The ELISA results showed that the glyc tBP group produced more antibodies than did the glut tBP group, with the difference being significant at a level of p < 0.02. Histology revealed that the glyc tBP had greater inflammatory changes and collagen degeneration than did the glut tBP. In the third experiment, sections of glut tBP and glyc tBP were implanted subcutaneously in two groups of ten weanling SD rats, and retrieved after 70 days. The results showed that glut tBP caused more calcification (197.04 +/- 83.56 micrograms/mg dry weight) than did the glyc tBP (6.74 +/- 0.55 microgram/mg dry weight), with the difference being significant at a level of p < 0.05. From these investigations it is concluded that tissue treatment prior to implantation was very important in determining the tendency of tissue to calcify, and that there was no obvious relationship between bioprosthetic calcification and immunogenicity.

Animals↗
PubMed1992

Amino acid levels during learning and memory consolidation of an aversive conditioning task in crickets.

We followed the titer of free amino acids in nervous ganglia and hemolymph of the cricket Pteronemobius sp. at different times during and after a shock avoidance training that included one experimental group and three controls. The results showed that Tau, urea, Thr, His, GABA, and an unidentified compound (Q) increased their titer in ganglia and hemolymph during training, whereas Ala, Arg, Val, Glu, Ser, and one or all of the group formed by Cys, Phe, Ile, Leu, and Trp decreased theirs concomitantly to memory consolidation. The difference in the rate of experimental insects and their yoked slaves to consolidate the learned task was reflected in the changes of the titers of the amino acids mentioned above. The data add to the evidence for a direct involvement of these amino acids in modulating the memory consolidation process.

Amino Acids↗
PubMed1992

A practical intervention programme aimed at decreasing high serum cholesterol levels in primary care.

A practical, primary care based intervention programme which aimed to lower serum cholesterol in a large percentage of hypercholesterolaemic subjects in general practice is described. Intervention consisted of a 8-10 minute interview supplying oral and written diet counselling. The programme was tried in a kibbutz (agricultural settlement) with 93 adult members: 89 had their serum cholesterol determined, 35 of whom (39%) were hypercholesterolaemic--19 had borderline high cholesterol (5.2-6.2 mmol/l), 16 had definitely high cholesterol (greater than or equal to 6.2 mmol/l). Repeat blood samples were taken from 33 of the 35 hypercholesterolaemic patients 6-9 months after exposure to the intervention programme. The initial cholesterol level of the hypercholesterolaemic group was 6.31 +/- 0.2 mmol/l (mean +/- SE): at follow up it was 5.3 +/- 0.2 mmol/l (P less than 0.001), a decrease in serum cholesterol (mean 22.2 +/- 2.1%) being seen in 28 of 33 patients (84%). In 19 patients (58%) cholesterol dropped to normal values, and in six additional cases (18%) it fell to borderline values. These data suggest that high cholesterol levels in otherwise normal adults may be reduced with little effort by the primary care physician and nurse.

Adult↗
PubMed1991

The phylogenic expression of plasmolipin in the vertebrate nervous system.

Plasmolipin is a plasma membrane proteolipid is a major myelin membrane component (Cochary et al., 1990). In this study we report the phylogenic expression of plasmolipin in the vertebrate nervous system. Using Western blot analysis with polyclonal antibodies, we have analyzed membrane fractions, including myelin, from elasmobranchs, teleosts, amphibians, reptiles, birds and mammals. On the basis of immune detection, plasmolipin appears to be restricted to the mammalian nervous system. Comparison of the central and peripheral nervous systems of mammals showed only minor differences in the level of plasmolipin in these two regions. Within mammals, little quantitative differences were observed when rat, human and bovine membrane fractions were compared. The late evolutionary expression of plasmolipin which results in its restriction to mammals makes it unique among the (major) myelin proteins. The potential physiologic significance of these data are discussed.

Amphibians↗
PubMed1990

Amino acids and memory consolidation in the cricket. I: Changes in the titer of free amino acids in nervous tissue after learning.

The involvement of certain amino acids in the memory consolidation process was investigated in the cricket Pteronemobius sp. Thirsty crickets were trained to constantly turn to one side of a symmetrical Y-shaped maze using reinforcement with water. Controls were trained to turn to both sides of the maze according to a random program. Animals were sacrificed immediately after training and free amino acid fractions were isolated from whole brain, subesophagic, prothoracic, mesothoracic and metathoracic ganglia homogenates and analyzed by high pressure liquid chromatography. A complex pattern of variation in the titer of amino acids emerged after learning, where the changes differed among the various ganglia. The most conspicuous change was an increase in the levels of urea and an amino acid-like compound related to the urea cycle, in all ganglia except the subesophagic one, if compared to controls. Arginine increased in the subesophagic ganglion, but decreased significantly in the metathoracic ganglion. The variation of ganglionic amino acid levels and its possible relation to mnemonic processes is discussed.

Amino Acids↗