The antibiofilm effects of Byotrol™ G32.

AIM: The purpose of this study was to evaluate a commercial antimicrobial formulation, Byotrol™ G32, as a potential coating for impeding biofilm formation on medical devices such as urinary catheters. METHODS AND RESULTS: The antimicrobial activity of Byotrol™ G32 and its individual constituents has been tested on planktonic and biofilm cultures of uropathogenic bacteria. The Byotrol™ G32 formulation was superior with MICs ranging from 3 µg ml(-1) to 15 µg ml(-1) for planktonic cultures and 3-20 µg ml(-1) for biofilms. Furthermore, Byotrol™ G32 was able to remove established biofilms and act as an antibiofilm surface coating. CONCLUSIONS: Byotrol™ G32 displays impressive antimicrobial activity both in suspension and as a coating. Pretreating medical devices with Byotrol™ G32 may significantly impede biofilm formation and prolong the lifetime of the device. SIGNIFICANCE AND IMPACT OF THE STUDY: Medical devices are indispensable in health care. They are, however, a predisposing factor in infection. This research has demonstrated that Byotrol™ G32 reduces bacterial growth and subsequent biofilm formation. Application of Byotrol™ G32 as a medical device coating could have a significant impact on the costs associated with device replacement and patient morbidity and mortality.

Sodium chloride increases the ciliary transportability of cystic fibrosis and bronchiectasis sputum on the mucus-depleted bovine trachea.

Mucus retention in the lungs is an important feature of several respiratory diseases (Regnis, J.A., M. Robinson, D.L. Bailey, P. Cook, P. Hooper, H.K. Chan, I. Gonda, G. Bautovich, and P.T.P. Bye. 1994. Am. J. Respir. Crit. Care Med. 150:66-71 and Currie, D.C., D. Pavia, J.E. Agnew, M.T. Lopez-Vidriero, P.D. Diamond, P.J. Cole, and S.W. Clarke. 1987. Thorax. 42:126-130). On the mucus-depleted bovine trachea, the ciliary transport rate of sputum from patients with cystic fibrosis and bronchiectasis of other causes was slow, but the rate was doubled by increasing the sodium chloride content by 90 mM. Increasing the sputum osmolality by inspissation or by the addition of nonelectrolytes had a similar effect. The viscoelasticity of sputum, but not the bovine ciliary beat frequency, was markedly saline dependent over the pathophysiological range. This suggests that low mucus salinity, not (as is generally assumed) its under-hydration, contributes to its retention in bronchiectasis due to cystic fibrosis and other causes, probably by affecting its rheology. It also indicates how the genetic defect in cystic fibrosis might lead to impaired mucus clearance. Therapies that increase the osmolality of lung mucus might benefit patients with mucus retention.

Protective mechanism of Lygodium flexuosum extract in treating and preventing carbon tetrachloride induced hepatic fibrosis in rats.

The protective effect of Lygodium flexuosum extract in preventive and curative treatments of CCl(4) induced fibrosis was quantified. Hepatic fibrosis was induced in male Wistar rats by CCl(4) administration (150 microL/100 gm rat weight, oral) twice a week for 10 weeks. In preventive treatment daily doses of L. flexuosum n-hexane extract (200 mg/kg, p.o) were administered for 10 weeks. In curative treatment L. flexuosum extract (200 mg/kg, p.o) was given for 2 weeks after the establishment of fibrosis for 10 weeks. Treatment with the n-hexane extract (200 mg/kg) reduced the mRNA levels of proinflammatory cytokines, growth factors and other signaling molecules, which are involved in hepatic fibrosis. The expression levels of tumor necrosis factor-alpha, interleukin-1beta, transforming growth factor-beta1, procollagen-I, procollagen-III and tissue inhibitor of metalloproteinase-1 were elevated during carbon tetrachloride administration and reduced the levels to normal by the treatment with the extract treatment. The increased levels of matrix metalloproteinase-13 in extract treated rats were indicative of the protective action of L. flexuosum n-hexane extract. In conclusion, L. flexuosum n-hexane extract functions as a potent fibrosuppresant, effectively reverses carbon tetrachloride-induced hepatic fibrosis in curative treatment and reduces the effects of ongoing toxic liver injury in preventive treatment by promoting extracellular matrix degradation in the fibrotic liver.

Hepatoprotection of Phyllanthus maderaspatensis against experimentally induced liver injury in rats.

The hexane extract of Phyllanthus maderaspatensis (200 and 100 mg/kg) showed significant hepatoprotection on carbon tetrachloride and thioacetamide induced liver damage in rats. The protective effect was evident from serum biochemical parameters and histopathological analysis. Rats treated with P. maderaspatensis remarkably prevented the elevation of serum AST, ALT and LDH and liver lipid peroxides in CCl(4) and thioacetamide treated rats. Hepatic glutathione levels significantly increased by the treatment with the extracts. Histopathological changes induced by CCl(4) and thioacetamide were also significantly reduced by the extract treatment. The activity of hexane extracts of P. maderaspatensis was comparable to that of silymarin, the reference hepatoprotective drug.

Antiangiogenic effect of Lygodium flexuosum against N-nitrosodiethylamine-induced hepatotoxicity in rats.

The antiangiogenic effect of Lygodium flexuosum extract was evaluated in Wistar rats intoxicated with N-nitrosodiethylamine (NDEA) in preventive and curative models. In preventive groups, NDEA was administered for 20 weeks. Daily doses of L. flexuosumn-hexane extract (200mg/kg) started 1 week before the onset of NDEA intoxication and continued for 20 weeks. In curative animals, NDEA was administered for 20 weeks followed by treatment with the n-hexane extract of L. flexuosum for 28 days. Rats intoxicated with NDEA had elevated levels of serum gamma-GT, AST, ALT, LDH levels and hepatic MDA and decreased levels of hepatic GSH. When treated with L. flexuosum extract had normal levels of gamma-GT, AST, ALT, LDH levels, hepatic MDA and GSH. NDEA administered rat liver showed an overexpressed levels of angiopoietins 1 (Ang-1) and 2 (Ang-2) and its receptor Tie-2 mRNA. L. flexuosum extract treatment significantly (p

Inhaled hyperosmolar agents for bronchiectasis.

BACKGROUND: Mucus retention in the lungs is a prominent feature of bronchiectasis. The stagnant mucus becomes chronically colonised with bacteria, which elicit a host neutrophilic response. This fails to eliminate the bacteria, and the large concentration of host-derived protease may contribute to the airway damage. The sensation of retained mucus is itself a cause of suffering, and the failure to maintain airway sterility probably contributes to the frequent respiratory infections experienced by many patients. Hypertonic saline inhalation is known to accelerate tracheobronchial clearance in many conditions, probably by inducing a liquid flux into the airway surface, which alters mucus rheology in a way favourable to mucociliary clearance. Inhaled dry powder mannitol has a similar effect. Such agents are an attractive approach to the problem of mucostasis, and deserve further clinical evaluation. OBJECTIVES: To determine whether inhaled hyperosmolar substances are efficacious in the treatment of bronchiectasis SEARCH STRATEGY: The Cochrane Airways Group Specialised Register was searched, and leaders in the field were contacted. Searches were current as of October 2005. Search updates will be run annually. SELECTION CRITERIA: Any trial using hyperosmolar inhalation in patients with bronchiectasis not caused by cystic fibrosis. DATA COLLECTION AND ANALYSIS: Two reviewers assessed studies for suitability. MAIN RESULTS: Two small studies met the inclusion criteria of the review (28 participants). One study reported tracheobronchial clearance of a particulate radio aerosol after inhalation of dry mannitol on a single occasion, with appropriate control. Airway clearance doubled in the central and intermediate regions of the lung, but not in the peripheral region, after mannitol administration. No side effects were observed, but two patients were premedicated with nedocromil to prevent bronchospasm. Findings from one further trial indicated that one domain of a sensitive health status instrument showed a favourable response to mannitol. AUTHORS' CONCLUSIONS: Dry powder mannitol has been shown to improve tracheobronchial clearance in bronchiectasis, as well as cystic fibrosis, asthmatics, and normal subjects. Hypertonic saline has not been specifically tested in bronchiectasis, but improves clearance in these other conditions and in chronic bronchitis. The measurement of health status in one of the studies should be repeated in future longer term randomised controlled studies of mannitol and hypertonic saline. Consideration should also be given to exacerbations and symptom scores, as well as drug-related adverse events.

Protective effect of Lygodium flexuosum (L.) Sw. extract against carbon tetrachloride-induced acute liver injury in rats.

The hepatoprotective potential of Lygodium flexuosum (L.) Sw. was evaluated in male Wistar rats against carbon tetrachloride-induced liver damage in preventive and curative models. Toxic control and n-hexane extract-treated rats received a single dose of CCl4 (150 microL/100g, 1:1 in corn oil). Pre-treated rats were given n-hexane extracts at 200 and 100 mg/kg dose 48, 24 and 2 h prior to CCl4 administration. In post-treatment groups, rats were treated with n-hexane extract at a dose of 200 and 100 mg/kg, 2, 24 and 48 h after CCl4 intoxication. Rats pre-treated with Lygodium flexuosum remarkably prevented the elevation of serum AST, ALT, LDH and liver lipid peroxides in CCl4-treated rats. Rats treated with the extract after the establishment of CCl4 induced liver injury showed significant (p < or = 0.05) protection of liver as evidenced from normal AST, ALT, LDH and MDA levels. Hepatic glutathione levels were significantly (p < or = 0.05) increased by the treatment with the extracts in both the experimental groups. Histopathological changes induced by CCl4 were also significantly (p < or = 0.05) reduced by the extract treatment in preventive and curative groups. Phytochemical studies revealed the presence of saponins, triterpenes, sterols and bitter principles in Lygodium flexuosumn-hexane extract which could be responsible for the possible hepatoprotective action.

Protective effect of Lygodium flexuosum (L.) Sw. (Lygodiaceae) against D-galactosamine induced liver injury in rats.

The protective effect of Lygodium flexuosum n-hexane extract against D-galactosamine was evaluated in Wistar rats. In preventive groups extract was administered at 48, 24 and 2h before D-galactosamine intoxication whereas in post-treatment groups extract were administered 2, 24 and 48 h after D-galactosamine intoxication. Rats pre-treated with n-hexane extract at a dose of 200 and 100 mg/kg of Lygodium flexuosum showed a significant prevention of elevated AST, ALT, LDH levels and hepatic malondialdehyde in D-galactosamine treated rats. Hepatic glutathione levels significantly upregulated by the extract treatment in D-galactosamine treated rats. Quantification of histopathological sections supported the preventive action of n-hexane extract of Lygodium flexuosum. Rats treated with the extract at a dose of 200 and 100 mg/kg Lygodium flexuosum after the establishment of D-galactosamine induced liver injury showed complete protection of liver as evidenced from normal AST, ALT and LDH levels, hepatic GSH and MDA levels and also by normal histological index of liver in treated rats. Rats treated with n-hexane extract of Lygodium flexuosum were comparable to that of Silymarin, the standard hepatoprotective drug.

Preventive and curative effect of Lygodium flexuosum (L.) Sw. on carbon tetrachloride induced hepatic fibrosis in rats.

The preventive and curative effect of Lygodium flexuosum on experimentally induced hepatic fibrosis by carbon tetrachloride (CCl(4)) was evaluated in rats. Hepatic fibrosis was induced in male Wistar rats by CCl(4) administration (150 microL/100g rat weight, oral) twice a week for 10 weeks. In preventive treatment daily doses of Lygodium flexuosum n-hexane extract (200 mg/kg, p.o) was administered for 10 weeks. In curative treatment Lygodium flexuosum extract (200 mg/kg, p.o) was given for 2 weeks after the establishment of fibrosis for 10 weeks. Treatment with CCl(4) caused a significant decrease in body and liver weight. Lygodium flexuosum n-hexane extract prevented or reversed the decline in body and liver weight. Treatment with the extract prevented or restored the elevation of serum AST, ALT and LDH levels. Lygodium flexuosum treatment remarkably prevented or reversed an increase in liver hydroxyproline content in chronically treated rats. Histopathological changes of hepatic lesions induced by CCl(4) were significantly (p < or = 0.05) improved by treatment with Lygodium flexuosum. These results support that Lygodium flexuosum exerts effective protection in carbon tetrachloride induced hepatic fibrosis in rats.

Metabolic heterogeneity in rabbit brain glycogen.

Glycogen has been carefully isolated from rabbit brain tissue and found to be of significantly greater molecular size (up to approx. 100 MDa) and heterogeneity than previously reported. The incorporation of radioisotope from glucose, pyruvate or acetate precursor has been shown to be non-uniform, being similar to the metabolic inhomogeneity observed in other tissues. Physicochemical studies have shown the gross hydrodynamic structure of the glycogen to be inhomogeneous and to differ significantly from that of liver glycogen.

Stem loops in HIV and prion protein mRNAs.

Tat-dependent trans-activation in HIV requires presentation of a CUGGG pentanucleotide at the end of a stem loop within the tar site of the viral long terminal repeat. A tandem repeat within the open reading frame of the prion protein (PrP) mRNA is able to form similar stem loop structures with which the HIV tat protein could interact, disturbing PrP translation. Self-amplification of such a disturbance has been suggested as the cause of the scrapie group of diseases, including the scrapie-like human dementiae. The same mechanism may underly AIDS encephalopathy.

Effect of salmeterol on human nasal epithelial cell ciliary beating: inhibition of the ciliotoxin, pyocyanin.

1. Patients with airway infection by Pseudomonas aeruginosa have impaired mucociliary clearance. Pyocyanin is a phenazine pigment produced by P. aeruginosa which is present in the sputum of colonized patients, slows human ciliary beat frequency (CBF) in vitro and slows mucociliary transport in vivo in the guinea-pig. 2. We have investigated the effect of salmeterol, a long-acting beta 2-adrenoceptor agonist, on pyocyanin-induced slowing of human CBF in vitro. Salmeterol (2 x 10(-7) M) was found to reduce pyocycanin (20 micrograms ml-1)-induced slowing of CBF by 53% and the fall in intracellular adenosine 3':5'-cyclic monophosphate (cyclic AMP) by 26% and ATP by 29%. 3. Another beta 2-adrenoceptor agonist, isoprenaline (2 x 10(-7) M), also inhibited pyocyanin-induced slowing of CBF by 39%. 4. The effects of salmeterol (30 min preincubation) persisted after washing the cells. 5. Propranolol (10(-7) M) and the beta 2-specific antagonist, ICI 118551 (10(-6) M) blocked the protective effects of salmeterol completely, but atenolol (10(-6) M) was less effective. These results suggested that the effects of salmeterol on pyocyanin-induced effects were mediated primarily via the stimulation of beta 2-adrenoceptors. 6. Pyocyanin-induced ciliary slowing is associated with a substantial fall in intracellular cyclic AMP and ATP. Salmeterol reversed the effects of pyocyanin on cyclic AMP and ATP. 7. Mucociliary clearance is an important defence mechanism of the airways against bacterial infection. Salmeterol may benefit patients colonized by P. aeruginosa, not only by its bronchodilator action, but also by protecting epithelial cells from pyocyanin-induced slowing of CBF.

Differential inhibition of the human cell DNA replication complex-associated DNA polymerases by the antimetabolite 1-beta-D-arabinofuranosylcytosine triphosphate (ara-CTP).

The antimetabolite 1-beta-D-arabinofuranosylcytosine (ara-C) has been used as a highly effective agent for the treatment of leukemia. The active metabolite 1-beta-D-arabinofuranosylcytosine triphosphate (ara-CTP) is a potent inhibitor of DNA polymerases alpha, delta, and epsilon, and is responsible for inhibiting intact cell DNA synthesis. We have shown that a multiprotein complex, exhibiting many of the properties expected of the human cell DNA replication apparatus, can be readily isolated from human cells and tissues and is capable of supporting origin-dependent DNA synthesis in vitro. DNA polymerases alpha, delta, and epsilon are components of this multiprotein complex, termed the DNA synthesome, and we report here that the activities of these DNA synthesome-associated DNA polymerases are inhibited differentially by ara-CTP. Inhibition of the DNA synthesome-associated DNA polymerase alpha increased in a concentration-dependent manner, and was correlated closely with the inhibition of simian virus 40 (SV40) origin-dependent in vitro DNA replication, whereas DNA synthesome-associated DNA polymerase delta activity was not inhibited significantly by ara-CTP at 100 microM. Recent work has shown that the synthesome-associated DNA polymerase epsilon does not function in in vitro SV40 DNA replication, suggesting that only polymerases alpha and delta drive the DNA replication fork. Therefore, our results suggest that inhibition of the activity of the mammalian cell DNA synthesome by ara-CTP is due primarily to the inhibition of the DNA synthesome-associated DNA polymerase alpha. This observation implies that the drug may target specific phases of the DNA synthetic process in human cells.

The structure of placental glycogen.

Glycogen was purified from human term placenta and its structural features investigated. The beta-amylolysis limit and average chain lengths indicated that some degradation of the glycogen had occurred prior to its extraction. The sedimentation coefficient distribution of the purified glycogen showed that it contained a significant proportion of aggregated material. Diffusion coefficient measurements allowed calculation of the molecular weight distribution. The placental glycogen contained a significant proportion of high molecular weight material, although not as much as liver or skeletal muscle glycogens. Because the high molecular weight glycogen of liver and skeletal muscle is associated with the lysosome it is likely that this is also true of the large placental glycogen. Lysosomal glycogen is degraded hydrolytically to glucose and so placental glycogen may be involved in fetal glucose homeostasis.

Use of cardiovascular drugs in an older Swedish population.

OBJECTIVE: To describe the use of cardiovascular drugs in an older population with respect to age, sex, housing type, and creatinine clearance. DESIGN: A cross-sectional survey. PARTICIPANTS: All residents of a district of Stockholm (Kungsholmen), Sweden, aged 75 and older, living in institutions or at home. MEASUREMENTS: Cardiovascular drug use, serum creatinine, electrolytes, height, weight, and symptoms. RESULTS: A total of 43 cardiovascular (CV) drugs were used. The most common drugs were digoxin (used by 18.2%), furosemide (16.4%), and glyceryl trinitrate (12.4%). Drugs with an antihypertensive effect accounted for 61% of all CV drugs. CV drug use increased with age for cardiac glycosides and diuretics, but decreased with age for calcium antagonists and beta-blockers. Drug doses tended to be less than the recommended daily dose except for a few drugs, e.g., furosemide. There was a trend toward decreasing dose with increasing age, but this was not significant. Diuretics were the only CV drugs used more often in women. People living in institutional care used the least amount of CV drugs. The dose of drugs taken did not appear to be related to estimated creatinine clearance. Comparisons between drug use and complaint of symptoms showed a strong correlation between the use of cardiac glycosides and anorexia, calcium antagonists and constipation, and nitrates and vertigo. There were weaker correlations with cardiac glycosides and visual disturbances and with potassium sparing diuretics and a high potassium. CONCLUSIONS: CV drugs are used commonly in older people. We suggest that the symptoms correlating with cardiac glycoside use may be signs of unrecognized toxicity, and this may relate to our finding that drug use is often not tailored to renal function as measured by creatinine clearance.

Isolation of Chlamydia using McCoy cells and Buffalo green monkey cells.

Unselected eye and genital specimens from 233 patients were cultured for Chlamydia. The isolation rates were compared using McCoy cells and Buffalo green monkey cells, both procedures being performed with and without the addition of cycloheximide and centrifugation. No significant difference was found in the isolation rates using the four methods. The characteristics of the two cell lines and the advantages of omitting cycloheximide treatment and centrifugation are discussed.

Ara-C differentially affects multiprotein forms of human cell DNA polymerase.

PURPOSE: The antimetabolite 1-beta-D-arabinofuranosylcytosine (ara-C) has proven to be one of the most effective agents available for the treatment of acute leukemia although the precise mechanism by which ara-C induces cytotoxicity remains unclear. Our laboratory has previously isolated from human cells a DNA replication complex, termed the DNA synthesome, which is fully competent to orchestrate, in vitro, all of the reactions required to efficiently and faithfully replicate DNA. Using this system and the active metabolite of ara-C, ara-CTP, we demonstrated that the human DNA synthesome can efficiently incorporate ara-CTP into internucleotide positions of newly replicated DNA in vitro mimicking results obtained using intact cells and isolated nuclei. We then hypothesized that DNA polymerase auxiliary proteins, present within the DNA synthesome, may aid in incorporating this nucleotide analog into DNA. METHODS: To test this hypothesis, we utilized three distinct multiprotein complexes each of which contained human DNA polymerase alpha and examined with standard in vitro polymerase assays the effectiveness of ara-C in inhibiting various aspects of their polymerase function. RESULTS AND CONCLUSION: These polymerase-mediated elongation assays, which included ara-CTP- or ara-C-containing primers in the reaction mixture, showed that the rate of DNA elongation in the presence of ara-CTP was significantly enhanced when the DNA polymerase was associated with its auxiliary proteins, and that the elongation resulted in the formation of internucleotide ara-CMP. Nevertheless, the enhanced activities resulting from the association of these auxiliary proteins with polymerase alpha did not fully account for the remarkable efficiency with which the DNA synthesome incorporated ara-C into internucleotide positions during DNA replication.

A novel in vitro model system for studying the action of ara-C.

The antimetabolite 1-beta-D-arabinofuranosyl-cytosine (ara-C) has proven to be one of the most effective agents available for the treatment of acute leukemia. While ara-C has been implicated as a potent inhibitor of mammalian cell DNA replication, the specific mechanism by which ara-C kills cells is not known. In this report we describe the development of an in vitro model system to study the molecular mechanism of ara-CMP incorporation into DNA. This model system makes use of a recently described human cell multiprotein DNA replication complex (MRC) that is competent to replicate DNA in vitro. The MRC can successfully incorporate ara-CMP into replicating DNA at internucleotide positions. These results are similar to those described for studies using intact cells. This MRC-driven in vitro replication system may therefore serve as a powerful model for the study of anticancer agents that directly affect human cell DNA synthesis.

Effects of thermodynamic nonideality on protein interactions. Equivalence of interpretations based on excluded volume and preferential solvation.

Published results on the stabilization of proteins by sucrose (J.C. Lee and S.N. Timasheff, J. Biol. Chem. 256 (1981) 7193) have been reexamined and interpreted in terms of thermodynamic nonideality. The composition dependence of activity coefficients may be accounted for on a statistical-mechanical basis using the concept of excluded volume. An expression is derived in which the effect of sucrose on determination of the partial specific volume of a protein, previously interpreted in terms of preferential protein solvation, is also seen to be attributable to excluded volume. Gel chromatographic studies of the reversible unfolding of alpha-chymotrypsin are presented which demonstrate temperature- and sucrose-mediated changes in the effective volume of the enzyme. These measurements support the quantitative interpretation of the stabilization in terms of thermodynamic nonideality arising from the difference between covolumes for sucrose and the two isomeric states of alpha-chymotrypsin. By establishing the equivalence of the two approaches that have been used to account for the effects of inert solutes on protein transitions, the present investigation eliminates the need for any distinction between such solutes on the basis of molecular size; and also enhances greatly the potential sensitivity of thermodynamic nonideality as a means of probing protein isomerizations, since greater displacement of the equilibrium position may be effected by small rather than by macromolecular solutes present at the same weight concentrations.

Excluded-volume effect of inert macromolecules on the melting of nucleic acids.

It is shown on the basis of the excluded-volume effect that inert macromolecules may be expected to suppress the dissociation of double-helical nucleic acids into single helices and thus to raise the melting point of the double helix. The rise in melting temperature of the ribonucleic acid [poly(I).poly(C)] caused by dextran polymers and by poly(ethylene oxide) is described and compared with the theoretical prediction. Good agreement was found in respect of the extent of the rise in melting point and in respect of its dependence upon polymer length. An additional dependence upon the identify of the polymer was attributed to detailed effects of shape in solution.