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The miRNA complex with Argonaute protein recognizes and down-regulates target mRNA. The role of interorganellar interactions in controlling miRNA activity in mammalian macrophages infected with Leishmaniais explored.

Cholestatic jaundice is a well recognised complication of late sepsis. However, cholestatic liver injury preceding sepsis is less well known and appreciated. This leads to delays in diagnosis in clinical practice and may result in significant morbidity and mortality. The development of a cholestatic blood picture should be considered as an early warning sign of an underlying infection, even in the absence of signs or symptoms of sepsis. This report describes the case of a previously healthy patient who presented with cholestatic jaundice. Staphylococcal osteomyelitis involving the left sacroiliac joint was diagnosed. Literature relating to cholestatic jaundice in sepsis is reviewed.

A miscible homopolymer–copolymer pair viz., poly(ethyl methacrylate) (PEMA)–poly(styrene-co-butyl acrylate) (SBA) is reported. The miscibility has been studied using differential scanning calorimetry. While 1 : 1 (w/w) blends with SBA containing 23 and 34 wt % styrene (ST) become miscible only above 225 and 185 °C respectively indicating existence of UCST, those with SBA containing 63 wt % ST is miscible at the lowest mixing temperature (i.e., Tg's) but become immiscible when heated at ca 250 °C indicating the existence of LCST. Miscibility for blends with SBA of still higher ST content could not be determined by this method because of the closeness of the Tg's of the components. The miscibility window at 230 °C refers to the two copolymer compositions of which one with the lower ST content is near the UCST, while the other with the higher ST content is near the LCST. Using these compositions and the mean field theory binary interaction parameters between the monomer residues have been calculated. The values are χST-BA = 0.087 and χEMA-BA = 0.013 at 230 °C. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 369–375, 2000

Import of tRNA into Leishmania mitochondria involves transfer through a double membrane barrier. To examine whether specific sorting mechanisms for individual tRNAs direct them to different mitochondrial compartments, the distribution of tRNA transcripts, internalized in vitro, was examined by suborganellar fractionation. Significant amounts of tRNA(Tyr) were localized in the matrix and on the outer face of the inner mitochondrial membrane. With time, the matrix:membrane ratio increased. Translocation through the inner membrane apparently required the presence of a specific signal in the D arm of tRNA(Tyr), and tRNA(Gln)(CUG), lacking this sequence, was excluded. Hydrolysis of ATP was necessary at both the outer and inner membranes. However, the protonophores carbonylcyanide m-chlorophenylhydrazone and nigericin, the K(+) ionophore valinomycin, and the F(1)F(0) ATPase inhibitor oligomycin had only marginal effects on uptake through the outer membrane but severely inhibited inner membrane translocation, indicating the unusual requirement of both the electrical and chemical components of the electromotive force generated across the inner membrane. The results are consistent with a mechanism involving stepwise transfer of tRNA through distinct outer and inner membrane channels.

The effects of nickel (II) ions and its complexes on the products arising from the γ-radiolysis of thymine were studied. The decomposition of the pyrimidine base and formation of different radiolytic products indicate that nickel(II) ions or its complexes have little effect on the radiosensitivity of thymine. The transient hydroxyl adduct of thymine reacts with Ni(II) with the formation of a complex having a nickel–carbon bond. The rate constants for the reactions are of the order of 106 dm3mol−1s−1. Possible mechanisms for the formation of different products in the radiolysis of thymine in the presence of nickel(II) compounds are discussed.

The effect of γ-radiation on the flavin moiety of dihydroorotate dehydrogenase was studied by fluorescence spectroscopy. Irradiation of aerated solutions (0-7 Gy) led to a small increase in fluorescence intensity, but with higher doses a decrease in intensity was observed. The increase in fluorescence intensity after irradiation at low doses may be attributed to protein unfolding, leading to greater exposure of flavin groups and a concomitant increase in separation between the flavin moiety and the iron - sulphur centre. This was confirmed by fluorescence quenching studies using potassium iodide as quencher. The Stern - Volmer constant calculated for iodide quenching indicates a two-fold increase in the fraction of flavin moiety being accessible to the quencher after 6·6 Gy. No spectral change was observed when unirradiated or irradiated enzyme was denatured with guanidine hydrochloride. However, a decrease in fluorescence intensity in the case of irradiated samples indicated a radiation-induced decrease in the flavin fluorophore. The flavin fluorophore loss in dihydroorotate dehydrogenase was also determined using aerated, argon-saturated or nitrous oxide-saturated solutions. H and OH radicals were found to have nearly equal contributions in damaging the flavin moiety of dihydroorotate dehydrogenase.

The effect of γ-radiation on tyrosine residues of dihydroorotate dehydrogenase under different conditions was investigated by means of fluorescence spectroscopy and second-derivative spectrophotometry. No change in the fluorescence spectral distribution was observed when unirradiated and irradiated enzyme were denatured in guanidine hydrochloride. However, decreases in fluorescence intensity in irradiated samples indicates a radiation-induced modification of tyrosine residues. The fluorescence intensity at 340 nm decreased exponentially with radiation dose in aerated medium but non-exponentially under argon and nitrous oxide-saturated conditions. The percentage loss of tyrosine fluorescence under different conditions was determined. The number of tyrosine residues left intact following irradiation at a dose for 50% inactivation under different conditions was measured by second-derivative absorption spectrophotometry. The results obtained from both these methods show that the hydroxyl radical is less efficient in inducing radiation damage of tyrosine in aerated conditions compared with that under deoxygenated conditions. This lower efficiency of the hydroxyl radical in aerated medium has been attributed to the protective effect of oxygen and/or the superoxide radical anion.

An investigation was carried out to determine if the diagnosis of gonorrhea in women by endocervical smear and culture differed in those taking oral contraceptives from those not taking the “pill.” One hundred and fifty female contacts of men with gonorrhea were investigated. One-half were “on the pill.” Urethral, endocervical and rectal specimens were examined by Gram’s stain and by culture on selective and nonselective media. No significant difference was observed in the number of patients suffering from gonorrhea at any site between those taking and those not taking the pill. Neither was any difference detected in infection of the cervix. Thus changes in the cervix during the course of oral contraception have no detectable influence on the diagnosis of gonorrhea.

Aqueous solutions of uracil (U) were irradiated with Co-60 γ-rays in the presence of electron scavengers, e.g. nitrous oxide and nitrate. Analysis of the products was carried out by means of paper chromatography. In N2O saturated solution, the degradation of uracil has been ascribed to the intermediate formation of a hydroxyl adduct which it has been argued leads to products through an electron transfer process, and G(-U) was found to be equivalent to 0.5R where R comprises H, eaq- and OH. The observed results have been compared with those reported earlier and the apparent anomalies have been rationalised in terms of a dose rate effect. NO3- ion has, however, been found to behave somewhat differently as an electron scavenger. The concentration of N03- was found to be a decisive factor in determining the course of radiolysis. Thus G(-U) is equivalent to ∼0.5 GR at low or zero nitrate concentration, ∼0.5 GOH over the range (0.5 - 3) × 10-3 M and ∼GOH at higher concentrations.

Aqueous solutions of uracil(U) in the presence of iron(III) were irradiated with 60Co γ-rays both in the presence and in the absence of dissolved oxygen. The products of radiolysis (uracil dimer, cis- and trans-uracil glycol, hydroxy-dihydrouracil and isobarbituric acid) were separated by means of paper chromatography using n-butanol: water (86 : 14) as the solvent. Radiolytic reduction of Fe(III) and the formation of Fe(II) were followed spectrophotometrically. In the absence of any additive, G(- U) is ∼ 1·3, but with Fe(III) added G(- U) approaches a limiting value of 3·3 and the yield of cis-glycol increases. Radiosensitization by Fe(III) is found to be different from that of oxygen, which results in the yield of cis glycol decreasing and the yields of trans glycol and isobarbituric acid increasing. The mechanisms involved are discussed.

Tissues from rabbit lung were found to incorporate radioactivity from [3H]mannose into the oligosaccharide of a polar lipid soluble in chloroform/methanol/water (10:10:3, by vol.). Only one oligosaccharide-lipid was formed and the composition of the radiolabelled carbohydrate moiety was Glc3Man9(GlcNAc)2. An antitumour antibiotic, bleomycin, and an anti-inflammatory steroid, methylprednisolone, partially inhibited the incorporation of [3H]mannose into oligosaccharide-lipids and in addition resulted in the production of two new components, Man5(GlcNAc)2 and Man2(GlcNAc)2. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of the glycoproteins synthesized from the oligosaccharide-lipid intermediates showed labelled components with Mr greater than 200000, 130000, 80000 and 62000. The addition of the drugs resulted in the same pattern with the addition of a new component of Mr 36000. Endoglucosaminidase H-treatment of the glycopeptides isolated from the Pronase-digested glycoproteins indicated that the oligosaccharide units in the glycoproteins were of the high-mannose-type.

Shelf-life of emulsions is very much linked with the stability of the emulsifier/s being used in their preparation. Instability of the emulsifiers may be caused due to some chemical changes taking place aiithin the emulsifiBr molecules such as oxidative, hydrolytic and/or others not well defined - resulting in their degradation. The present paper highlights the importance of the two aspects and some of the findings made in our laboratory on UJ/O emulsions where the aqueous phase contained high concentration of electrolytes.

Analogue calorimetry for blends of poly(vinyl ester)s and polyacrylates has been studied. Hydrogenated monomers were used as analogues of the corresponding polymers. It is found that isomeric esters differing only in the orientation of the COO group mix with only small heat change, which can be positive or negative. The values of the interaction energy density, B12 (in cal/cm³), are −0.045, 0.031, and −0.076, respectively, for the following binary mixtures; ethyl acetate + methyl propionate, n-propyl propionate + ethyl butyrate, and phenyl propionate + ethyl benzoate. The negative heat of mixing for the two pairs of very similar liquids, although unexpected, explains why the corresponding polymers are miscible. The small positive heat of mixing for the other pair is sufficient to predict demixing of the corresponding polymers, viz., poly(n-propyl acrylate) and poly(vinyl butyrate), which contradicts the observation of their homogeneous mixing. This suggests that hydrogenated monomers are not always the proper analogues for vinyl polymers for the prediction of the interaction energy. A novel flow calorimeter is also described. H^E and V^E data for binary mixtures of the above esters are presented.

Ultrastructural examination of rat tracheal explants at various times of culture in a serum-free and hormone-supplemented medium containing retinoic acid showed that the cytological characteristics of the epithelium were well preserved for at least 192 h. Hybridization analyses for mucin core protein mRNA in the explants were performed with a 30-base oligonucleotide probe, the design of which was based on the tandem repeat sequence of the rat intestine mucin core protein. The probe reacted with total RNA prepared from trachea, intestine and colon, but not with total RNA obtained from liver or alveolar region of the lung. Type-I keratin expression was observed in the explant grown at different periods of time in a medium with and without retinoic acid. The hybridization probe gave a prominent reaction with RNA preparations obtained from tracheal explants incubated for as long as 192 h in a medium containing retinoic acid. In the absence of retinoic acid, however, the mucin message was evident at the 24 h time point but thereafter decreased to barely detectable levels. When retinoic acid was added at 96 h to the latter cultures, the mucin mRNA was prominent again after additional incubation for 24 and 48 h. Northern-blot analyses of tracheal RNA showed a diffuse band at approx. 7.5 kb. Addition of a variety of chemical and pharmacological agents to explants cultured in the presence of retinoic acid had no dramatic induction or inhibitory effects on the mucin mRNA. Only the steroid prednisolone had a reproducible inhibitory effect.

Aqueous solutions of Co(III)-ethylenediamine tetraacetate (C) at different pH were irradiated with X-rays both in the presence and absence of dissolved oxygen. Radiolytic decomposition of the metal chelate and the formation of hydrogen peroxide and formaldehyde were determined. The radiolysis was found to be initiated by attack both at the ligand and at the central metal ion of the metal chelate by the free radicals derived from water. A detailed radio- lytic mechanism has been discussed. From competition kinetic studies with methanol in neutral medium the rate constant, k(OH + C) was found to be 5.3 × 108 M-1 sec-1.

A review of solvent extraction separation studies of niobium and tantalum, either individually or together from other associated elements, using various solvents, is presented.

A review on the studies of solvent extraction of zirconium and hafnium, either individually or together from other associated elements, using various solvents has been presented.In the Periodic Table, one can trace some element pairs, which have very closely similar chemical properties. Of these, zirconium and hafnium, due to lanthanide contraction form one such typical pairs, which generally occur together in nature and hence are termed congeneric. Segregation of these elements and separation of the individual metals from the complex matrix is of considerable importance in geochemistry and reactor technology.Of the various methods employed in separation chemistry, liquid-liquid extraction procedure is widely used for its high degree of selectivity under specific conditions. In order to develop a simple selective separation procedure of zirconium and hafnium it is necessary to study the extraction of the individual elements with different types of solvents.The following discussion has been classified with respect to the various classes of solvents used. At the end, a brief summary of the different systems together with the conditions chosen and literature citation s have been given in a tabular form.

The gas chromatographic method of characterization of polymer blends with regard to the state of binary polymer mixtures, origin of miscibility in miscible blends, evaluation of the noncombinatorial free energy parameters χ23' and χ23*' for miscible blends, and structural information of microphase-separated copolymer systems, etc. are reviewed with discussions of some selected polymer-polymer systems. A brief discussion of the principle and practice of GC with a polymer stationary phase, of the evaluation of χ and χ*, of sources of error and accuracy of the method, and of column support materials and support loading is also presented. Preliminary results of an inverse gas chromatography study of the newly reported miscible polymer pair poly(vinyl propionate) and poly(ethyl acrylate) are presented.

A soluble glycoprotein of Mr = 80,000 has been isolated from lung lavage of patients with alveolar proteinosis and found to contain 5 residues of hydroxyproline, 91 residues of glycine, 3 residues of methionine, 3.8 molecules of sialic acid, 6 molecules of mannose, 5.9 molecules of galactose, 1 molecule of fucose, and 9.1 molecules of glucosamine. Cyanogen bromide (CNBr) treatment of the glycoprotein resulted in four peptides with molecular weights of 36,000, 27,000, 12,000, and 5,000. The chemical compositions of the CNBr peptides indicated the presence of hydroxyproline and high amounts of glycine in all but one of the peptides; two of the four CNBr peptides contained carbohydrate. Limited trypsin digestion of the glycoprotein of Mr = 80,000 resulted in four peptides with molecular weights of 62,000, 36,000, 26,000 and 18,000, the latter being the NH2-terminal peptide of the native glycoprotein molecule. The peptide of Mr = 26,000 was found to be the COOH-terminal peptide.

An oestrogen-induced secretory protein from mouse uterine luminal fluid was purified by CM-Affi-Gel Blue chromatography and reverse-phase h.p.l.c. This protein has an apparent molecular mass of approx. 70 kDa both by SDS/polyacrylamide-gel electrophoresis (with or without 2-mercaptoethanol) and by gel-filtration column chromatography, indicating that it exists as a single-chain polypeptide. Further analysis of the protein revealed that it is highly basic (pI greater than or equal to 10) and is a glycoprotein. The N-terminus appears to be blocked to Edman degradation. The partial amino acid sequence of a fragment was obtained by cleavage with CNBr; no sequence homology was apparent between the analysed fragment and other known sequences. The incorporation of [35S]methionine into uterine proteins in vitro revealed that oestrogen treatment of immature mice stimulates both synthesis and secretion of the 70 kDa protein. An enzyme-linked immunosorbent assay with polyclonal antibody was used to determine the tissue distribution of the protein. Tissues such as lung, brain, spleen, muscle, intestine, liver, kidney and ovary of oestrogen-treated mice did not have detectable amounts of the 70 kDa protein. Immunoreactivity was present in uterine and vaginal tissues from oestrogen-treated animals. The 70 kDa protein was not induced by testosterone or progesterone. Although the function of this protein is unknown, it is useful as a marker for the study of oestrogen action in the mammalian uterus as well as regulation of gene expression at the molecular level.

The reactions of OH*and eaq−adducts of uracil and thymine with Cu(II) ions in aqueous solutions were followed by pulse radiolysis. The transient absorption spectra of the OH*adducts of uracil when followed in the presence of Cu(II) ions show growth in absorption at wavelengths 420 and 350 nm at 15 μs and 65 μs after the pulse respectively. Similar transient absorption spectra of thymine showed growth in absorption at wavelengths 390 and 320 nm at 38 μs and 65 μs after the pulse respectively. The rates of electron transfer from the OH*adducts of uracil and thymine to various Cu(II) compounds when monitored at 360 nm lie between 106and 108mol−1dm3s−1this implies that the electron transfer process is not an efficient process. Low rate constants coupled with the spectral changes suggest formation of a radical copper adduct which decays by water insertion to give cis-glycols as the major product. The electron transfer from the electron adducts of uracil and thymine to various copper(II) compounds takes place more efficiently (rate constants of the order of 108and 109mol−1dm3s−1) compared with that from the OH*adducts. The t-butanol radicals formed on scavenging the OH*radicals also produce adducts with Cu(I) ions which are formed on oxidation of the electron adducts by Cu(II) ions. This adduct has absorption around 400 nm both in the case of uracil and thymine.

Neutral aqueous solutions of 1:1 and 1:2 copper(II) iminodiacetates (CuII-IDA and CuII(IDA)2) were irradiated with 60Co-gamma rays both in the presence and in the absence of various scavengers. The reducing radicals, e.g., e-aq, H, CO-2 and CH2OH were found to reduce the metal ion in both 1:1 and 1:2 complexes producing corresponding Cu(I) species which were found to be easily oxidizable by oxygen. If oxygen is present in the system, the superoxy radicals are initially formed which have been found to attack the metal chelates to produce Cu(I) species which is, however, found to be remarkably stable. This extraordinary stability has been ascribed as due to formation of Cu(II)-superoxy complexes. The reaction of the hydroxyl radical with the complexes leads to the degradation of the ligand yielding glycine, formaldehyde and glyoxalic acid. It is argued that two types of carbonyl compounds could arise from two different modes ofOH attack; while the formation of CH2O was held due to OH attacking the metal centre, the formation of CHO.COOH was assumed to arise from the fraction of OH attacking the ligand. The rate constants for the reactions of OH with CuII-IDA and CuII(IDA)2, leading to the formation of formaldehyde were determined through competition kinetic studies as (9.5 ± 0.5) × 108 and (6.5 ± 0.5) × 108 M-1 s-1 respectively. The rate constant for the reaction of OH with CuII(IDA)2, where glyoxalic acid is formed was found to be (4.0 ± 0.2) × 108 M-1 s-1

A glycoprotein of Mr 62 000 was isolated from lung lavage material of patients with alveolar proteinosis. The glycoprotein was found to contain (per molecule) 72 residues of glycine, 5 residues of hydroxyproline, 3 molecules of sialic acid, 4.9 molecules of mannose, 4.0 molecules of galactose, 0.9 molecule of fucose and 7.0 molecules of N-acetylglucosamine. Limited pepsin digestion of the glycoprotein resulted in six peptides, three of which contained hydroxyproline and nearly 30% glycine, and two of which contained all the carbohydrate present in the glycoprotein of Mr 62 000. The three peptides containing hydroxyproline and with high content of glycine contained a repeating -Gly-X-Y-sequence in the peptide chain. Partial amino acid-sequence analyses on the peptides derived from the digestion of the alveolar glycoprotein with various proteolytic enzymes indicate that this glycoprotein is characterized by the presence of alternating collagenous and non-collagenous regions in the same polypeptide chain.

Difficulties in assessing the average fiber length in jute slivers are discussed. Some of the methods that are available for determining the average fiber length are examined and a simple and quick method is suggested. In the method proposed a beard is prepared by clamping the sliver at one point normal to its length and removing the loose fibers from both sides of the clamp. The weight profile of a beard prepared in this way is shown to be reasonably exponential, and hence a plot on semi-log scale will be a straight line. From the slope of the line the average fiber length can be calculated using the formula suggested. Instead of plotting the whole weight profile, the average fiber length can also be calculated from the weights of two 2-in. pieces of the beard cut at two points of the beard, and this cutting method gives values of avenge fiber length that are in good agreement with values obtained from the slope of the log-linear plot. The cutting method proposed is a quick one and appears to be reliable.

The reactions of SO4−•radicals with cytosine and its derivatives have been studied in dilute aqueous solutions. The results show that the nature of the group attached to N-1 of the base greatly influences the reaction sequences. Presence of copper(II) ions greatly affects the reaction pathways, where it is observed that the substrate consumption increases drastically indicating initiation of some chain reactions. Release of unaltered base from cytidine and deoxycytidine also increases under these conditions.

Aqueous solutions of Cu(II) Metronidazole (CuIIM) at neutral pH were irradiated with 60Co ?-rays under different conditions of radiolysis. The radiolytic formation of HNO2and CuIwas followed. The radiolytic yields of chromophore loss of CuIIM were also determined under different conditions. The OH radicals attack the metal complex to give the OH adducts of the ligand at C2, C4, and C5either directly or through the formation of Cu(III) species. The C5–OH adduct, however, undergoes oxidative denitration and as a result the metal complex is decomposed. The OH adducts also undergo electron transfer to CuIIion to give reduced complex. No denitration was observed due to the reaction of eeq-with the metal complex. On the other hand, the nitro group of the ligand in the complex undergoes successive 4-electron reduction to give hydroxylamino derivative. From the competition kinetics using t-butyl alcohol as the scavenger of OH in N2O saturated solution of the metal complex, the rate constant for the reaction of OH with complex was evaluated to be ca. 2.1×109dm3mol-1s-1which is of the same order as that observed in the case of free metronidazole.

Aqueous solutions of thymine (T) in the presence of Fe(III) were irradiated under deaerated conditions at pH ˜2. The products of radiolysis were separated by two dimensional thin-layer chromatography. In the absence of any metal ion, the G(-T) is 2.6 but when Fe(III) is present during radiolysis, the G(-T) increases significantly and reaches a limiting value of 3.2. The yields of the hydroxylated products of thymine also increase in the presence of Fe(III). The results were explained by a mechanism which involves the interactions of Fe(III) with the transient adducts of thymine.

Aqueous solutions of potassium periodate in neutral medium were irradiated with X-rays and with Gobalt-60 gamma rays. It was observed that the periodate on radiolysis is reduced only to iodate and no other reduction product was detected. A mechanism for the radiation induced reduction of periodate in aqueous solution is proposed and discussed. Effect of methanol on the course of radiolysis has also been studied.