bluuebunny/crossref_metadata_2025 huggingface dataset:
The nature and distribution of copper, lead, and zinc in soils of a highly urbanised sub-catchment (Iron Cove) of Port Jackson, Sydney
Authors: Snowdon R. , Birch G. F.
Published: May 2004

Iron Cove catchment (~1500 ha) on the southern shores of Port Jackson (Sydney) has been highly urbanised (>90%) for a considerable time (1800s). A map of the area was divided into squares 200 by 200 m and a soil sample was taken randomly in each defined area from the dominant land use type in each square (n = 374). The objectives of the study were to determine the distribution and sources of heavy metals (Cu, Pb, Zn) in surface soils over the catchment and to assess soil quality in terms of guidelines and bioavailability of these metals.The concentrations of Cu, Pb, and Zn were determined for total soil and on a normalised basis. These metals are elevated across the whole catchment, with mean total concentrations for Cu, Pb, and Zn of 62, 410, and 343 mg/kg and 50 percentiles of 44, 203, and 224 mg/kg, respectively, whereas mean enrichment over background is 2, 5.5, and 4.6 times, respectively. Such a wide, regional metal enrichment is probably related to atmospheric deposition from industry inside and beyond the catchment. The highest concentrations of most metals were in soils from the north-east part of the catchment in an area where dwellings and buildings are oldest and where major roads and railway lines converge. Normalise data suggest sources of these metals are roads, railway lines, and older lead-painted houses. Independent studies in the catchment support roads as being an important source of metals in the area. Total soil chemistry indicates that 34, 33, and 56% of the samples were above the Australian and New Zealand Environment and Conservation Council (ANZECC) and National Health and Medical Research Council (NH&MRC) guidelines for Cu, Pb, and Zn, respectively, and selective extraction procedures (EDTA and HCl) indicate that 46–86% of these metals may be bioavailable.
Effects of a water treatment residue, lime, gypsum, and polyacrylamide on the water retention and hydraulic conductivity of two contrasting soils under field conditions in KwaZulu-Natal, South Africa
Authors: Moodley M. , Johnston M. A. , Hughes J. C. , Titshall L. W.
Published: May 2004

Water treatment residue (WTR), a waste by-product of the 'drinking' water treatment industry, consists mainly of clay and fine silt flocculated out of suspension by chemicals such as polyelectrolytes and aluminium sulfate. This residue was disposed of almost exclusively in landfill, but land treatment is increasingly being seen as a possible alternative for this form of waste. A key concern, however, is that should the WTR decompose to its constituent fractions, this could cause blockage of pores and decrease the hydraulic properties of soil. To test this hypothesis, 2 field experiments were established on physically contrasting soils in KwaZulu-Natal, South Africa. Application rates from 0 to 1280 Mg/ha of WTR were compared with amendments of lime, gypsum, and polyacrylamide to determine their effects on water retention and hydraulic conductivity. Although after 3 years at one experiment and 2 years at the second differences between the WTR treatments were measurable, only the 1280�Mg/ha application rate was significantly different from the control. The chemical amendments that were applied purely as comparative treatments had no significant influence on either water retention or hydraulic conductivity. Neither soil showed any difference in readily available water content. The experiments showed that, in both soil types, the WTR increased water retention and hydraulic conductivity but that improvement in both of these properties was only significant at the 1280 Mg/ha application rate. Thus, very high amounts of WTR must be added to affect these physical properties of soils.
A field study of phosphorus mobilisation from commercial fertilisers
Authors: Nash D. , Hannah M. , Clemow L. , Halliwell D. , Webb B. , Chapman D.
Published: May 2004

Fertilisers contribute to phosphorus (P) exported from agricultural catchments in south-eastern Australia. Phosphorus concentrations were initially measured in overland flow caused by rainfall after broadcasting either single superphosphate [SSP, Ca(H2PO4)2] or diammonium phosphate [DAP, (NH4)2HPO4] blends to pastures. In addition, P concentrations in overland flow were measured at intervals down border irrigation bay before and after fertiliser application. The period between fertiliser application and irrigation varied from 1 to 10 days.For the rainfall-induced overland flow, total dissolved P (TDP) concentrations were higher where DAP rather than SSP had been applied. For the irrigation study, sampling position behind the wetting front, irrigation pre and post fertiliser application, and irrigation number post fertiliser application explained 49.7, 20.5, and 15.2% of the total sum of squares, respectively. TDP concentrations were highest in the wetting front and diminished with distance behind the wetting front. For the irrigation before, and 2 irrigations following, fertiliser application, concentrations in the wetting front were 2.3, 17.6, and 6.5 mg TDP/L, respectively. In general, wetting front concentrations were c. 4 times the mean concentrations for the bays. As most P is exported when the wetting front enters the drainage network, sampling behind the wetting front would appear to underestimate P exports. The TDP concentration decreased as the time between fertiliser application and irrigation increased but the effects were variable between farms and fertilisers. Contrary to the rainfall induced overland flow study, in the irrigation study higher TDP concentrations were measured where SSP rather than DAP had been applied. This finding is explained in terms of differing rates of P mobilisation from the 2 fertiliser blends and an interaction with soil hydrology. The rapidly infiltrating water at the wetting front of irrigation-induced overland flow is likely to carry with it P mobilised at, or near, the soil surface and P infiltration will be proportional to mobilisation rates. It is suggested that higher rates of P mobilisation from DAP than SSP would reduce P exports in border irrigation systems where DAP is applied to the soil.
Endometrial calbindins are critical for embryo implantation: Evidence fromin vivouse of morpholino antisense oligonucleotides
Authors: Luu Kien C. , Nie Gui Ying , Salamonsen Lois A.
Published: May 2004

The endometrium is receptive to embryo implantation only for a short period in each reproductive cycle: development of receptivity requires alterations in endometrial gene expression. Calbindin (CaBP)-d9k and CaBP-d28k are related proteins containing EF hand motifs that have a high affinity for Ca2+. We previously demonstrated that endometrial expression of CaBP-d9k mRNA is highly regulated during implantation in the mouse. This project aimed to determine the temporal and spatial expression of both CaBP proteins during early pregnancy and to establish whether they are necessary for blastocyst implantation. CaBP-d28k protein, like CaBP-d9k, was up-regulated in the endometrial epithelium just before implantation but disappeared at implantation sites after attachment. By the judicious intrauterine injection of morpholino oligonucleotides (MO) against CaBP-d9k into WT andCaBP-d28knull mice just before implantation, we selectively eliminated one or both CaBPs from the uterine epithelium. Implantation was blocked only when both CaBP-d9k and CaBP-d28k were absent: treated WT mice and untreatedCaBP-d28knull mice were fertile. Furthermore, the effect on implantation was highly dependent on the timing of injection of MO. This report examining the function of implantation-related genes in the uterus using MO demonstrates that this technique is a highly effective means to specifically target uterine proteinsin vivo. This study provides evidence for an absolute requirement for CaBPs during the early phase of embryo implantation, and thus that regulation of Ca2+availability in the uterine environment of the implanting embryo is critical for successful implantation.
An expanded genetic code with a functional quadruplet codon
Authors: Anderson J. Christopher , Wu Ning , Santoro Stephen W. , Lakshman Vishva , King David S. , Schultz Peter G.
Published: May 2004

With few exceptions the genetic codes of all known organisms encode the same 20 amino acids, yet all that is required to add a new building block are a unique tRNA/aminoacyl-tRNA synthetase pair, a source of the amino acid, and a unique codon that specifies the amino acid. For example, the amber nonsense codon, TAG, together with orthogonal
Methanococcus jannaschii
or
Escherichia coli
tRNA/synthetase pairs have been used to genetically encode a variety of unnatural amino acids in
E. coli
and yeast, respectively. However, the availability of noncoding triplet codons ultimately limits the number of amino acids encoded by any organism. Here, we report the design and generation of an orthogonal synthetase/tRNA pair derived from archaeal tRNA
Lys
sequences that efficiently and selectively incorporates an unnatural amino acid into proteins in response to the quadruplet codon, AGGA. Frameshift suppression with
l
-homoglutamine (hGln) does not significantly affect protein yields or cell growth rates and is mutually orthogonal with amber suppression, permitting the simultaneous incorporation of two unnatural amino acids, hGln and
O
-methyl-
l
-tyrosine, at distinct positions within myoglobin. This work suggests that neither the number of available triplet codons nor the translational machinery itself represents a significant barrier to further expansion of the genetic code.
Mechanical tweezer action by self-tightening knots in surfactant nanotubes
Authors: Lobovkina Tatsiana , Dommersnes Paul , Joanny Jean-Francois , Bassereau Patricia , Karlsson Mattias , Orwar Owe
Published: May 2004

Entanglements and trefoil knots on surfactant nanotubes in the liquid phase were produced by a combination of network self-organization and micromanipulation. The resulting knots are self-tightening, and the tightening is driven by minimization of surface free energy of the surfactant membrane material. The formation of the knot and the steady-state knot at quasi-equilibrium can be directly followed and localized by using fluorescence microscopy. Knots on nanotubes can be used as nanoscale mechanical tweezers for trapping and manipulation of single nano- and micrometer-sized high-aspect ratio objects. Furthermore, we demonstrate that by controlling the surface tension, objects captured by a knot can be transported along given trajectories defined by the nanotube axes.
Natural killer cells distinguish innocuous and destructive forms of pancreatic islet autoimmunity
Authors: Poirot Laurent , Benoist Christophe , Mathis Diane
Published: May 2004

In both human patients and murine models, the progression from insulitis to diabetes is neither immediate nor inevitable, as illustrated by the innocuous versus destructive infiltrates of BDC2.5 transgenic mice on the nonobese diabetic (NOD) versus C57BL/6.H-2g7genetic backgrounds. Natural killer (NK)-cell-specific transcripts and the proportion of NK cells were increased in leukocytes from the aggressive BDC2.5/B6.H-2g7lesions. NK cell participation was also enhanced in the aggressive lesions provoked by CTLA-4 blockade in BDC2.5/NOD mice. In this context, depletion of NK cells significantly inhibited diabetes development. NOD and B6.H-2g7mice exhibit extensive variation in NK receptor expression, reminiscent of analogous human molecules. NK cells can be important players in type 1 diabetes, a role that was previously underappreciated.
Microtesla MRI with a superconducting quantum interference device
Authors: McDermott Robert , Lee SeungKyun , Haken Bennie ten , Trabesinger Andreas H. , Pines Alexander , Clarke John
Published: May 2004

MRI scanners enable fast, noninvasive, and high-resolution imaging of organs and soft tissue. The images are reconstructed from NMR signals generated by nuclear spins that precess in a static magnetic fieldB0in the presence of magnetic field gradients. Most clinical MRI scanners operate at a magnetic fieldB0= 1.5 T, corresponding to a proton resonance frequency of 64 MHz. Because these systems rely on large superconducting magnets, they are costly and demanding of infrastructure. On the other hand, low-field imagers have the potential to be less expensive, less confining, and more mobile. The major obstacle is the intrinsically low sensitivity of the low-field NMR experiment. Here, we show that prepolarization of the nuclear spins and detection with a superconducting quantum interference device (SQUID) yield a signal that is independent ofB0, allowing acquisition of high-resolution MRIs in microtesla fields. Reduction of the strength of the measurement field eliminates inhomogeneous broadening of the NMR lines, resulting in enhanced signal-to-noise ratio and spatial resolution for a fixed strength of the magnetic field gradients used to encode the image. We present high-resolution images of phantoms and other samples andT1-weighted contrast images acquired in highly inhomogeneous magnetic fields of 132 μT; here,T1is the spin-lattice relaxation time. These techniques could readily be adapted to existing multichannel SQUID systems used for magnetic source imaging of brain signals. Further potential applications include low-cost systems for tumor screening and imaging peripheral regions of the body.
Effects of intraruminal propionate supplementation on nitrogen utilisation by the portal-drained viscera, the liver and the hindlimb in lambs fed frozen rye grass
Authors: Savary-Auzeloux Isabelle C. , Majdoub Linda , LeFloc'h Nathalie , Ortigues-Marty Isabelle
Published: May 2004

The influence of propionate supplementation on the splanchnic metabolism of amino acids (AA) and other N compounds (urea-N and NH3-N) and the supply of AA and NH3-N to the hindlimb was investigated in growing lambs. Six rumen-cannulated and multicatheterised lambs (32·2kg) were fed frozen rye grass at 690kJ metabolisable energy intake/d per kg average metabolic body weight. They were infused intraruminally with a salt solution (control) or with propionate solutions at 0·23mol/l (P1) or 0·41mol/l (P2) infused at a maximal rate of 1·68 (sd 0·057) ml/min according to a repeated Latin square design. The propionate infusion did not increase the net portal appearance of total AA (TAA)-N but increased that of some branched-chain AA (valine and to a lesser extent isoleucine). Simultaneously, the propionate treatment (especially P2) induced an increased TAA utilisation by the liver. This was due mainly to an increased (+79%;P<0·07) utilisation of the essential AA and particularly the branched-chain AA. A stimulation of protein synthesis in the liver is hypothesised since (1) propionate stimulated insulin secretion and (2) utilisation of non-essential AA were less influenced by the propionate treatment in the liver (except for alanine), suggesting that the AA utilised by the liver were directed towards protein synthesis rather than towards oxidation or urea synthesis. At the splanchnic level, the propionate treatment did not have any effect on the TAA, non-essential AA and essential AA, except for a net splanchnic release that was decreased for leucine (P<0·02) and methionine (P<0·01) and increased for threonine (P<0·05). The propionate treatment did not have any effect on the hindlimb uptake of AA (essential and non-essential). As a consequence, even though the propionate treatment induced some major alterations in the splanchnic metabolism of AA, there were no changes in the net AA balance in the hindlimb (and hence probably on muscle growth). The role of the splanchnic tissues in the regulation of the AA supply to the peripheral tissues (such as muscle) therefore appears to be prominent in the regulation of muscle growth. Whether the peripheral tissues regulate their own supply by interacting with the splanchnic tissues (and especially the liver) or the liver is the only regulator of the AA supply to the muscle remains in doubt.
Use of Tween 40 and Tween 80 to deliver a mixture of phytochemicals to human colonic adenocarcinoma cell (CaCo-2) monolayers
Authors: O'Sullivan Sinead M. , Woods Julie A. , O'Brien Nora M.
Published: May 2004

Epidemiological evidence suggests that dietary intake of carotenoids and tocopherols may influence the risk of certain chronic diseases, such as cancer and CVD.In vitrostudies investigating the synergistic effects of mixtures of carotenoids and tocopherols have been hindered due to the difficulty of solubilising these lipophilic compounds. The objective of the present study was to develop a system for delivering tocopherols and carotenoids simultaneously to cells in culture. Differentiated human colonic adenocarcinoma cells (CaCo-2) were incubated with a mixture of these phytochemicals for 24 h. The phytochemical mixture included carotenoids (astaxanthin, canthaxanthin, lutein, lycopene, α-carotene, β-carotene) and tocopherols (α-tocopherol and γ-tocopherol). The emulsifiers polyoxyethylene sorbitan monopalmitate (Tween 40) and polyoxyethylene sorbitan monooleate (Tween 80) were employed as the delivery vehicles, and were compared with tetrahydrofuran (THF). Each vehicle was added at a maximum concentration of 1 ml/l. No toxic effects to the CaCo-2 cells were noted when Tween 40 or Tween 80 were used. Both Tween 40 and Tween 80 resulted in greater solubility of the mixture and delivered substantially more carotenoids and tocopherols to the cells than THF. In particular, lycopene was detected within the cells when Tween 40 and Tween 80 were employed, whereas it was below the limits of detection by HPLC when THF was used as the delivery vehicle. The phytochemicals were retained within the cells for 24 h after supplementation. Tween 40 and Tween 80 have potential as simple, rapid and non-toxic methods for delivering mixtures of carotenoids and tocopherols to cells in culture.
Fatty acid-mediated inhibition of IL-12 production by murine macrophages is independent of PPARγ
Authors: Zhang Meijuan , Fritsche Kevin L.
Published: May 2004

Our laboratory has reported thatn-3 PUFA can reduce host resistance toListeriainfection, in part, by impairingin vivoIL-12 biosynthesis. Recently, PUFA were shown to be ligands for PPAR, a novel family of nuclear receptors with three isoforms: PPARα, PPARδ/β and PPARγ. PPARγ is expressed in immune cells, such as T cells and macrophages. Two PPARγ agonists, 15-deoxy-Δ12,14-prostaglandin (PG) J2and rosiglitazone, have been shown to have immunomodulatory activityin vitro, including inhibiting IL-12 biosynthesis. We hypothesized thatn-3 PUFA inhibit IL-12 production through activating PPARγ. We used thioglycolate-elicited mouse peritoneal macrophages to study the effect of various fatty acids and their oxidized metabolites onin vitroIL-12 production. Our present results demonstrate that bothn-3 andn-6 PUFA can reducein vitroIL-12 biosynthesis, though less potently than 15-deoxy-PGJ2and rosiglitazone. GW9662, a PPARγ antagonist, reversed the inhibitory effect of rosiglitazone, but not that of PUFA. Our present findings suggest that fatty acid-mediated inhibition of IL-12 production is independent of PPARγ.
Assessing the impact of nutrition education on growth indices of Iranian nomadic children: an application of a modified beliefs, attitudes, subjective-norms and enabling-factors model
Authors: Salehi Mousa , Kimiagar S. M. , Shahbazi M. , Mehrabi Y. , Kolahi A. A.
Published: May 2004

In order to teach suitable feeding and hygiene practices to a group of randomly selected Qashqa'i tribe families with 406 children aged 0–59 months, a culturally appropriate community-based education intervention approach was used. To assess the impact of the intervention on the study group, another group of families with 405 children were randomly selected to serve as the controls. At the beginning of the intervention programme both groups of children had access to a similar diet, consisting of cereals, beans, oil, sugar, milk and yoghurt. Baseline data, age, gender, weight, height and mean arm circumference (MAC), were obtained before the intervention. Using Hubley's behavioural change model, the components of which deal with beliefs, attitudes, subjective norms and enabling factors, the research team studied the behaviour of the family members and tried to change their nutritional behaviour. This was achieved by designing a suitable education programme to be carried out for 12 months. During the programme, families were instructed to follow different methods of food preparation and cooking practices. The final data were collected 3 months after the end of the intervention programme. The results indicated that the children in the study group gained: 1·16 (SD 1·2) kg body weight, 0·033 (SD 0·05) m in height, 0·0067 (SD 0·015) m in MAC, 0·8 (SD 1) in weight-for-age Z-score, 0·97 (SD 1·7) in height-for-age Z-score and 0·28 (SD 1·8) in weight-for-height Z-score by the end of the study. The corresponding values for the control group were 0·42 (SD 1·0), 0·0167 (SD 0·047), 0·0017 (SD 0·012), 0·35 (SD 1·1), 0·56 (SD 1·5) and 0·014 (SD 1·6) respectively and the differences were statistically significant (P<0·05). These findings suggest that educational interventions involving parents and/or other family members who might play a role in the care behaviour and care resources are important in feeding the children energy- and protein-enriched, hygienic, simple and cheap foods. Such practices could improve child growth even under conditions of poverty.
Relative stability of transgene DNA fragments from GM rapeseed in mixed ruminal cultures
Authors: Sharma Ranjana , Alexander Trevor W. , John S. Jacob , Forster Robert J. , McAllister Tim A.
Published: May 2004

The use of transgenic crops as feeds for ruminant animals has prompted study of the possible uptake of transgene fragments by ruminal micro-organisms and/or intestinal absorption of fragments surviving passage through the rumen. The persistence in buffered ruminal contents of seven different recombinant DNA fragments from GM rapeseed expressing the5-enolpyruvylshikimate-3-phosphate synthase(EPSPS) transgene was tracked using PCR. Parental and transgenic (i.e. glyphosphate-tolerant; Roundup Ready®, Monsanto Company, St Louis, MO, USA) rapeseed were incubated for 0, 2, 4, 8, 12, 24 and 48 h as whole seeds, cracked seeds, rapeseed meal, and as pelleted, barley-based diets containing 65 g rapeseed meal/kg. The seven transgene fragments ranged from 179 to 527 bp and spanned the entire 1363 bp EPSPS transgene. A 180 bpribulose-1,5-bisphosphate carboxylase/oxygenase(Rubisco) small subunit fragment and a 466 bp 16S rDNA fragment were used as controls for endogenous rapeseed DNA and bacterial DNA respectively. The limit of detection of the PCR assay, established using negative controls spiked with known quantities of DNA, was 12·5 pg. Production of gas and NH3was monitored throughout the incubation and confirmed activein vitrofermentation. Bacterial DNA was detected in all sample types at all time points. Persistence patterns of endogenous (Rubisco) and recombinant (EPSPS) rapeseed DNA were inversely related to substrate digestibility (amplifiable for 48, 8 and 4 h in whole or cracked seeds, meal and diets respectively), but did not differ between parental and GM rapeseed, nor among fragments. Detection of fragments was representative of persistence of the whole transgene. NoEPSPSfragments were amplifiable in microbial DNA, suggesting that transformation had not occurred during the 48 h incubation. Uptake of transgenic DNA fragments by ruminal bacteria is probably precluded or time-limited by rapid degradation of plant DNA upon plant cell lysis.
Effects of ileo-rectal anastomosis on cholesterol metabolism in pigs fed either casein or extruded soya beans
Authors: Bento Ofélia P. , Martins José M. , Lança Maria J. , de Abreu Manuel C. , Viegas-Crespo Ana M. , Freire João P. B. , Almeida José A. A. , Riottot Michel
Published: May 2004

The importance of legume proteins in cholesterol metabolism has been recognised, but the hindgut contribution is still unclear. The present work was undertaken to address the role of the caecum–colon in cholesterol metabolism in intact (I) and ileo-rectal anastomosed (IRA) pigs fed with casein or extruded soyabean (ES) diets. Four groups of six growing pigs were assigned to the treatments (casein–I, casein–IRA, ES–I, ES–IRA) for 3 weeks. Plasma total cholesterol, LDL- and HDL-cholesterol were not modified by surgery or diet. In the liver, the ES diet significantly depressed non-esterified, esterified and total cholesterol. The treatments did not affect hepatic 3-hydroxy-3-methylglutaryl CoA reductase, cholesterol 7α-hydroxylase or sterol 27-hydroxylase activities. In the gallbladder bile of ES-fed pigs, total cholesterol was depressed while total bile acid concentration was increased. IRA and the ES diet markedly decreased the biliary bile acid microbial metabolites (namely hyodeoxycholic acid) and increased the primary bile acids (mainly hyocholic acid). The concentration of bile hydrophobic acids was decreased only by the ES diet. Faecal neutral sterol output was increased in ES-fed pigs, but the bile acid and the sum of neutral and acidic steroid outputs were not. Microbial transformation of neutral and acidic steroids was markedly reduced by IRA, especially in the ES-fed pigs. Thus, surgery and ES modulated the steroid profile but the caecum–colon did not seem to play a crucial role in determining cholesterolaemia in pigs.
Stable isotope-labelled vitamin C as a probe for vitamin C absorption by human subjects
Authors: Bates Christopher J. , Jones Kerry S. , Bluck Leslie J. C.
Published: May 2004

Factors affecting absorption of physiological doses of vitamin C in man have not been widely studied, partly because few suitable tools exist to distinguish recently absorbed vitamin C from endogenous vitamin. Stable isotope-labelled vitamin C provides such a tool. Fifteen healthy non-smoking subjects aged 26–59 years were studied. Each received 30 mg L-[1-13C]ascorbic acid orally on two occasions, 3–4 weeks apart. The ascorbate was given alone or with Fe (100 mg as ferrous fumarate) or with red grape juice, which is rich in polyphenols. Blood was collected at frequent intervals for 1 h, and then each hour for a further 3 h. Total concentration of vitamin C was measured fluorometrically and its13C-isotope enrichment was measured by GC–MS after conversion to volatile trimethylsilyl esters. Peak plasma enrichment occurred within 25–50 min. No kinetic variables were significantly altered by the iron fumarate supplement. Grape juice attenuated vitamin C absorption, reaching significance at the 20 min time point. There were weak correlations between isotope enrichment and body weight or endogenous ascorbate concentration. The increment in total plasma ascorbate was smaller if calculated from isotope enrichment than from vitamin C concentration increase. The dilution pool was much larger than the plasma ascorbate pool. Further studies are needed to resolve these paradoxes. Stable isotope-labelled ascorbate is potentially useful for measurement of vitamin C absorption by human subjects.
Comparison of plasma responses in human subjects after the ingestion of 3R,3R′-zeaxanthin dipalmitate from wolfberry (Lycium barbarum) and non-esterified 3R,3R′-zeaxanthin using chiral high-performance liquid chromatography
Authors: Breithaupt Dietmar E. , Weller Philipp , Wolters Maike , Hahn Andreas
Published: May 2004

Age-related macular degeneration (AMD) is one of the most common eye diseases of elderly individuals. It has been suggested that lutein and zeaxanthin may reduce the risk for AMD. Information concerning the absorption of non-esterified or esterified zeaxanthin is rather scarce. Furthermore, the formation pathway ofmeso(3R,3′S)-zeaxanthin, which does not occur in plants but is found in the macula, has not yet been identified. Thus, the present study was designed to assess the concentration of 3R,3R′-zeaxanthin reached in plasma after the consumption of a single dose of native 3R,3′R-zeaxanthin palmitate from wolfberry (Lycium barbarum) or non-esterified 3R,3′R-zeaxanthin in equal amounts. In a randomised, single-blind cross-over study, twelve volunteers were administered non-esterified or esterified 3R,3′R-zeaxanthin (5 mg) suspended in yoghurt together with a balanced breakfast. Between the two intervention days, a 3-week depletion period was inserted. After fasting overnight, blood was collected before the dose (0 h), and at 3, 6, 9, 12, and 24 h after the dose. The concentration of non-esterified 3R,3′R-zeaxanthin was determined by chiral HPLC. For the first time, chiral liquid chromatography–atmospheric pressure chemical ionisation-MS was used to confirm the appearance of 3R,3′R-zeaxanthin in pooled plasma samples. Independent of the consumed diet, plasma 3R,3′R-zeaxanthin concentrations increased significantly (P=0·05) and peaked after 9–24 h. Although the concentration curves were not distinguishable, the respective areas under the curve were distinguishable according to a two-sidedFandttest (P=0·05). Thus, the study indicates an enhanced bioavailability of 3R,3′R-zeaxanthin dipalmitate compared with the non-esterified form. The formation ofmeso-zeaxanthin was not observed during the time period studied.
Docosahexaenoic acid-enriched egg consumption induces accretion of arachidonic acid in erythrocytes of elderly patients
Authors: Payet Marianne , Esmail Mohamed H. , Polichetti Elisabeth , Le Brun Gaël , Adjemout Lounès , Donnarel Gérard , Portugal Henri , Pieroni Gérard
Published: May 2004

Many studies in humans volunteers have shown that dietary docosahexaenoic acid (DHA) supplied as triacylglycerol can increase DHA levels in blood lipids but often strongly decreases those of arachidonic acid (AA). The aim of the present study was to determine the effect of dietary supplementation with egg-yolk powder enriched in DHA, corresponding to the French recommended dietary allowance for DHA, on the blood lipid status of an elderly population. Institutionalised elderly individuals aged between 63 and 93 years consumed an egg product enriched in DHA (150 mg/d) once daily for 9 months. Plasma lipids and the fatty acid composition of erythrocyte membranes were determined every 3 months. The supplementation induced an increase in the PUFA content of plasma and erythrocyte membranes which was +14·5 and +25·3 %, respectively, at 9 months. This effect was mainly due to the level of DHA and, unexpectedly, to that of AA which continuously increased. This increase in AA was the result of an increased dietary intake (+50 mg/d) and very probably of an increased biosynthesis as demonstrated by the behaviour of di-homo-γ-linolenic acid. The supplementation resulted in a blood PUFA status comparable with that of young healthy controls. The data are consistent with a strong regulatory action of the dietary treatment on the subjects' lipid metabolism.
PARTICLE INTERACTION IN SOLUTIONS DERIVED FROM OX VITREOUS HUMOR
Authors: Woodin A. M. , Boruchoff S. A.
Published: May 2004

Solutions made by homogenization of vitreous humor exhibit anomalous viscosity at low shear rates due to interaction between hyaluronic acid and a hydroxyproline-containing material similar to collagen. The latter can be removed by filtration or centrifugation to give a solution whose viscosity is due to hyaluronic acid. On concentration the viscosity of the latter remains independent of shear rate and it is concluded that hyaluronic acid in the vitreous humor is not greatly asymmetric. There is no evidence that the soluble protein of vitreous humor contributes to the viscosity. Hyaluronic acid in vitreous humor is not in chemical combination with protein. The interaction between the hyaluronic acid and the collagen-like material is ascribed to weak, coulombic forces.
THE DEMONSTRATION OF A BLOOD-OCULAR BARRIER IN THE ALBINO RAT BY MEANS OF THE INTRAVITAM DEPOSITION OF SILVER
Authors: Wislocki George B. , Ladman Aaron J.
Published: May 2004

When silver nitrate is administered to rats in their drinking water for many months, they develop a generalized argyria. In the central nervous system, the deposition of silver follows the pattern of the so called hematoencephalic barrier (Wislocki and Leduc, (2); Dempsey and Wislocki, (3)). The present observations concern the deposition of silver in the rat's eye, investigated by both light microscopy and the electron microscope. In the eye, silver is not detected in the specific neural elements of the retina. Instead, it is heavily deposited in the basement membrane of the epithelium of the ciliary processes and in Bruch's basal membrane between the choriocapillary layer and the retinal epithelium. Traces of silver are visible in the basement membranes of the retinal capillaries with the electron microscope, but cannot be identified with the light microscope. In all of these respects, the pattern of the silver resembles the mode of its deposition in the brain. The heavy accumulation of metal in Bruch's membrane and the ciliary processes is analogous to that observed in the chorioid plexuses, and the traces encountered in the walls of the retinal capillaries correspond to traces observed in the basement membranes of the cerebral capillaries. Hence, with respect to silver, the eye possesses a blood-ocular barrier similar to the hematoencephalic barrier. Silver appears to be restrained from entering the aqueous humor by a barrier in the basement membrane of the ciliary processes, from reaching the photoreceptor elements of the retina by Bruch's basal membrane, and from penetrating the inner layers of the retina by a barrier in the basement membrane surrounding the retinal capillaries.
ON THE CHEMICAL COMPOSITION OF THE AXOPLASM OF SQUID GIANT NERVE FIBERS WITH PARTICULAR REFERENCE TO ITS ION PATTERN
Authors: Koechlin Bernard A.
Published: May 2004

Investigations dealing with the determination of the major chemical constituents of the axoplasm of the giant nerve fiber of the squid are described. Particular emphasis has been placed on determining the components involved in acid-base balance.

It was found that 72 per cent of the total solids of axoplasm, representing 13.5 per cent of the wet material, are of relatively low molecular weight (dialyzable) and consist mainly of charged ionic or dipolar constituents.

Of the 520 micromoles per gm. of total base, 72 per cent are balanced by organic acids: aspartic acid (65 micro equivalents per gm.), glutamic acid (10 micro equivalents), fumaric and succinic acids (15 micro equivalents), a new polycarboxylic acid (35 micro equivalents), and isethionic acid, a biologically novel sulfonic acid (220 micro equivalents).

Besides potassium, sodium, small amounts of calcium, and magnesium there is a considerable fraction of organic (nitrogenous) base.

Other features of the chemical composition of squid axoplasm include a relatively high concentration of taurine (100 micro equivalents) and an ultraviolet absorbing substance possibly identical with N-methylpicolinic acid. The distribution of the phosphates, especially the concentration of ATP, has been investigated.

Specific techniques elaborated in connection with this study have been described and the biochemical implications of the analytical results are discussed.
THE FINE STRUCTURE OF THE RENAL GLOMERULUS OF THE MOUSE
Authors: Yamada Eichi
Published: May 2004

Sections of mouse renal glomerulus fixed by perfusion with buffered osmium tetroxide solution have been studied with the electron microscope.

Four components are recognized in the mouse glomerulus: epithelium, basement membrane, endothelium, and intercapillary cell. The three cellular components all display in their cytoplasm mitochondria, Golgi bodies, endoplasmic reticulum, and uncharacterized vesicles.

The concepts of Hall, of Pease, and of Rhodin regarding the glomerular filtration surface are confirmed.

The epithelial cells are characterized by intricate, branching, interdigitating ridge-like processes or pedicels, the summits of which press against the urinary surface of the basement membrane, covering the glomerular capillary tuft almost completely except for narrow spaces about 200 to 300 A wide between the processes. These spaces are termed the epithelial filtration slits, and are bridged by a very delicate gossamer-like membrane about 30 A thick,—the filtration slit membrane.

The basement membrane is interposed everywhere between epithelial processes and endothelium, and between epithelial and intercapillary cells. The basement membrane of the filtration surface of the glomerular capillary has smooth surfaces and is about 800 A thick. It consists of three layers—a thick central lamina densa, appearing to have a very delicate felt-like structure, flanked on each side by thinner lamina rara externa and lamina rara interna. This membrane continues to the intercapillary space and makes a complicated sponge-work of varying thickness in which the intercapillary cells are enmeshed.

The endothelial cells are of moderate thickness in the nuclear region, but send out thin sheet-like extensions over the filtration surface. These extensions are about 300 to 400 A thick and are characterized by numerous round endothelial filtration pores about 500 to 1000 A in diameter.

The intercapillary tissue or mesangium is composed of the network of the basement membrane and the intercapillary cells.

The intercapillary cells, with characteristic fine fibrillar cytoplasm, make contact with epithelial and endothelial cells and are enmeshed within the network of the basement membrane. Rounded processes of intercapillary cells penetrate into the endothelial cell through the basement membrane, and may even perforate entirely through the endothelium. Such processes are called (after Zimmermann) the intracapillary colliculi.

In the endothelial cytoplasm close to the intracapillary colliculi are many dense endothelial juxtacollicular vesicles and caveolae.

The cell boundaries of the endothelial cell resemble terminal bars.

Some physiological speculations relating to glomerular structure are advanced.

The description of Zimmermann (54), based on a light microscope study, is confirmed in many respects.
STUDIES ON THE ENDOPLASMIC RETICULUM
Authors: Palade George E.
Published: May 2004

A survey of a large number of different cell types has indicated the presence of a network of membrane-bound cavities (the endoplasmic reticulum) in the cytoplasm of all cell types examined, with the exception of the mature erythrocyte.

In its simplest form, encountered in seminal epithelia and in leucocytes, the reticulum consists mainly of interconnected strings of vesicles and appears to be randomly disposed in three dimensions.

Local differentiations occur within the endoplasmic reticulum of all the cell types studied.

The membrane limiting the cavities of the endoplasmic reticulum appears to be continuous with the cell membrane and the nuclear membranes.
Localization of the nucleolar protein NO38 in amphibian oocytes.
Authors: Peculis B A , Gall J G
Published: May 2004

To examine the role of primary amino acid sequence in the localization of proteins within the nucleus, we studied the nucleolar protein NO38 of amphibian oocytes. We synthesized NO38 transcripts in vitro, injected them into the oocyte cytoplasm, and followed the distribution of the translation products. The injected RNA contained a short sequence encoding an epitope derived from the human c-myc protein. We used an mAb against this epitope to detect translation products from injected RNAs by Western blots and by immunofluoresent staining of cytological preparations. When full-length transcripts of NO38 were injected into oocytes, the translation products accumulated efficiently in the germinal vesicle, and a major fraction was localized in the multiple nucleoli. To identify protein domains involved in this nucleolus-specific accumulation, we prepared a series of carboxy-terminal deletions of the cDNA. Oocytes injected with RNA encoding truncated forms of NO38 were examined for altered patterns of protein accumulation. We defined a domain of about 24 amino acids near the carboxy terminus that was essential for nucleolar localization of NO38. This domain is separated by more than 70 amino acids from two putative nuclear localization signals near the middle of the molecule. Hybrid constructs were made which encoded part of Escherichia coli beta-galactosidase or pyruvate kinase fused to a long segment of NO38 containing the essential domain. Injection of RNA from these constructs showed that the essential domain was not sufficient to target the hybrid proteins to the nucleolus. We suggest that nucleolar accumulation of NO38 requires more than a single linear domain.
Mitosis and inhibition of intracellular transport stimulate palmitoylation of a 62-kD protein.
Authors: Mundy D I , Warren G
Published: May 2004

Recent studies suggest that a cycle of acylation/deacylation is involved in the vesicular transport of proteins between intracellular compartments at both the budding and the fusion stage (Glick, B. S., and J. E. Rothman. 1987. Nature (Lond.). 326:309-312). Since a number of cellular processes requiring vesicular transport are inhibited during mitosis, we examined the fatty acylation of proteins in interphase and mitotic cells. We have identified a major palmitoylated protein with an apparent molecular weight of 62,000 (p62), whose level of acylation increases 5-10-fold during mitosis. Acylation was reversible and p62 was no longer palmitoylated in cells that have exited mitosis and entered G1. p62 is tightly bound to the cytoplasmic side of membranes, since it was sensitive to digestion with proteases in the absence of detergent and was not removed by treatment with 1 M KCl. p62 is removed from membranes by nonionic detergents or concentrations of urea greater than 4 M. The localization of p62 by subcellular fractionation is consistent with it being in the cis-Golgi or the cis-Golgi network. A palmitoylated protein of the same molecular weight was also observed in interphase cells treated with inhibitors of intracellular transport, such as brefeldin A, monensin, carbonylcyanide m-chlorophenylhydrazone, or aluminum fluoride. The protein palmitoylated in the presence of brefeldin A was shown to be the same as that palmitoylated during mitosis using partial proteolysis. Digestion with two enzymes, alkaline protease and endoprotease lys-C, generated the same 3H-palmitate-labeled peptide fragments from p62 from mitotic or brefeldin A-treated cells. We suggest that the acylation and deacylation of p62 may be important in vesicular transport and that this process may be regulated during mitosis.
A synthetic peptide representing the consensus sequence motif at the carboxy-terminal end of the rod domain inhibits intermediate filament assembly and disassembles preformed filaments.
Authors: Hatzfeld M , Weber K
Published: May 2004

All intermediate filament (IF) proteins share a highly conserved sequence motif at the COOH-terminal end of their rod domains. We have studied the influence of a 20-residue peptide, representing the consensus motif on filament formation and stability. Addition of the peptide at a 10-20-fold molar excess over keratins K8 plus K18 had a severe effect on subsequent IF assembly. Filaments displayed a rough surface and variable diameters with a substantial amount present in unravelled form. At higher peptide concentration (50-100-fold molar excess), IF formation was completely inhibited and instead only loose aggregates of "globular" particles were formed. The peptide also influenced performed keratin IF in a dose-dependent manner. While a three-fold molar excess was sufficient to cause partial fragmentation of IF, a 50-fold molar excess caused complete disassembly within 5 min. Loosely associated protofibrils, short needlelike IF fragments, and aggregates of globular particles were detected. The motif peptide also caused the disassembly of filaments formed by desmin, a type III IF protein. Peptide concentrations and incubation times required for complete disassembly were somewhat higher than for the filaments containing K8 plus K18. A 50-fold molar excess was sufficient to cause complete disassembly within 1 h. Peptides unrelated in sequence to the motif did not interfere with filament formation or stability even when present for more than 12 h at a 100-fold molar excess. The results suggest that the motif sequence normally binds to a specific acceptor site for which the motif peptide can successfully compete. Taken together with current models of IF structure the results indicate that normal binding of the motif sequence to its acceptor must play an essential role in IF formation, possibly by directing the proper alignment of neighboring tetramers or protofilaments. Finally we show that in vitro formed IF are much more sensitive and dynamic strutures than previously thought.
In vitro analysis of the origin and maintenance of O-2Aadult progenitor cells.
Authors: Wren D , Wolswijk G , Noble M
Published: May 2004

We have been studying the differing characteristics of oligodendrocyte-type-2 astrocyte (O-2A) progenitors isolated from optic nerves of perinatal and adult rats. These two cell types display striking differences in their in vitro phenotypes. In addition, the O-2Aperinatal progenitor population appears to have a limited life-span in vivo, while O-2Aadult progenitors appear to be maintained throughout life. O-2Aperinatal progenitors seem to have largely disappeared from the optic nerve by 1 mo after birth, and are not detectable in cultures derived from optic nerves of adult rats. In contrast, O-2Aadult progenitors can first be isolated from optic nerves of 7-d-old rats and are still present in optic nerves of 1-yr-old rats. These observations raise two questions: (a) From what source do O-2Aadult progenitors originate; and (b) how is the O-2Aadult progenitor population maintained in the nerve throughout life? We now provide in vitro evidence indicating that O-2Aadult progenitors are derived directly from a subpopulation of O-2Aperinatal progenitors. We also provide evidence indicating that O-2Aadult progenitors are capable of prolonged self renewal in vitro. In addition, our data suggests that the in vitro generation of oligodendrocytes from O-2Aadult progenitors occurs primarily through asymmetric division and differentiation, in contrast with the self-extinguishing pattern of symmetric division and differentiation displayed by O-2Aperinatal progenitors in vitro. We suggest that O-2Aadult progenitors express at least some properties of stem cells and thus may be able to support the generation of both differentiated progeny cells as well as their own continued replenishment throughout adult life.