bluuebunny/crossref_metadata_2025_split huggingface dataset:
The digestive process of the dinoflagellate, Oxyrrhis marina Dujardin, feeding on the chlorophyte, Dunaliella primolecta Butcher: a combined study of ultrastructure and free amino acids
Authors: ÖPIK H. , FLYNN K. J. 
Published: December 2006

SUMMARYThe digestive process of Oxyrrhis marina Dujardin feeding on Dunaliella primolecta Butcher commences with the capture of the phototroph, perhaps involving trichocysts which restrain the prey, followed by engulfing by a membrane that appears to originate from near the fiagella pit of the O. marina. The prey, still within the capture membrane, enters the O. marina and is digested over a period estimated to be of the order of 12‐24h. During digestion the prey first becomes more electron dense and the contents coagulate. Later the prey becomes less distinct and disintegrates; by this stage remains from several prey may be enclosed within one vacuole. Small O. marina, captured by large prey‐depleted O. marina, suffer the same fate. Absence of any correlation between changes in intracellular amino acids and digestion of prey probably resulted from each O. marina containing several prey at various stages of digestion. However, the value of the glutamine/glutamate (Gln/Glu) ratio remained at around 0‐3, whilst the population changed from one dominated by N‐replete D. primolecta to one dominated by prey‐replete O. marina, N‐deplete D. primolecta and prey‐deplete O. marina both have Gln/Glu of < 0.1. The Gln/Glu ratio may therefore be of use in assessing the nutrient status of heterotrophic microflagellates.
BRAIN RECOVERY FROM ESSENTIAL FATTY ACID DEFICIENCY IN DEVELOPING RATS 1
Authors: White H. B. , Galli C. , Paoletti R. 
Published: December 2006

Abstract— Rats were supplied from before birth with an essential fatty acid (EFA) deficient, a control, or an EFA deficient‐control combination diet for various periods up to 6 months.It was found that EFA deficiency resulted in brain weights decreased in comparison with control values throughout development. The brain weight/body weight relationship, however, expressed by Donaldson's equation was generally maintained in animals fed either totally deficient or control diets. Animals deficient even during the brain's most actively growing period were able to recover completely on restoration of the control diet for a sufficiently long period.Fatty acid alterations in brain ethanolamine phosphoglyceride (EPG) during EFA deficiency were extensive. Acids of the ω6 family (18:2, 20:2, 20:3, 20:4, 22:3, 22:4 but not 22:5) were reduced from control figures. In the w9 family 20:3 and 22:3 were especially elevated whereas 22:6 ω3 levels were similar to those of the controls, finally decreasing only after a lengthy period of EFA deprivation. Mean unsaturation contents, as expressed by the proposed unsaturation index notation (Ulmol) agreed closely in EPG fatty acids of deficient and control rats at a particular age. On substitution of the control for the deficient diet the ω6 family rebounded in a manner such that values for 20:4, 22:4, and 22:5 exceeded comparable figures in control animals. Concomitantly the ω9 family receded below control levels, and ω3 acids remained or returned to normal. This overadjustment in ω6 and ω9 families continued even after a prolonged period on the control diet.
THE EFFECT OF DEFICIENCY OF THIAMINE ON THE METABOLISM OF [U‐14C]GLUCOSE AND [U‐14C]RIBOSE AND THE LEVELS OF AMINO ACIDS IN RAT BRAIN
Authors: Gaitonde M. K. , Nixey R. W. K. , Sharman I. M. 
Published: December 2006

Abstract— The incorporation of 14C into amino acids of the brain was determined at different times after injection of [U‐14C]glucose and [U‐14C]ribose to rats maintained on thiamine‐supplemented and thiamine‐deficient diets for 22 days.The 14C‐content of amino acids in the brain of thiamine‐deficient rats decreased at times 2–10 min after injection of [U‐14C]glucose. but it increased at 2 min and decreased at times 5–10 min after injection of [U‐14C]ribose.The results of labelling of amino acids indicated that the activities in vivo of the thiamine pyrophosphate requiring enzymes, pyruvate oxidase, a‐oxoglutarate dehydrogenase and transketolase were similar in the two groups. It was suggested that the observed decrease in the labelling of amino acids was due to one or more of the following factors: (i) a decrease in the activities of glycolytic enzymes catalysing the conversion of glucose into triose phosphate; (ii) a decrease in the transport of substrate to the active site of the enzymes; or (iii) altered neurohistopathology of the brain.Thiamine deficiency in rats showed a 5% decrease in glutamate (P < 0–05), 46% decrease in threonine (P < 0001) and 16% increase in glycine (P < 0–01) content of the brain.
SOME PARAMETERS AFFECTING THE ACTIVITY OF MONOAMINE OXIDASE IN PURIFIED BOVINE BRAIN MITOCHONDRIA 1
Authors: Gabay Sabit , Achee Frances M. , Mentes Gülriz 
Published: December 2006

Abstract— Some parameters affecting the activity of monoamine oxidase (MAO) in purified beef brain mitochondria were investigated, and diversities in enzyme properties were found as a function of substrate. The deamination of the biogenic amines: serotonin, dopamine, tyramine, tryptamine, phenylethylamine and two non‐physiological amines, kynuramine and m‐iodobenzylamine, was studied. Anions in high concentrations inhibited enzyme activity with kynuramine being the substrate most affected. Among the biogenic amines, the activity with the indolalkylamines showed greater sensitivity to mono‐valent anions such as chloride than to polyvalent ions such as phosphate whereas the opposite was true with the phenylalkylamines. However, pyrophosphate ion had little or no effect on MAO activity, regardless of substrate. The inhibition of kynuramine and serotonin deamination was non‐competitive but mixed competitive inhibition was found with tyramine and phenylethylamine.The activity of MAO was markedly affected by pH, and it had been previously reported that the substrates showed different pH optima in their oxidation. The effect of pH on activity has been attributed in part to changes in the ionization of the substrate and the hypothesis that the true substrate is the non‐protonated amine. This was reflected in kinetic studies showing high substrate inhibition with increased pH. It was calculated that phenylethylamine would have the highest percentage of un‐ionized amine at pH 8.2 and 9.1. At these pHs, there was more pronounced inhibition with high substrate concentrations of phenylethylamine than with the other substrates. In contrast, there was little inhibition with high substrate concentrations of tyramine which was the most ionizable of the substrates tested. When Km values obtained at pH 7.4, 8.2 and 9.1 were corrected for ionization of the substrate, the corrected Km was lowest at pH 7.4 for all substrates.Less than 50% of MAO activity was lost when beef brain mitochondria was heated at 50°C for 20 min. However, there was only a slight variation with substrate in the thermal inactivation experiments. It is concluded that the mitochondrial membrane environment surrounding the enzyme imposes certain restrictions on the enzymatic activity with respect to the different substrates which, in turn, are also affected by such parameters as pH and ions. The results are discussed in terms of the relationship of these factors to the question of enzyme multiplicity.
A COMPARISON OF METHODS FOR STOPPING INTERMEDIARY METABOLISM OF DEVELOPING RAT BRAIN1
Authors: Miller A. L. , Shamban Ava 
Published: December 2006

Abstract— Freeze‐blowing (Veechet al. 1973), focussed microwave irradiation (Stavinohaet al. 1973) and immersion in liquid nitrogen were compared as methods for stopping metabolism in order to assay in vivo levels of intermediary metabolites in developing rat brain. Freeze‐blowing was superior at all ages (5. 10, 15 and 20 days post‐natal). The differences between this method and immersion in liquid nitrogen were quite small in the youngest rats and increased with age. reflecting the increased time needed to freeze larger brains. Brains frozen by immersion in liquid nitrogen showed evidence of increased anaerobic metabolism, with increased fructose 1.6‐diphosphate. dihydroxyacetone phosphate and lactate and decreased glucose 6‐phosphate and creatine phosphate concentrations. When brain metabolism was stopped by microwave irradiation there were many differences from freeze‐blown brain. Increases in fructose 1.6‐diphosphate. dihydroxyacetone phosphate, ADP and AMP, and decreased in ATP and creatine phosphate were especially striking. The differences between microwave irradiation and freeze‐blowing were not attributable simply to anoxia. Rather, the changes produced by this method seem to reflect the different thermal characteristics of the various enzymes which must be denatured to stop metabolism of the substrates measured. Unlike freezing in liquid nitrogen, the efficacy of microwave irradiation was not a simple function of head size, in that better results were achieved with 15‐ and 20‐day‐old than 5‐ or 10‐day‐old rats.Many glycolytic and Krebs cycle intermediates, as well as glutamate and aspartate, progressively increased over the course of development. The reasons for these increases are uncertain but are probably‐related to the concomitant rises in rates of glycolysis and oxidative phosphorylation in brain.
A ROLE FOR THIAMINE IN THE REGULATION OF FATTY ACID AND CHOLESTEROL BIOSYNTHESIS IN CULTURED CELLS OF NEURAL ORIGIN1
Authors: Volpe J. J. , Marasa J. C. 
Published: December 2006

Abstract— Cultured glial (C‐6) and neuronal (neuroblastoma) cells were utilized to define the role of thiamine in the regulation of fatty acid and cholesterol biosynthesis. Glial cells subjected to thiamine deficiency exhibited rates of fatty acid synthesis that were only 13% of the rates in thiamine‐supple‐mented cells. The decrease in fatty acid synthetic rate was accompanied by a comparable decrease in the activities of fatty acid synthetase and acetyl‐CoA carboxylase, the two critical enzymes in the pathway. Immunochemical techniques demonstrated that the decrease in activity of fatty acid synthetase reflected a decrease in enzyme content and that this change in content was caused by a decrease in enzyme synthesis. The disturbance of fatty acid synthesis was exquisitely sensitive to thiamine–i.e. marked improvement was evident within hours of replenishment with only 0.01 μ/ml of thiamine. Total recovery occurred in 1–2 days. Thiamine‐deficient glia also exhibited reduced rates of cholesterol biosynthesis, i.e. 60% of the rates in thiamine‐supplemented cells. This effect was accompanied by a comparable reduction in activity of 3‐hydroxy‐3‐methylglutaryl‐CoA (HMG‐CoA) reductase, the rate‐limiting step in cholesterol biosynthesis. Unlike the glial cells, the neuronal cells exhibited either no or only a slight reduction in lipid synthesis under similar conditions of thiamine deficiency.The data have important implications for the genesis of the neuropathology in states of altered thiamine homeostasis and for the mechanisms of regulation of lipid synthesis.
EFFECTS OF ELEVATED [K+]0 ON THE RELEASE OF NEUROTRANSMITTERS FROM CORTICAL SYNAPTOSOMES: EFFLUX OR SECRETION?
Authors: Haycock John W. , Levy William B. , Denner Larry A. , Cotman Carl W. 
Published: December 2006

Abstract— Elevated K+0 elicited a substantial Ca‐independent efflux of accumulated GABA from cortical synaptosomal fractions. Efflux from tissue labelled with either NE or choline was affected considerably less by elevated K+ pulses in the absence of calcium. K‐facilitated Ca‐dependent efflux was large for all three of the accumulated substances. K‐dependent (Ca‐independent) efflux of accumulated GABA was associated with all subcellular fractions exhibiting GABA accumulation whereas K‐facilitated Ca‐dependent efflux was restricted to fractions containing synaptosomes. Eighty per cent of both GABA accumulation and K‐dependent efflux was, however, recovered in a purified synaptosomal fraction. Alanine slightly decreased GABA accumulation, but % K‐dependent efflux was not affected.Elevated K+, in the absence of calcium, released GABA from accumulated pools in preference to endogenous pools, whereas the Ca‐dependent efflux, facilitated by K+, was similar for both accumulated and endogenous GABA.The Ca‐independent efflux of accumulated GABA increased linearly with log [K+]0 between 10 and 70 mM‐K+ in sodium‐containing media. Prior treatment with veratridine or Na‐free medium substantially decreased the Ca‐independent but not the Ca‐dependent GABA efflux produced by elevated K+ pulses.The Ca‐dependent and Ca‐independent efflux of accumulated GABA in response to elevated K+ pulses is suggested to arise not only via different flux mechanisms but also from different GABA pools. The Ca‐dependent efflux is interpreted to reflect stimulus‐secretion coupling processes whereas the Ca‐independent efflux may reflect membrane transport processes.
REGIONAL LEVELS OF GABA IN THE BRAIN: RAPID SEMIAUTOMATED ASSAY AND PREVENTION OF POSTMORTEM INCREASE BY 3‐MERCAPTO‐PROPIONIC ACID
Authors: van der Heyden J. A. M. , Korf J. 
Published: December 2006

Abstract— A simple and rapid semiautomated assay for GABA in central nervous tissue is described. The method is based on a simple manual procedure of isolating GABA from tissue extracts on small CM Sepharose Cl 6B columns, followed by an automated fluorimetric detection (continuous flow system) with o‐phthalaldehyde (OPA) and β‐mercapto‐ethanol (β‐ME) at an alkaline pH. GABA is separated from other compounds that fluoresce in our detection system. By using low concentration of OPA and β‐ME and allowing only a short reaction time with these reagents, the detection is specific towards GABA. The detection limit of the assay is 1 nmol.A procedure is described for the prevention of postmortem GABA increase in rat and mouse brain by intravenous injection of 3‐mercapto‐propionic acid (1.2 nmol/kg) 2min before decapitating the animal. This treatment and microwave irradiation result in similar GABA levels in mouse brain and substantia nigra tissue from rat brain. We found a great conformity in regional GABA levels in the rat and the mouse brain.
Effect of Meniscal Release on Rate of Subsequent Meniscal Tears and Owner‐Assessed Outcome in Dogs with Cruciate Disease Treated with Tibial Plateau Leveling Osteotomy
Authors: THIEMAN KELLEY M. , TOMLINSON JAMES L. , FOX DEREK B. , COOK CRISTI , COOK JAMES L. 
Published: December 2006

Objective— To determine and compare rates of meniscal tears after tibial plateau leveling osteotomy (TPLO) among 3 groups of dogs based on treatment method: arthrotomy with meniscal release (openR), arthrotomy without meniscal release (openNR), arthroscopy without meniscal release (scopeNR), and compare long term owner‐assessed outcomes for the same groups.Study Design— Retrospective cohort study.Sample Population— Stifles (n=254) of dogs that had TPLO.Methods— The three groups were compared for significant (P<.05) differences in rate of subsequent tears using a χ2 test. Odds ratios for likelihood of subsequent meniscal tears were determined. Data for signalment, outcome, time to peak function, and time to subsequent tear were compared for significant differences using ANOVA, t‐test, or rank sum test.Results— Subsequent meniscal tears were diagnosed in 16 cases (6.3%). Of dogs with subsequent meniscal tears, 9 had openNR, 4 had openR, and 3 had scopeNR; the proportion of subsequent meniscal tears was significantly different (P=.035) among groups. Odds ratio indicated that subsequent meniscal tear was 3.8 times more likely to occur for openNR than openR or scopeNR. No significant differences among groups were noted for measures of outcome.Conclusions— Meniscal release did not reduce the rate of subsequent meniscal tears when compared with cases treated arthroscopically or when compared with all cases combined, but may be advantageous when meniscal pathology cannot be comprehensively assessed in the cranial cruciate deficient stifle. Meniscal release had no effects on owner‐assessed outcome as determined in this study.Clinical Relevance— The low rates of subsequent meniscal tears in conjunction with the relatively high and equivocal levels of owner‐assessed outcome and time to peak function for all 3 treatment groups suggest that any of these surgical management strategies can be considered acceptable. We suggest that a meniscal release be performed when complete and thorough exploration of the joint and meniscus cannot be, or are not, performed.
In Vivo Evaluation of Intra‐Articular Protection in a Novel Model of Canine Cranial Cruciate Ligament Mid‐Substance Elongation Injury
Authors: LOPEZ MANDI J. , ROBINSON SANDRA O. , QUINN MARGARET M. , HOSGOOD GISELLE , MARKEL MARK D. 
Published: December 2006

Objectives—To evaluate the effects of intra‐articular protection (IAP) on the canine cranial cruciate ligament (CrCL) and stifle in a CrCL midsubstance elongation injury model.Study Design—Experimental longitudinal cohort study.Animals—Skeletally mature female mixed breed hounds (n=12; mean±SEM weight, 25.6±0.7 kg).Methods—After CrCL elongation in 1 stifle of each dog, IAP was applied in 6 joints. In vivo assessment included radiographs, cranial–caudal joint translation, gait analysis, and synovial fluid levels of 3B3(−) (proteoglycan epitope) and C2C (collagen II neoepitope) up to 12 weeks after surgery. Joint translation and rotation were quantified at necropsy. CrCL midsubstance length was determined before and after elongation and at necropsy. CrCLs were subjectively assessed with light microscopy. Comparisons were made between stifles containing elongated CrCLs with and without IAP and unoperated controls.Results—Four weeks after surgery, ground reaction forces were significantly decreased in operated limbs. Absolute C2C levels were significantly elevated in operated stifles 4 weeks post‐surgery. C2C and 3B3(−) levels normalized to total protein were significantly elevated in IAP+ stifles 8 weeks after surgery. Protected CrCLs appeared to have decreased granulation tissue and better collagen fiber alignment.Conclusions—IAP has negligible effects on the canine stifle based on the response variables evaluated in this 12‐week study. Protection of elongated CrCLs may promote reduced, organized scar formation.Clinical Relevance—These results support the healing capacity of the canine CrCL midsubstance following elongation injury and IAP application to potentially reduce cicatrix formation in elongated CrCLs.
Estimating the risk of pressure ulcer development: is it truly evidence based?
Authors: Sharp Catherine A , McLaws Mary‐Louise 
Published: December 2006

AbstractThe aim of the current method of screening patients is to identify risk factors that are considered to cause, or contribute to, pressure ulcer (PU) development. Yet screening has not resulted in a reduction in pressure ulcer development. The literature was reviewed to identify the level of evidence for the inclusion of risk factors in six published pressure ulcer risk‐screening tools. Evidence for each risk factor was ranked according to the National Health and Medical Research Council levels of evidence with a modification. Three of 19 risk factors (mobility, continence and nutrition) included in more than one screening tool have been tested for association with pressure ulcer development. While varying degrees of immobility and decreased serum albumin are reported to significantly increase the risk for PU development, the direction of the relationship, i.e. causal or resultant of PU, is not always clear. No publications reported a significant causal link between incontinence and PU development. Inclusion of risk factors for PU in screening tools must be evidence based. Until other risk factors have been tested for positive predictive value, the Ramstadius approach to screening is the only evidence‐based tool.
The potential of microscopic sterile sponge particles to induce foreign body reaction
Authors: Sari Alper , Basterzi Yavuz , Karabacak Tuba , Tasdelen Bahar , Demirkan Ferit 
Published: December 2006

AbstractThe sterile sponges may lose a significant amount of lint during their routine use in surgery, which is usually neglected. We designed an experimental model to evaluate the potential of sterile sponges to lose lint and to induce foreign body reaction in surgically created wounds. In 15 Wistar rats, separate subcutaneous pockets were created. Left‐sided pockets were temporarily packed with sterile sponges, while the right‐sided pockets remained empty. All the pockets were then irrigated with sterile saline. The presence of microscopic sponge particles was evaluated in the irrigation materials. After 4 weeks, the presence of inflammation and foreign body reaction were evaluated histologically. Microscopic sponge remnants were present in 14 of 15 samples collected from the left sides. The presence of foreign body giant cells with ingested sponge particles and formation of well‐defined foreign body granulomas were observed only in samples collected from the left sides. A statistically significant difference was observed between the two sides when the intensity of inflammation was graded (P= 0·012). Cotton sponges used in surgery are shown to have a potential of losing invisible microscopic particles that have a potential to induce foreign body reaction.
Silver dressings: their role in wound management
Authors: Leaper David J 
Published: December 2006

AbstractDressings have a part to play in the management of wounds; whether they are sutured or open, usually chronic wounds of many aetiologies which are healing by secondary intention. They traditionally provide a moist wound environment, but this property has been extended through simple to complex, active dressings which can handle excessive exudate, aid in debridement, and promote disorganised, stalled healing. The control of infection remains a major challenge. Inappropriate antibiotic use risks allergy, toxicity and most importantly resistance, which is much reduced by the use of topical antiseptics (such as povidone iodine and chlorhexidine). The definition of what is an antimicrobial and the recognition of infection has proven difficult. Although silver has been recognised for centuries to inhibit infection its use in wound care is relatively recent. Evidence of the efficacy of the growing number of silver dressings in clinical trials, judged by the criteria of the Cochrane Collaboration, is lacking, but there are good indications for the use of silver dressings, to remove or reduce an increasing bioburden in burns and open wounds healing by secondary intention, or to act as a barrier against cross contamination of resistant organisms such as MRSA. More laboratory, and clinical data in particular, are needed to prove the value of the many silver dressings which are now available. Some confusion persists over the measurement of toxicity and antibacterial activity but all dressings provide an antibacterial action, involving several methods of delivery. Nanocrystalline technology appears to give the highest, sustained release of silver to a wound without clear risk of toxicity.