bluuebunny/crossref_metadata_2025_split huggingface dataset:
Targeting energy metabolism in brain cancer: review and hypothesis
Authors: Seyfried Thomas N , Mukherjee Purna 
Published: October 2005

AbstractMalignant brain tumors are a significant health problem in children and adults and are often unmanageable. As a metabolic disorder involving the dysregulation of glycolysis and respiration, malignant brain cancer is potentially manageable through changes in metabolic environment. A radically different approach to brain cancer management is proposed that combines metabolic control analysis with the evolutionarily conserved capacity of normal cells to survive extreme shifts in physiological environment. In contrast to malignant brain tumors that are largely dependent on glycolysis for energy, normal neurons and glia readily transition to ketone bodies (β-hydroxybutyrate) for energyin vivowhen glucose levels are reduced. The bioenergetic transition from glucose to ketone bodies metabolically targets brain tumors through integrated anti-inflammatory, anti-angiogenic, and pro-apoptotic mechanisms. The approach focuses more on the genomic flexibility of normal cells than on the genomic defects of tumor cells and is supported from recent studies in orthotopic mouse brain tumor models and in human pediatric astrocytoma treated with dietary energy restriction and the ketogenic diet.
Contrasting Phenotypes of Putative Proprioceptive and Nociceptive Trigeminal Neurons Innervating Jaw Muscle in Rat
Authors: Connor Mark , Naves Ligia A , McCleskey Edwin W 
Published: October 2005

Background: Despite the clinical significance of muscle pain, and the extensive investigation of the properties of muscle afferent fibers, there has been little study of the ion channels on sensory neurons that innervate muscle. In this study, we have fluorescently tagged sensory neurons that innervate the masseter muscle, which is unique because cell bodies for its muscle spindles are in a brainstem nucleus (mesencephalic nucleus of the 5th cranial nerve, MeV) while all its other sensory afferents are in the trigeminal ganglion (TG). We examine the hypothesis that certain molecules proposed to be used selectively by nociceptors fail to express on muscle spindles afferents but appear on other afferents from the same muscle. Results: MeV muscle afferents perfectly fit expectations of cells with a non-nociceptive sensory modality: Opiates failed to inhibit calcium channel currents ( ICa) in 90% of MeV neurons, although ICa were inhibited by GABAB receptor activation. All MeV afferents had brief (1 msec) action potentials driven solely by tetrodotoxin (TTX)-sensitive Na channels and no MeV afferent expressed either of three ion channels (TRPV1, P2X3, and ASIC3) thought to be transducers for nociceptive stimuli, although they did express other ATP and acid-sensing channels. Trigeminal masseter afferents were much more diverse. Virtually all of them expressed at least one, and often several, of the three putative nociceptive transducer channels, but the mix varied from cell to cell. Calcium currents in 80% of the neurons were measurably inhibited by μ-opioids, but the extent of inhibition varied greatly. Almost all TG masseter afferents expressed some TTX-insensitive sodium currents, but the amount compared to TTX sensitive sodium current varied, as did the duration of action potentials. Conclusion: Most masseter muscle afferents that are not muscle spindle afferents express molecules that are considered characteristic of nociceptors, but these putative muscle nociceptors are molecularly diverse. This heterogeneity may reflect the mixture of metabosensitive afferents which can also signal noxious stimuli and purely nociceptive afferents characteristic of muscle.
Development of a method for the measurement of dehydroepiandrosterone sulphate by liquid chromatography-tandem mass spectrometry
Authors: Chadwick C A , Owen L J , Keevil B G 
Published: October 2005

Background: Dehydroepiandrosterone sulphate (DHEAS) is a steroid that is increasingly being recognized as a potential drug of abuse in many countries. This is due to its reputation as a hormone that may be able to retard the ageing process. The measurement of DHEAS is useful in the diagnosis of medical conditions such as congenital adrenal hyperplasia and polycystic ovary syndrome. Thus, a liquid chromatography-tandem mass spectrometry method has been developed to determine DHEAS concentrations in human serum. Method: The chromatography was performed using a WatersTM 2795 Alliance HT LC system coupled to a Mercury Fusion-RP column fitted with a SecurityGuardTM column. Results: DHEAS and the internal standard, deuterated DHEAS, both had a retention time of 1.5 min. The transition determined by the Micromass QuattroTM tandem mass spectrometer for DHEAS was m/z 367.3>96.7 and for the internal standard m/z 369.3>96.6. The method was linear up to 20 µmol/L; the lower limit of detection and the lower limit of quantitation were both 1 µmol/L. The intra- and interassay imprecision were <11% over a concentration range of 1-18 µmol/L for the in-house quality control and <12% for the intra- and interassay imprecision for the Bio-Rad Lyphocheck QC. Conclusion: The measurement of DHEAS by liquid chromatography-tandem mass spectrometry is robust and has a simple sample preparation procedure with a rapid cycle time of only 4 min.
Erythrocyte zinc in hospital patients
Authors: Batchat L , Vaja S , Treacher D , Kinerons M , Swaminathan R 
Published: October 2005

Background: Abnormal thyroid function tests (serum thyrotropin [TSH], free thyroxine [T4] and free triiodothyronine [T3]) are frequently seen in hospitalized patients. Assessment of thyroid function in these patients is difficult. It has been suggested that acutely ill patients may be hypothyroid at the tissue level. Erythrocyte zinc (EZn) has been shown to be increased in hypothyroidism. The aim of this study was to examine EZn as an index of thyroid status of hospital patients. Methods: In order to assess the thyroid status at tissue level, we measured EZn in 26 healthy subjects, 39 critically ill patients and 19 hospitalized geriatric patients. EZn was measured in young cells, as the effect of illness is likely to be seen in the newly formed cells. Result: TSH and free T3 were lower in critically ill patients and serum free T3 was lower in geriatric patients. EZn in young cells was higher in both patient groups (by 13% and 23%, respectively). EZn in old cells was also higher in the geriatric group. Conclusion: We conclude that EZn is higher in hospitalized patients, suggesting that these patients may be hypothyroid at the tissue level.
Do we need lipid clinics? Shifting the balance between secondary and primary care
Authors: Stuart W , Smellie A 
Published: October 2005

Background: Increasing activity in cholesterol lowering is placing increasing demands on lipid clinics to be able to cope with the increase in demand. A combination of interventions has been used to improve laboratory testing, focus interpretative results and provide educational and advisory facilities for general practitioners in order to increase shared care of many potential clinic patients. Methods: Retrospective study of clinic waiting times, results in patients managed on a shared care basis, and overall clinical activity over a three-and-a-half-year intervention period between March 2001 and August 2004 in a single-consultant, single-centre secondary care clinic serving three primary care trusts, covering a population of approximately 270,000 people. The interventions involved a change to the laboratory request form, outreach educational meetings and promotion of use of 'written advice only' for certain patients as an alternative to direct clinic referral. The main outcome measures were percentages of patients followed up in primary care, change in cholesterol and triglyceride results after advice, and clinic waiting time. Results: A total of 520 patients were referred over three and a half years, either to be seen or for written advice only. About 291 of these were handled by advisory letters. In all, 90% of these patients were already receiving or had received lipid-lowering therapy at the time of referral. 98% of patients were followed up by their general practice post-advice. Cholesterol and triglyceride concentrations fell by 23% and 39%, respectively, post-advice. Waiting times fell from a peak of 35 weeks before the interventions to an average of three weeks after. This fall has been maintained over the three-and-a-half years the intervention has run. Conclusions: The interventions have resulted in a large fall in clinic waiting times, improvement in lipid results, and high rate of general practice follow-up, all of which have been sustained in the long term.
Detection assessment and monitoring of hepatic fibrosis: biochemistry or biopsy?
Authors: Mardini H , Record C 
Published: October 2005

Hepatic fibrosis is an important consequence of inflammatory disorders affecting the liver, and ultimately progresses to cirrhosis. Here we explore methods for the detection and monitoring of hepatic fibrosis, particularly in hepatitis C, alcoholic liver disease, non-alcoholic fatty liver disease and during methotrexate therapy, in all of which progressive fibrosis can develop over a number of years in a minority of patients. Liver biopsy currently remains the gold standard to assess fibrosis. However, it has several limitations, including manpower issues, cost, risk of patient injury, including mortality and morbidity, observer variability and sampling variation. Several non-invasive diagnostic tests for fibrosis and cirrhosis have therefore been evaluated. The usefulness of a laboratory test for screening for a pathological abnormality such as fibrosis is critically dependent on the prevalence of the pathology in the population under investigation. When the prevalence is expected to be low, screening tests should have a high negative predictive value so that large numbers of patients can be spared the next diagnostic step, namely liver biopsy. For the moment, clinical chemistry laboratories should offer the aspartate aminotransferase alanine aminotransferase ratio, AST/platelet ratio and the Rosenberg fibrosis index as part of their routine service for monitoring the development of hepatic fibrosis.
The influence of genetic and environmental factors on plasma homocysteine concentrations in a population at high risk for coronary artery disease
Authors: Bowron Ann , Scott Jeff , Stansbie David 
Published: October 2005

Background: Elevated plasma total homocysteine (tHcy) predisposes to vascular disease and results from interactions between genetic and nutritional factors. MTHFR C677T increases tHcy in association with low folate. CBS 844ins68 lowers tHcy and negates the raising effect of MTHFR C677T in healthy subjects, but it is unclear if this is the case in subjects at high risk of vascular disease. This study examines the effect on plasma tHcy of interactions between these polymorphisms in an at-risk group. Methods: Blood samples were collected from 376 subjects at increased risk of coronary artery disease. Plasma tHcy and vitamin B6 were measured by HPLC and red cell folate and serum vitamin B12 were measured by immuno-luminometric assay. MTHFR C677T and CBS 844ins68 status was established by standard PCR techniques. Results: MTHFR TT predisposed to hyperhomocysteinaemia; this was increased in the presence of low folate ( P<0.05) and vitamin B12 ( P<0.01). An inverse relationship was found between tHcy and folate ( r= -0.42, P<0.0001), vitamin B12 ( r= -0.26, P<0.0005) and vitamin B6 ( r= -0.25, P<0.01). There was no interaction between plasma tHcy, vitamins or MTHFR C677T and CBS 844ins68. Discussion: In this population at high risk of coronary artery disease, plasma tHcy was determined by vitamin status. This was exacerbated by the MTHFR C677T mutation. CBS 844ins68 did not influence tHcy and did not negate the tHcy-raising effect of MTHFR C677T.
Interference of ascorbic acid with chemical analytes
Authors: Meng Qing H , Irwin William C , Fesser Jennifer , Massey K Lorne 
Published: October 2005

Background: Ascorbic acid can interfere with methodologies involving redox reactions, while comprehensive studies on main chemistry analysers have not been reported. We therefore attempted to determine the interference of ascorbic acid with analytes on the Beckman Synchron LX20®. Methods: Various concentrations of ascorbic acid were added to serum, and the serum analytes were measured on the LX20. Results: With a serum ascorbic acid concentration of 12.0 mmol/L, the values for sodium, potassium, calcium and creatinine increased by 43%, 58%, 103% and 26%, respectively ( P<0.01). With a serum ascorbic acid concentration of 12.0 mmol/L, the values for chloride, total bilirubin and uric acid decreased by 33%, 62% and 83%, respectively ( P<0.01), and were undetectable for total cholesterol, triglyceride, ammonia and lactate. There was no definite influence of ascorbic acid on analytical values for total CO2, urea, glucose, phosphate, total protein, albumin, amylase, creatine kinase, creatine kinase-MB, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total iron, unbound iron-binding capacity or magnesium. Conclusions: Ascorbic acid causes a false increase in sodium, potassium, calcium and creatinine results and a false decrease in chloride, total bilirubin, uric acid, total cholesterol, triglyceride, ammonia and lactate results.
Potential pitfalls in intraoperative parathyroid hormone measurements during parathyroid surgery
Authors: Phillips IJ , Kurzawinski TR , Honour JW 
Published: October 2005

Background: The outcome of parathyroid surgery is often not clear for at least 24 h after the operation. A frozen section does not always distinguish between an adenoma and hyperplasia. Minimally invasive surgical techniques are being refined, so the need for perioperative assurance about the completeness of surgery has increased. The value of intraoperative parathyroid hormone (PTH) measurements in 26 surgical cases undergoing parathyroidectomy has been evaluated. Methods: Twenty-one patients were diagnosed as having primary hyperparathyroidism, including two patients with multiple endocrine neoplasia type I (MEN I). Five patients had tertiary hyperparathyroidism, including one patient with X-linked hypophosphataemia and four with renal hyperparathyroidism (RHPT). Blood samples were taken at the onset of surgery, at the time of tumour resection and at 5-min intervals following removal of the tumour. PTH was measured using a PTH Turbo assay on the DPC Immulite analyser. Results: Current practice suggests that the PTH concentration should fall to less than 50% of the pre-incision value or to less than 50% of the level at the time of tumour resection (time equals zero). PTH levels were therefore monitored at 5-min intervals following removal of the tumour. In most of the case studies PTH followed the suggested pattern, but not when further exploration was warranted to determine if another adenoma was present. In some cases the PTH levels fell by the appropriate margin to deem the procedure a success but at 10 min post-gland excision the PTH began to rise again. Further exploration was required to confirm the continued source of PTH. Conclusion: We recommend that intraoperative PTH measurements continue until at least 15 min post-gland removal in cases of suspected single-gland disease. A decline in PTH concentration to at least 50% of the pre-incision or time of gland resection levels should be observed. If the PTH remains elevated or rises again after an appropriate decrease in levels, then multigland disease or ectopic sources should be considered. Caution is recommended in interpreting intraoperative PTH measurements to ensure complete success of the surgical procedure.
Illite-Smectite Mixed-Layer Minerals in the Hydrothermal Alteration of Volcanic Rocks: I. One-Dimensional XRD Structure Analysis and Characterization of Component Layers
Authors: Inoue Atsuyuki , Lanson Bruno , Marques-Fernandes Maria , Sakharov Boris A. , Murakami Takashi , Meunier Alain , Beaufort Daniel 
Published: October 2005

AbstractFor a series of mixed-layer illite-smectite (I-S) minerals from a drillhole near the Kakkonda geothermal field, one-dimensional structure analysis by X-ray diffraction (XRD) was performed using Casaturated specimens in both air-dried and ethylene glycol-solvated states. The expandability characteristics of component layers were also examined by means of alkylammonium exchange and Li saturation. The K content in the illite layers was 1.5–1.7/O20(OH)4 in the I-S series from 3 to 85% of I-layer content (% I). The layer charge of the smectite layer varied slightly within the range of 0.3–0.5/O10(OH)2 by alkylammonium exchange experiments and the expandability was independent of the beidellite content within a range of 0–0.5 by the Li-saturation test. The degree of long-range ordering represented by Reichweite (R) parameters varied from R0 to R3 via R1 and R2 with increase in % I. The I-S samples contained <10% vermiculite as the third component and the vermiculite content tended to decrease with progressive illitization.In contrast to the smectitic R0 samples (<10% I), more illitic R0 (e.g. 35% I) and >R1 I-S samples showed complicated expandability with alkylammonium exchange. The XRD patterns of dodecylammonium-exchanged I-S samples can be interpreted by random interstratification of several types of sub-units such as layer-doublets, layer-triplets and layer-quartets present in the crystallites. This interpretation is consistent with the variation in the occurrence probabilities of layer-multiplets calculated from the junction probabilities and the proportions of layers. Because the interpretation indicates that I-S is a stack of various types of the sub-units, the smectite illitization can be described by a systematic change in the type and proportion of the sub-units constituting crystallites.
Illite-Smectite Mixed-Layer Minerals in the Hydrothermal Alteration of Volcanic Rocks: II. One-Dimensional HRTEM Structure Images and Formation Mechanisms
Authors: Murakami Takashi , Inoue Atsuyuki , Lanson Bruno , Meunier Alain , Beaufort Daniel 
Published: October 2005

AbstractSmectite illitization was investigated in felsic volcaniclastic rocks from a drill core near the Kakkonda active geothermal system, Japan, using high-resolution transmission electron microscopy (HRTEM) that provided one-dimensional structure images of mixed-layer illite-smectite (I-S) minerals normal to [M0]. Simulated images of a rectorite-like structure revealed that smectite can be distinguished from illite in mixed-layer I-S by HRTEM if the basal spacing of smectite is larger than that of illite. The larger basal spacing of smectite, 1.3 nm under HRTEM, was obtained by intercalation of dodecylammonium ions into smectitic interlayers. In simulated and observed images normal to [hk0], tetrahedral (T) and octahedral (O) cation planes are imaged as dark lines, an illitic interlayer as a bright line, and a smectitic interlayer as a dark line sandwiched between two bright lines.The samples are from depths of 435 m (5% I; R0), 635 m (35% I; R0), 656 m (62% I; R1), and 756 m (85% I; R3) where % I is the percentage of illite layers in a sample and R is the Reichweite parameter. Sample 435 consisted mostly of smectite, and illite layers occurred, though small in amount, as M1 units (module of type 1, defined as consisting of two polar T-O-T silicate layers with one central illitic interlayer and two, half smectitic interlayers at the outermost surface; the number corresponds to that of central illitic interlayers). The M1 units were dominant and isolated and consecutive smectite layers (>2) were present in sample 635. Sample 656 consisted mostly of packets of M1 units of 1 to 5 layers containing M2 to M5 units occasionally. Isolated or consecutive smectite layers (>2) were not present in 656. Illite layers occurred almost entirely as M1 units in samples 435, 635 and 656, and the number of M1 units increased with increase in % I. Sample 756 was characterized by the presence of M2 to M10 units accompanied by smectitic interlayers at the external surface and the absence of M1 units and isolated smectite layers. The HRTEM data strongly suggest that illitization in a hydrothermal system occurs by precipitation of M1 units for mixed-layer I-S minerals up to 60% I. This does not require the presence of precursor smectite. Illitization of I-S minerals with >60% I proceeds by precipitation of various types of Mn (n ⩾ 2) units. Illite occurs only as Mn (n ⩾ 1) units throughout illitization.
Characterization and Origin of Fe3+-Montmorillonite in Deep-Water Calcareous Sediments (Pacific Ocean, Costa Rica Margin)
Authors: Gaudin A. , Buatier M. D. , Beaufort D. , Petit S. , Grauby O. , Decarreau A. 
Published: October 2005

AbstractMillimetric to centimetric green grains widespread in pelagic calcareous sediments recovered at a water depth of3000 m near the Costa Rica margin were studied by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy. Samples were collected, during the Ticoflux II expedition, from the upper bioturbated part of four sedimentary cores (0.13–3.75 m below seafloor). The sediments are calcareous and siliceous nanofossil oozes (coccoliths, diatoms, radiolarians, etc.).Green grains show generally a concentric zoning with a green rim in which smectite largely predominates over pyrite and a black core in which pyrite is prevalent. Observations by SEM indicate that this zoning results from a progressive inward alteration and replacement of the accumulations of pyrites by smectites. The high-resolution TEM observations of the smectite-pyrite interfaces suggest that the replacement of pyrites by smectite occurs through a dissolution-precipitation process with the formation of a gel. The pyrite matrix is composed of a huge number of very small (0.5–22 µm) pyrite octahedra, a typical texture resulting from the pyritization of organic material in early diagenetic environments.The accurate mineralogical and crystal chemical characterization of the smectites indicate that they are Fe3+-montmorillonites (Fe3+-rich smectite with a dominant octahedral charge, rarely recorded in the literature). The formation of such Fe3+-montmorillonites forming green grains could be explained by two successive diagenetic redox stages: (1) reducing stage: early pyritization of the organic matter by microbial reduction within reducing micro-environments; (2) oxidizing stage: Fe3+-montmorillonite crystallized in space liberated after dissolution of pyrite connected with the rebalancing of the redox conditions of the micro-environments with the oxidizing surrounding sediments.