Search Results - (Author, Cooperation:A. J. Thomas)

2016-01-30

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Animals ; Animals, Genetically Modified ; Carcinogenesis/*genetics ; Embryonic Stem Cells/metabolism ; Enhancer Elements, Genetic ; *Gene Expression Regulation, Developmental ; *Gene Expression Regulation, Neoplastic ; Genes, Reporter ; Green Fluorescent Proteins/genetics ; Melanocytes/metabolism ; Melanoma/*genetics ; Melanoma, Experimental/*genetics ; Mutation ; Nerve Tissue Proteins/genetics ; Neural Crest/*metabolism ; Proto-Oncogene Proteins B-raf/genetics ; SOXE Transcription Factors/genetics ; Skin Neoplasms/*genetics ; Tumor Suppressor Protein p53/genetics ; *Zebrafish ; Zebrafish Proteins/genetics

2015-03-25

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Amino Acid Sequence ; Animals ; Bone and Bones/chemistry ; Cattle ; Collagen Type I/*chemistry/genetics ; Female ; *Fossils ; Mammals/*classification ; Perissodactyla/classification ; *Phylogeny ; Placenta ; Pregnancy ; Proteomics ; South America

2012-01-17

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Capsid/*ultrastructure ; Cryoelectron Microscopy ; DNA, Viral ; Image Processing, Computer-Assisted ; Nucleocapsid/ultrastructure ; Pseudomonas Phages/*chemistry/radiation effects/*ultrastructure ; Viral Proteins/*analysis

2013-10-18

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Animals ; *Biodiversity ; Conservation of Natural Resources/*trends

2018-10-27

Nature Publishing Group (NPG)

2158-3188

Medicine

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract— Mammalian cortical synaptosomes incubated in the presence of glucose (2.5 MM) plus glutamine (0.5 mM) showed a 30% increase in transmitter amino acid content over controls with glucose alone and a doubling of glutamate release induced by Veratrine or high K+. Double-label experiments, i.e. [U-14C]glucose with [3H]glutamine, and single-label experiments, i.e. [U-14C]glucose or [U-14C]-glutamine showed that stimulus-released glutamate was derived principally (80%) from glutamine. Released glutamine-derived glutamate was of higher (x 2) specific radioactivity than its tissue equivalent. Glutamine alone (0.5–0.75 mM) was much less effective than equivalent amounts of glucose alone, in stimulating respiration and maintaining tissue K+ levels.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

: Tityustoxin, the active component of the venom of the Brazilian yellow scorpion Tityus serrulatus, caused specific release of the neurotransmitter amino acids glutamate, aspartate and GABA in vivo from the superfused sensori-motor cortex of conscious unanesthetised rats and in vitro from rat cortical synaptosomes. The effects on synaptosomes appear to be due to a depolarising action. Synaptosomal potassium levels were depleted by the toxin. The action was also blocked both in vivo and in vitro by tetrodotoxin and was Ca2+ -dependent. The uptake of [U-14C]GABA was inhibited by tityustoxin but this action was prevented by tetrodotoxin (1 μm). Since the release of [U-14C]GABA from synaptosomes due to the tityustoxin was also prevented by ietrodotoxin under identical circumstances, it is concluded that the tityustoxin has a primary action on release of neurotransmitters rather than on uptake.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract: The neurochemical effects of the tremorgenic mycotoxins Verruculogen and Penitrem A, which produce a neurotoxic syndrome characterised by sustained tremors, were studied using sheep and rat synaptosomes. The toxins were administered in vivo, either by chronic feeding (sheep) or intraperitoneal injection 45 min prior to killing (rat) and synaptosomes were subsequently prepared from cerebrocortical and spinal cord/medullary regions of rat and corpus striatum of sheep. Penitrem A (400 mg mycelium/kg) increased the spontaneous release of endogenous glutamate, GABA (γ-aminobutyric acid) and aspartate by 213%, 455% and 277%, respectively, from cerebrocortical synaptosomes. Verruculogen (400 mg mycelium/kg) increased the spontaneous release of glutamate and aspartate by 1300% and 1200%, respectively, but not that of GABA from cerebrocortical synaptosomes. The spontaneous release of the transmitter amino acids or other amino acids was not increased by the tremorgens in spinal cord/medullary synaptosomes. Penitrem A pretreatment reduced the veratrine (75 μm) stimulated release of glutamate, aspartate and GABA from cerebrocortical synaptosomes by 33%, 46% and 11%, respectively and the stimulated release of glycine and GABA from spinal cord/ medulla synaptosomes by 67% and 32% respectively. Verruculogen pretreatment did not alter the veratrine-induced release of transmitter amino acids from cerebrocortex and spinal cord/medulla synaptosomes. Penitrem A pretreatment increased the spontaneous release of aspartate, glutamate and GABA by 68%, 62% and 100%, respectively, from sheep corpus striatum synaptosomes but did not alter the synthesis and release of dopamine in this tissue. Verruculogen was shown to cause a substantial increase (300–400%) in the miniature-end-plate potential (m.e.p. p.) frequency at the locust neuromuscular junction. The response was detectable within 1 min, rose to a maximum within 5–7 min and declined to the control rate over a similar period. No change in the amplitude of the m.e.p. p. ‘s was observed. These effects of the tremorgens on transmitter release are interpreted in terms of their mode of action.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

—(1) Synaptosomes incubated in high sodium, low potassium media showed high linear respiration in the presence of glucose which was converted into lactate, aspartate, glutamate, glutamine, alanine and GABA during 1 hr incubation periods.(2) Total conversion of glucose into most of these substrates over the incubation period was similar in synaptosomes and cortex slices. Half the lactate and only a small fraction of the glutamine made by slices was formed by synaptosomes.(3) Pool sizes of amino acids in cortex slices after incubation with glucose were, in general, higher than in synaptosomes, glutamate and glutamine being four-fold higher in slices.(4) Most of the amino acids made from glucose by synaptosomes were contained within their structure and not lost to the medium.(5) Glutamate was actively metabolized by synaptosomes to aspartate, glutamine, alanine and GABA. The specific radioactivities of the amino acids (except glutamine) after 1 hr incubation, approached that of the glutamate.(6) Pyridoxal phosphate added to the incubation medium increased GABA production from glutamate but not from glucose.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

—Potassium causes increased metabolism and release of physiologically active amino acids from suspensions of mammalian synaptosomes. Sheep and rat hypothalamic synaptosomes, and rabbit, sheep and rat cortical synaptosomes show respiratory and glycolytic response to electrical stimulation and show a parallel calcium-dependent differential release of physiologically active amino acids. Attempts were made to eliminate the actions of heating and electrode products as the agents causing the observed effects and the case is made that depolarization is the trigger mechanism.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract: Awake, unrestrained, and behaviourally normal animals with superfusion cannulae implanted over the sensorimotor cortex were used in a study of the capacity of infused [U-14C]glutamine for labelling glutamate and other amino acids released by depolarising stimuli. A spontaneous background release of [14C]glutamate was detected. This was increased by tityustoxin (1 μM). The specific radioactivity of glutamate increased eightfold during the evoked-release period. [14C]Aspartate was also detected and showed increased release, but not increased specific labelling, in response to depolarisation. Evoked γ-aminobutyric acid (GABA) release occurred but only small amounts of [14C]GABA were detected. Glutamine showed increased rates of uptake to the sensorimotor cortex during stimulation periods, suggesting an accelerated breakdown via glutaminase.

Electronic Resource

1747-6593

Blackwell Publishing Journal Backfiles 1879-2005

Energy, Environment Protection, Nuclear Power Engineering

In an attempt to control planktonic algal growth in In an attempt to cosntrol planktonic algal growth in Foxcote water supply reservoir, which is supplied by eutrophic waters from the river Great Ouse, ferric sulphate has been used to reduce ortho-phosphate concentrations in the pumped inlet water. Internal recycling of sediment-bound nutrients retarded the expected algal control for almost three years. During the third year, a marked change in the ecology of the reservoir occurred, and planktonic algae were largely replaced by prolific growths of filamentous species and rooted macrophytes. While the changed flora have caused their own problems, the reservoir is now less prone to closure due to intractable water treatment problems.

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] Table 1 Absorption Compound Maximum Minimum (m//) (m//) cis-trans /?-Chloromuconic acid 264 _ cis-cis Muconic acid 259 2-Hydroxy-4-chlorophenoxyacetic acid 283 255 4-Chloroguiacol 283 255 29-Chlorophenoxyacetie acid 4-Chlorocatechol 280 284 247 250 A hydrogen discharge lamp, similar to ...

Electronic Resource

1573-7330

spermatozoa ; infertility ; ROS ; leukocytospermia ; myeloperoxidase staining ; Endtz test

Springer Online Journal Archives 1860-2000

Medicine

Abstract Purpose Although the significance of leukocytospermia in semen remains controversial, evidence exists that white blood cells (WBCs) may adversely affect sperm function and act as a potential cofactor in male infertility. Nevertheless, the mechanisms by which leukocytes may alter sperm function in vitrois unknown. Recent investigations suggest that reactive oxygen species (ROS) generated by the polymorphonuclear (PMN) granulocytes could adversely affect sperm function. The objective of this study was to investigate the relationship between the presence of leukocytospermia as determined by the Endtz test and the excessive formation of ROS. Methods The WBC concentration and ROS formation in human semen, obtained from men consulting for infertility, were assessed and compared to that of normal donors. ROS was measured by a chemiluminescence assay using luminol and a Berthold luminometer. The WBC concentration was determined with a myeloperoxidase staining technique (Endtz test). Specimens were obtained from 94 subjects (20 donors, 74 patients). Results Of the 20 donors, 2 were Endtz positive and ROS positive; 18 were Endtz negative with 2 (11%) ROS positive. In the patient group (n=74), 26 (35%) were ROS positive, and 17 were Endtz positive and found to be ROS positive. Of the 57 Endtz-negative patients, 9 (15%) were ROS positive. The positive Endtz test results correlated strongly with positive ROS formation in patients and donors (P〈0.001). Conclusions Our results indicate that the simple, costejficient Endtz test could be used as an indicator of excessive ROS formation in semen.

Electronic Resource

1573-7330

cancer patients ; postvasectomy reversal ; idiopathic infertility ; sperm creatine kinase ; varicocele

Springer Online Journal Archives 1860-2000

Medicine

Abstract Purpose: The creatine kinase level indicates sperm maturity and correlates with the spermatozoal fertilizing potential. The relationship between creatine kinase levels in subfertile men and their clinical diagnosis was examined. Methods: Patients with unexplained infertility (n = 34), varicocele (n = 20), postvasectomy reversal (n = 7), or cancer (n = 22) were included in this prospective clinical study. The control group consisted of healthy normal donors (n = 15). Results: The median and interquartile range values of creatine kinase for each group were as follows: normal donors, 0.061 U/10 8 sperm (0.056 to 0.076 U/10 8 sperm); idiopathic malefactor, 0.119 U/10 8 sperm (0.061 to 0.190 U/10 8 sperm); varicocele, 0.392 U/10 8 sperm (0.209 to 1.494 U/10 8 sperm); postvasectomy reversal, 0.589 U/10 8 sperm (0.425 to 4.043 U/10 8 sperm); and cancer, 0.068 U/10 8 sperm (0.047 to 0.168 U/10 8 sperm). Sperm creatine kinase levels were significantly higher in patients with varicocele compared to normal donors (P = 0.0001), cancer patients (P = 0.0002), and men with idiopathic infertility (P = 0.0009). Sperm concentration and creatine kinase level were inversely correlated in patients (r = −0.7,P 〈 0.001) but not in normal donors. Conclusions: Semen quality is poorer in subfertile patients with clinical varicocele and postvasectomy reversal than in cancer patients and patients with idiopathic male infertility. That the creatine kinase levels in cancer patients were similar to those of normal donors suggests that the final phase of spermatogenesis may not be altered in men with cancer; thus semen from these patients should be banked to ensure fertility after cancer treatment.

Electronic Resource

1573-0662

Atmospheric fallout ; water chemistry ; North-western Mediterranean

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Geosciences

Abstract The atmospheric input is established for almost forty trace and major elements at a coastal site on the North-Western Mediterranean. Comparison with the Rhône River input at the scale of the Gulf of Lions shows that the total atmospheric input dominates for elements of anthropogenic origin such as Cd, Pb, Sb and Zn. Dissolved input of atmospheric origin is very important for these elements and for those of terrigenous origin (Al and Fe). In the coastal zone, both dissolved external sources (atmosphere and Rhône River) can explain the high Mediterranean Surface waters concentrations. Atmospheric input becomes rapidly the predominant factor, while the riverine influence being negligible in the few tens' kilometers outside the river mouth.

Electronic Resource

0173-0835

Pulsed-field electrophoresis ; Microlithographic array ; Fractionation ; Chemistry ; Biochemistry and Biotechnology

Wiley InterScience Backfile Collection 1832-2000

Biology

Chemistry and Pharmacology

Transverse pulsed-field electrophoresis of DNA has been conducted in a silicon array engineered by optical lithography and the motion of individual molecules observed by fluorescence microscopy. In strong fields, the molecules can be maintained in highly stretched, linear conformations. When the field is switched through an obtuse angle, they head off in the new direction led by what was formerly their tail end. This backtracking gives rise to fractionation that is linear with molecular weight. A simple prescription exists for choosing the field parameters to obtain a particular range of separation. Since the molecular motions are much more uniform than those that occur in a gel, it is anticipated that the arrays will permit more efficient fractionation than traditional pulsed-field gel electrophoresis. Arrays suitably scaled down in size may be useful for pulsed-field sequencing.

4 Ill.

Electronic Resource