Search Results - (Author, Cooperation:R. Wyatt)

2011-11-25

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

AIDS Vaccines/chemistry/immunology ; Amino Acid Motifs ; Amino Acid Sequence ; Antibodies, Neutralizing/chemistry/*immunology ; Antibody Affinity/immunology ; Antibody Specificity/*immunology ; Antigen-Antibody Complex/chemistry/immunology ; Binding Sites, Antibody/immunology ; Conserved Sequence ; Crystallography, X-Ray ; Epitopes/chemistry/immunology ; Glycopeptides/chemistry/immunology ; Glycosylation ; HIV Antibodies/chemistry/*immunology ; HIV Envelope Protein gp120/*chemistry/*immunology ; HIV-1/*chemistry/*immunology ; Hydrogen Bonding ; Immune Evasion ; Models, Molecular ; Molecular Sequence Data ; Polysaccharides/chemistry/immunology ; Protein Structure, Quaternary ; Protein Structure, Tertiary

2018-02-14

The American Society for Microbiology (ASM)

0022-538X

1098-5514

Medicine

2012-11-16

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Amino Acid Substitution ; Antibodies, Neutralizing/chemistry/*metabolism ; Antibody Specificity ; Cells, Cultured ; HEK293 Cells ; HIV Antibodies/chemistry/isolation & purification/*metabolism ; HIV Envelope Protein gp41/chemistry/*immunology ; HIV-1/*physiology ; Humans ; Models, Molecular ; Molecular Sequence Data ; Protein Binding ; Protein Structure, Tertiary

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Mass-fragmentographic methods are described that enable the simultaneous measurement of total, free, and conjugated catecholamines in brain tissues. These methods were used to assess the distribution, kinetics, and pharmacological characteristics of total, free, and conjugated catecholamines in the hypothalamus, caudate nucleus, hippocampus, and septum. Conjugated norepi-nephrine (NE) represents ˜20% of total NE in the hypothalamus, septum, and hippocampus, whereas the percentage is ˜ 50% in the caudate nucleus. The percentages of conjugated dopamine (DA) in these brain areas are consistently less than those of NE (˜13%). Although in the hypothalamus the steady-state concentrations of total, free, and conjugated NE are over four times higher than those of the corresponding total, free, and conjugated DA, the turnover rates of this DA are comparable with those of the corresponding NE. Further, the ratios of conjugated NE or DA turnover rates to those of the total amines are higher than the corresponding ratios of their steady-state concentrations. Treatments with pargyline (75 mg/kg, i.p.; rats killed 30 and 60 min later) failed to change the contents of conjugated catecholamines in the hypothalamus and the caudate nucleus significantly. Pharmacological manipulation with a number of proto-typic drugs revealed that although the assay of conjugated catecholamines might shed additional light on the effects of drugs on central catecholamines, the assessment of total or free amines are on the whole equally informative. In conclusion, a detailed assessment of brain conjugated catecholamines is reported. The information provided, fills a gap in our knowledge that has up to now not been adequately addressed.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract— Vanillylmandelic acid (VMA) and 3-methoxy-4- hydroxyphenylglycol (MHPG) were measured in rat brain by a mass fragmentographic procedure. The concentration of VMA and MHPG in whole brain is 11 and 533 pmol/g, respectively. Both compounds were found in all areas of brain studied with VMA, as a percentage of both metabolites, ranging between about 1 and 8%. From the decline of the compounds after pargyline. 75 mg/kg i.p., we calculated that the rate of formation of VMA is 15 and for MHPG 202 pmol/g per h. The fractional rate of elimination of VMA and MHPG is 1.4 and 0.38 h−1, respectively. The rapid rate of loss of VMA suggests that it is transported from brain. However, we were unable to block the elimination of VMA from brain by treatment with probenecid. In contrast, the elimination of MHPG could be blocked by treatment with probenecid. Our study adds support to the notion that MHPG is a major whereas VMA is a minor product of norepinephrine metabolism in brain.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

—A mass fragmentographic procedure is described for the simultaneous quantification of a number of deaminated metabolites derived from tyramine, octopamine, dopamine, and norepinephrine. With this method, several of the metabolites were measured in normal rat brain. The results support the central nervous system origin of tyramine, octopamine and their metabolites. The concentration of the dopamine metabolite, homovanillic acid, in the rat brain was found to be about 15% higher than that of dihydroxyphenylacetic acid. As for the metabolites of norepinephrine, vanilmandelic acid concentration was found to be about 5% that of 3-methoxy-4-hydroxyphenylglycol. The possible role of vanilmandelic acid in the CNS metabolism of norephrine is discussed.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

—A mass fragmentographic method for the assay of phenylethylamine (PEA) and a number of related amines in several biological materials is described. The gas chromatographic column employed for this analysis is a 12ft 1/8 in. o.d. steel column packed with 0.5% OV22+ 2% SE54 + 1% OV210 coated on 80/100 mesh chromosorb W (HP). The mass spectral characteristics of these amines are illustrated, compared, and discussed.Of the various monoamines which could be measured, only PEA, m- and p-tyramine were detected in measurable quantities. Phenylethanolamine and p-octopamine were found in trace amounts in urine, plasma, cerebrosponal fluid, and rat brain. No diurnal variation in the urinary excretion of PEA, m- and p-tyramine was observed. Plasma concentration of PEA or p-tyramine did not significantly change 1 h after eating a breakfast. Furthermore, consuming 200 g of Cadbury milk chocolate containing about 1 mg of PEA, 0.1 mg of phenylethanolamine and 10 mg of p-tyramine did not significantly alter urine excretions of these three amines.In the brain, as has been reported by others, we found that PEA and p-tyramine are not evenly distributed and that the highest concentrations are found in the hypothalamus and caudate.From the results obtained we concluded that PEA, m- and p-tyramine are probably produced from endogenous sources and that the direct contribution of diet to their urine excretion is small.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

A detailed comparison of quasiclassical trajectory (QCT) and quantum mechanical (QM) reaction probabilities and differential cross sections for the H+D2→HD+D reaction at the collision energies of 0.54 and 1.29 eV has been carried out using the same potential energy surface. The theoretical simulation of the recently published experimental results is also reported. The comparisons made here demonstrate the level of agreement between QCT and QM approaches, as well as between theory and experiment for this reaction.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Critical care services appear to face increasing demand. To attempt to identify factors which may predispose to such increases in demand, the patients and their treatment were reviewed. The patients' ages, referring specialty and their risk of hospital mortality were recorded on admission. The durations of respiratory and renal support (if required) were recorded. Pulmonary artery catheter insertion and the number of vasoactive drugs infused were also noted. During the study, the capacity of the intensive care unit was initially increased by one bed (from six to seven) and later by a six-bedded high-dependency unit. This capacity increase was not matched by a proportionate decrease in occupancy. The patients' mean ages increased by 1 year per year. The number of patients referred from general surgery consistently increased. The proportion of patients receiving vasoactive drugs and pulmonary artery catheters declined as did the duration of respiratory and renal support.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

The collinear dynamics of a model diatom–diatom system is investigated. The collision partners are harmonic oscillators for which the masses and force constants are chosen to correspond to those of the nitrogen and oxygen molecules. The interaction between the molecules arises from a Lennard-Jones 6-12 potential acting between the inside atoms in the collinear system. Quantum mechanical close coupled calculations are performed for several collision energies ranging from 1.0 to 2.25 eV. The state-to-state transition probabilities which are extracted from these calculations are then used as a benchmark for comparison. Semiclassical calculations are performed within the framework of a classical path approximation. A simple scheme to modify the classical path to reflect energy exchange between the collision coordinate and the internal degrees of freedom is found to improve the results. On the whole, the agreement between the semiclassical and the quantum mechanical results is surprisingly good. The classical trajectory calculations correctly display many of the qualitative features of the collisions but the numerical agreement is not as close. Unexpectedly, the classical results do not appear to be improving as the collision energy is increased.

Electronic Resource

1095-8649

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Investigations into the biology of the roach and the pathogenic tapeworm Ligula intestinalis (L.) populations at Slapton Ley, Devon were carried out between October 1982 and December 1984. Data collected from the lake since 1977 have also been re-analysed to determine how the dramatic improvement in the individual growth rate of the roach over this period may have affected the growth, maturation and life-cycle of Ligula. Only the very young roach at this site become infected, so it was possible to follow cohorts of plerocercoids of similar age through each roach year class. Results for the 1978 and 1983 year classes are presented in detail. The roach grew extremely rapidly from May to August in each year, resulting in a pronounced cyclical pattern of changes in the condition of the roach, with the lowest condition occurring in late winter and spring. The yearly increase in the roach growth rate was accompanied by an increase in plerocercoid growth rate in the 0 + roach, but not in the 1 + roach. The growth rate of the plerocercoids was very high compared to that at other sites. It is usual for the parasite index (PI) of Ligula-infected fish to be high and to increase throughout their first few years of life. At Slapton, however, a lack of multiple infections has prevented high PIs from occurring, and in recent years the growth rate of the roach has been so high that the plerocercoids were unable to maintain a high weight relative to the fish, and the highest PIs occurred in the 0 + roach throughout late winter and spring. In recent year classes, therefore, the maximum PIs and highest pathogenicities coincided with the period of lowest condition in the 0+ roach. Observations of both caged and natural populations of 0+ roach over winter showed that a significant loss of roach containing the larger plerocercoids occurred from the population. In vitro cultivation of Ligula plerocercoids showed that they were capable of maturation at weights of 0.5 g, and only 6 months after having infected the roach. The increase of the growth rate of the plerocercoids in the 0+ roach has therefore resulted in a greater proportion of these plerocercoids being capable of infecting the definitive host. As a result of the increase in individual growth rate of the roach at Slapton, the potential for Ligula transmission, as measured in terms of both their pathogenicity and maturity, has shifted from the 1 + to the 0+ roach.

Electronic Resource

1095-8649

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Investigations into the biology of the roach population at Slapton Ley, Devon, U.K. were carried out between October 1982 and December 1984 and data collected from the lake since 1977 have been re-analysed to assist interpretation. The roach population has been characterized in recent years by extreme year class variation and a tendency for year classes to alternate in strength. The survival of the roach was very poor, and the spawning population therefore consisted largely of 2-and some 3-year-old fish. Consequently, the size of the spawning stock was small and dependent on the strengths of the year classes that it contained. Recruitment to many year classes was probably limited by the size of the spawning stock. The occurrence of a poor year class in the population would therefore set up an autonomous cycle of poor recruitment to alternate year classes in a manner similar to many tropical marine fisheries. Observation of other British roach populations showed that a short life-span may be associated with conditions that promote very rapid growth rates. The growth rate of individual roach at Slapton was found to be one of the fastest in Britain, and this was apparently due to the very high productivity of Slapton Ley together with the persistence of the roach population at very low densities.

Electronic Resource