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Biomedical subjects

B D Patterson

Publications and source records attributed to B D Patterson.

At least 19 recordsLinked to original sources
PubMed2006

Energetic surface smoothing of complex metal-oxide thin films.

A novel energetic smoothing mechanism in the growth of complex metal-oxide thin films is reported from in situ kinetic studies of pulsed laser deposition of on , using x-ray reflectivity. Below 50% monolayer coverage, prompt insertion of energetic impinging species into small-diameter islands causes them to break up to form daughter islands. This smoothing mechanism therefore inhibits the formation of large-diameter 2D islands and the seeding of 3D growth. Above 50% coverage, islands begin to coalesce and their breakup is thereby suppressed. The energy of the incident flux is instead rechanneled into enhanced surface diffusion, which leads to an increase in the effective surface temperature of DeltaT approximately 500 K. These results have important implications on optimal conditions for nanoscale device fabrication using these materials.

Journal Article↗
PubMed2005

Improved data acquisition in grazing-incidence X-ray scattering experiments using a pixel detector.

The use of an area detector in grazing-incidence X-ray experiments lends many advantages in terms of both speed and reliability. Here a discussion is given of the procedures established using the PILATUS pixel detector developed at the Swiss Light Source for optimizing data acquisition and analysis of surface diffraction data at the Materials Science beamline, especially with regard to reflectivity measurements, crystal truncation and fractional order rods, and grazing-incidence diffraction experiments.

Journal Article↗
PubMed2005

X-ray diffraction method for the investigation of contacts between solid surfaces.

A coherent X-ray scattering method for investigating the formation of the contact region between two solid surfaces is presented. Diffraction of X-rays from two crossed cylindrical quartz surfaces, coated with Cr and TiO(2), revealed a total contact area of 90 +/- 10 microm. In the so-called Hertz model for two surfaces in non-adhesive contact, this value is directly related to the displacement of the surfaces and the applied external force. Values of 40 +/- 3 nm for the displacement and 24 +/- 3 mN for the force are found. The method is also useful for studying liquids in confinement.

Algorithms↗
PubMed2001

Pancreatitis associated with valproic acid: a review of the literature.

Black box warnings for valproic acid caution clinicians of the potential for fatal hepatotoxicity and teratogenicity. Since 1979, case reports of pancreatitis induced by valproic acid have been published in the medical literature. As a result, pancreatitis was added to the black box warnings for valproic acid. We performed searches of MEDLINE and International Pharmaceutical Abstracts and found valproic acid-induced pancreatitis in 45 patients from 31 published articles. Demographics, clinical characteristics, and outcomes of these patients are summarized. Recommendations for monitoring the potential for pancreatitis to develop in patients receiving valproic acid therapy are described, as are potential mechanisms for inducement of pancreatitis by valproic acid.

Amylases↗
PubMed2000

The man-eaters with bad teeth.

Two cases of man-eating lions feeding on large numbers of humans (1898, 1991) are discussed. The forensic dental evidence from the lions' remains and eyewitness reports indicate all three lions had serious dental/oral pathology, which may have contributed to their selection of human food over more challenging natural animal prey.

Animals↗
PubMed1994

An electrophoretic method to detect cold-induced dissociation of proteins in crude extracts of higher plants.

The phenomenon of cold denaturation has been firmly established recently in several proteins. Some multimeric enzymes from plant origins are believed to dissociate under some circumstances in the cold. To determine the presence and number of soluble, non-membrane-bound protein that undergoes cold-induced dissociation in plants, we have devised a special two-dimensional polyacrylamide gel electrophoretic method using two native gradient gels. Examination of the gel run at 0 degrees C in the second dimension showed the presence of four cold-dissociated proteins running below the diagonal and staining intensely with silver, in the extract of maize leaves. The electrophoretic method described here is expected to be a convenient way to detect cold-induced dissociation of soluble proteins in crude extracts of various tissues. It is also possible to estimate roughly the molecular weights of both the cold-dissociated subunit and the native protein from which it is derived.

Cold Temperature↗
PubMed1989

A pilot controlled study of the use of imipramine to reduce myotonia.

It has been hypothesized that myotonic dystrophy is caused by a generalized disorder of membrane aminergic and petidergic receptors. A single uncontrolled study has suggested that the affective symptomatology and muscular disability of this disorder might be improved by tricyclic antidepressant treatment. In the present study, 12 adult patients with myotonic dystrophy (age range 18-55 yr) were treated with imipramine and placebo in a double-blind crossover paradigm. Both grip and percussion myotonia were significantly improved by imipramine treatment independent of change in depressive symptomatology. Serum drug levels revealed nonlinear elimination kinetics for imipramine in this patient population.

Adult↗
PubMed1986

Biochemical diagnosis and management of corticosterone methyl oxidase type II deficiency.

Corticosterone methyl oxidase deficiency type II (CMO type II deficiency) is an autosomal recessive disorder characterized by a defect in the terminal step of aldosterone biosynthesis. Previous reports emphasized the diagnostic utility of elevated urinary ratios of 18-hydroxytetrahydro-compound A to tetrahydro-aldosterone, which are primary metabolites of 18-hydroxycorticosterone (18-OHB) and aldosterone, respectively. Limited data suggest that plasma ratios of 18-OHB to aldosterone are also abnormal in affected individuals. We report serum steroid profiles in two siblings with CMO type II deficiency. Serum levels of aldosterone precursors were elevated in both patients before treatment. In particular, the serum ratios of 18-OHB to aldosterone were greatly elevated and declined to normal levels during mineralocorticoid replacement. The possibility of heterozygote detection using this ratio is suggested. We also confirm previous reports of a detrimental effect on linear growth rate after cessation of mineralocorticoid therapy despite maintenance of normal serum electrolytes. This effect is associated with biochemical evidence of chronic salt depletion. Based on our observations, we recommend that serum 18-OHB to aldosterone ratios be routinely measured for the diagnosis and management of patients with CMO type II deficiency.

Adrenal Cortex Hormones↗
PubMed1985

Uterine tumor resembling an ovarian sex-cord tumor: report of a case of an endometrial stromal tumor with foam cells and ultrastructural evidence of epithelial differentiation.

Uterine tumors resembling ovarian sex-cord tumors are of uncertain histogenesis. We report such a neoplasm in which epithelial features observed by light microscopy were confirmed by electron microscopy and in which foam cells resembling those present in the stroma of hyperplastic endometria and in carcinoma represented a conspicuous intrinsic component. The lesion is interpreted as arising from endometrial stroma or multipotential uterine mesenchyme that has differentiated toward endometrial stroma and epithelium. The relationship of these uterine tumors to ovarian sex-cord stromal tumors and plexiform tumorlets is discussed.

Adult↗
PubMed1984

Estimation of hydrogen peroxide in plant extracts using titanium(IV).

Methods for the estimation of hydrogen peroxide in acetone extracts using titanium(IV) are likely to overestimate hydrogen peroxide when applied to plant leaves. Pigments appear to co-precipitate with the titanium complex and cannot be removed by washing with solvents. Fluoride, which specifically removes the color of the titanium-peroxide complex, removes only some of the color from the reactions with plant extracts. This problem has been avoided by extracting tissues with trichloroacetic acid, and measuring peroxide against catalase-treated blanks by its reaction with the complex of titanium(IV) with 4-(2-pyridylazo) resorcinol. Levels of hydrogen peroxide in leaves of a variety of species were found to range from about 0.1 to 0.6 mumol X g-1.

Catalase↗
PubMed1984

An inhibitor of catalase induced by cold in chilling-sensitive plants.

An inhibitor of catalase accumulated when leaves of chilling-sensitive species were stored in the dark at 0 degrees C. The inhibitor could be removed from crude extracts by passing them through a column of Sephadex G-25. After this treatment, the catalase activity of extracts of chilled tissues was found to be equal to that of extracts from unchilled leaves. When chilled tissues were incubated at 20 degrees C, the inhibitor of catalase was lost, unless the tissues had been irreversibly damaged. It specifically inhibited plant catalase, and had no effect on mammalian catalase, plant malic dehydrogenase, or plant superoxide dismutase.Despite the presence of catalase inhibitor in extracts of chilled plants, no increase in the level of H(2)O(2) in chilled tissues was found, suggesting either that the inhibitor is compartmentalized and not in contact with catalase in vivo, or that the level of H(2)O(2) is controlled by means other than through catalase activity. Plant tissues normally contain H(2)O(2) which is destroyed by catalase when they are damaged. After chilling, H(2)O(2) leaking from already injured cells would not be so readily removed by the inhibited catalase, and could contribute to further injury by acting as a source of free radical oxidants.

Journal Article↗
PubMed1984

Chemical properties, distribution, and physiology of plant and algal carbonic anhydrases.

Plant carbonic anhydrases (CAs) have a range of molecular weights (MW). Among flowering plants, dicotyledons with C3 photosynthesis have two isoenzymes of 140-250K each with 6 subunits, while monocotyledons have two isoenzymes of 42-45K. Plant and animal CAs have a similar amino acid content, subunit size and zinc content, suggesting they are homologous proteins, although the higher plant CAs have no esterase activity and are not strongly inhibited by sulfonamides. Algal CAs vary widely in MW and some are highly sensitive to sulfonamides like the animal enzymes. The two plant isoenzymes, from the chloroplast and cytosol, can be separated by gradient polyacrylamide gel electrophoresis and subsequently visualized by enzymic H+ ion production. In plants, CAs probably facilitate diffusion of CO2 to the site of photosynthetic fixation; they may also have a role in pH regulation, in the use of bicarbonate by aquatic plants and in concentrating inorganic carbon within the chloroplast.

Carbonic Anhydrases↗