Factors in the Testing and Application of Algicides

A review is presented of some of the factors affecting the laboratory testing and practical applications of chemicals toxic to algae. The basic factor demonstrated is that the amount of chemical required to inhibit the growth of algae is dependent on the amount of algae present and not on the volume of water in which the algae are dispersed. It is shown how a chemical can be tested for algistatic or algicidal properties, thus enabling one to decide how best to apply a particular chemical. The selectivity of chemicals and the development of resistance in algae towards certain chemicals is demonstrated. Also, it is shown how certain algae can appear to be resistant to chemical treatments because of their growth habit or their production of extracellular products which affect the toxicity of added chemicals. With a better understanding of how various factors can influence the effectiveness of toxic chemicals, it is hoped that the selection of a chemical and method of application to a particular problem will be more successful.     

Myasthenia Gravis: Anesthetic and Surgical Management of the Patient Undergoing Thymectomy

Experience in the anesthetic and surgical management of 25 patients with myasthenia gravis is recorded. These are subdivided into two groups: those operated on during the period 1950-1958 and those operated on during the period 1959-1964. The purpose of this paper is to indicate improvement in mortality and morbidity due to three major advances: (1) use of the decamethonium diagnostic test in a myasthenia gravis clinic; (2) improvements in assessment and management of respiratory insufficiency; and (3) avoidance of anticholinesterase treatment in the immediate and early postoperative recovery period.Fourteen patients with myasthenia gravis, including five with thymoma and two who were refractory to medication, were in the second (1959-1964) group. There were no deaths and no myasthenic or cholinergic crises. Three prophylactic tracheostomies were performed. No emergency bronchoscopies or tracheostomies were required.     

Effect of Desipramine on a Glycoprotein Sialyltransferase Activity in C6 Cultured Glioma Cells

The tricyclic antidepressant desipramine, when added to culture medium, gave rise in C6 rat glioma cells to a decrease of the activity of the enzyme asialofetuin sialyltransferase. The inhibition was dose and time dependent and was observed in both multiplying cells and cells blocked with 2 mM thymidine or depletion of amino acids. This inhibition was rather specific to the sialyltransferase, as under the conditions where this enzyme was inhibited up to 70%, other enzymes such as dolichol phosphate mannose synthetase, glutamine synthetase, and glycerol phosphate dehydrogenase remained unaffected. This inhibition was not reversed after removal of desipramine from the medium and was not observed by direct addition of desipramine to the sialyltransferase incubation assay. Under the same conditions, W-7 [N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide], which is known to be a potent calmodulin antagonist and an inhibitor of calmodulin-dependent kinases, gave the same concentration-dependent inhibition profile of sialyltransferase as desipramine, whereas H-7 [1-(5-isoquinolinylsulfonyl)-2-methylpiperazine], which is an inhibitor of protein kinase C and cyclic nucleotide-dependent kinases, had no effect. So, it is suggested that desipramine inhibits the sialyltransferase activity in C6 glioma cells through a calmodulin-dependent system.     

Efficacy and stability of wettable powder amitraz in field and laboratory studies against Boophilus annulatus (Acari: Ixodidae) in south Texas

A study was done at the USDA-ARS, Cattle Fever Tick Research Laboratory, Mission, Tex., to determine the efficacy of a 50% wettable powder (WP) amitraz formulation applied as a whole-body spray in a standard dip vat, and in a laboratory bioassay against Boophilus annulatus (Say) on cattle. A study also was done at the King Ranch in Kleberg County, Tex., to determine the stability of 50% WP amitraz in a dip vat under South Texas conditions Cattle were infested with all parasitic life stages of B. annulatus and were sprayed or dipped with a concentration of 0.025% amitraz. As determined by calculations of the index of reproduction, the whole-body spray treatment provided 86% control of the ticks and the dip treatment provided 99.8% control. Laboratory bioassay results compared favorably with those obtained with the dip vat treatment. Amitraz WP settled very rapidly in the freshly charged ranch vat. However, as more cattle were dipped and the vat became polluted with dirt and excrement, settling occurred much more slowly. Overall, amitraz remained stable in the vat during the test period.     

The new politics of exclusion: Antecedents to the rebellion in Mexico

Thatcherism's search for the enemies within; its operations across the different lines of division and identification in social life...its rooting of itself inside a particularly narrow, ethnocentric and exclusivist conception of national identity; and its constant attempts to expel symbolically one sector of society after another from the imaginary community of the nation-these are as central to Thatcherism's hegemonic project as the privatization programme or the assault on local democracy...     

Attenuation of visible light by phytoplankton in a vertically structured ocean: solutions and applications

To find the solution to problems in applied marine optics, wedo not always need to compute the submarine irradiance at alldepths; in many cases, it is sufficient to know the averageattenuation of light for finite layers of arbitrary thickness.If multiple scattering can be neglected, the average attenuationof light in a finite layer of the water column depends onlyon the vertical distribution of the attenuating substances;in open-ocean waters, the most important of these is phytoplankton.It is shown how the average attenuation of monochromatic lightin an arbitrary layer can be determined when the vertical pigmentprofile takes one of two standardized forms: a shifted Gaussianor a triangle. The choice of efficient algorithms to computethe attenuation in a layer using these models is discussed.The extension to polychromatic light involves the selectionof a function to represent the spectral distribution of thespecific absorption coefficient for phytoplankton, as determinedby observation. Chebyshev polynomial representation is shownto be convenient for applications which require the calculationof a weighted wavelength integral. An efficient procedure forthe evaluation of these integrals, Gauss-Chebyshev quadrature,is presented and evaluated. The extension to the computationof bulk properties for discrete layers is straightforward.     

Elemental microanalysis of fibroblasts by a scanning proton microprobe and application to Menkes’ disease

A scanning proton microprobe has been used for the elemental microanalysis of individual fibroblast cells. Both normal fibroblasts and fibroblasts cultured from patients with Menkes' disease, an X-linked genetic disorder known to be associated with defective copper metabolism, were examined by the probe. The cells were cultured on a thin ultra-clean nylon foil and retained on that surface for analysis. The focused high-energy proton beam was used to irradiate selected individual cells and elemental information was derived from X-ray and backscattered proton data. The sensitivity of the scanning proton microprobe to trace concentrations of heavy elements has allowed this elemental information to be used to identify individual cells as being either normal or a Menkes' mutant. The cell identification was based on the application of discriminate analysis to a data set formed from the ratios of copper to each of the macroelements present in the cell. This method of cell identification offers the promise of rapid diagnosis of Menkes' disease.     

Characterisation of a 5-bp deletion in exon 4 of the factor VIII gene: concordance with slipped-mispairing at DNA replication

In an attempt to characterize disease producing mutations in the factor VIII gene we screened exons 4, 7, 8, 11, 12 and 16 by PCR-SSCP (polymerase chain reactionsingle strand conformation polymorphism), in 12 randomly selected haemophilia A patients. These exons were chosen because they have been reported to harbour a disproportionately high number of mutations relative to their size. Using this strategy we detected a frame-shifting 5-bp deletion (TACCT, involving nucleotides 519–523), which is predicted to result in a severely truncated factor VIII polypeptide, terminating approximately midway through the conserved A1 domain and resulting in the observed severe phenotype. We also showed that the sequence in the vicinity of the observed deletion is concordant with the modified slipped-mispairing at DNA replication model of Krawczak and Cooper.