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Biomedical subjects

N Davidson

Publications and source records attributed to N Davidson.

At least 253 records · Page 14Linked to original sources
PubMed1980

Baboon endogenous virus genome. I. Restriction enzyme map of the unintegrated DNA genome of a primate retrovirus.

A detailed restriction map was deduced for the genome of an endogenous retrovirus of a higher primate, that of baboon. The cleavage sites for 12 restriction enzymes were mapped. The unintegrated linear viral DNA intermediate that is produced by infection of permissive cells with baboon endogenous virus was isolated. Hybridization with a strong-stop complementary DNA probe demonstrated presence of a terminal repetition in the linear viral DNA. The positions of restriction sites for two particular enzymes, SmaI and XhoI, near each end were consistent with this result and indicated that the length of the repetition is 0.55 +/- 0.01 kilobase. The linear viral DNA had a unique restriction map indicating that it is not a set of random circular permutations of the RNA genome. From hybridization with a 3'-specific probe, the DNA restriction map was aligned relative to the 5'-to-3' orientation of the viral RNA. We observed a minor heterogeneity in a BamHI recognition site 1.95 kilobases from the right end of the linear map.

Animals↗
PubMed1979

Is it time that the kings of London lost their empires?

It is rumoured that Patrick Jenkin is mulling over a reorganisation of the health service in London which could strip it of its traditional predominance in medical matters. Nick Davidson looks at some of the arguments for and against. Administrators in the home counties feel that they don't carry the same clout as regional officers who, they argue, do not understand problems facing rural areas. The home countries are fed up with being in regional authorities where the votes are stacked against them.

Catchment Area, Health↗
PubMed1979

Localization and characterization of transport-related elements in the plasma membrane of turtle bladder epithelial cells.

A mixed membrane preparation obtained from turtle bladder epithelial cells contains (Na+ + K+)-ATPase, adenylate cyclase and protein kinase, which interact with ouabain, norepinephrine and cyclic AMP, respectively. When such a preparation is obtained from bladders which had been preexposed to serosal fluids containing the tritiated form of 4,4'-diisothiocyano-2,2'-disulfonic stilbene, the subsequently isolated membrane proteins are enriched in tritium as well as in the afore-mentioned enzymes, none of which is inhibited. Free-flow electrophoresis separates the mixed membrane preparation into two distinguishable groups: one, construed as apical membranes, is enriched in norepinephrine-sensitive adenylate cyclase and cyclic AMP-sensitive protein kinase; the other, construed as basal-lateral membranes, is enriched in ouabain-sensitive ATPase and 4,4'-diisothiocyano-2,2'-disulfonic stilbene-binding proteins. The physiological counterparts of these enzymatically defined membrane markers are the mucosal sidedness of the transport effects of norepinephrine and cyclic AMP derivatives and the serosal sidedness of the transport effects of ouabain and disulfonic stilbenes in the intact turtle bladder. The discreteness and ion selectivity of each membrane-bound, transport-related element are discussed in relation to the corresponding characteristics of each transport process in vivo; the possibility of regulation of anion transport by adenylate cyclase-protein kinase system is also discussed.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
PubMed1979

Electron microscopic mapping of proteins bound to herpes simplex virus DNA.

Exonuclease digestion experiments have suggested that there is a protein(s) bound close to one or both ends of herpes simplex virus-1 (HSV) DNA. The existence of such bound proteins has been positively demonstrated and their positions on the HSV genome determined by application of a newly developed method for electron microscopic mapping of proteins bound to nucleic acids. Purified HSV DNA was treated with dinitrofluorobenzene under conditions that covalently attach the dinitrophenyl (DNP) group to the proteins in a protein-nucleic acid complex. The HSV DNA-protein-(DNP)n complex was treated with rabbit anti-DNP IgG, and, in some cases, additionally treated with monovalent Fab fragments of goat anti-rabbit IgG, and mounted for examination in the electron microscope. Electron opaque dots representing the protein-(DNP)n-(IgG)m complex were seen on the HSV DNA. Direct measurements of the positions of the protein, as well as partial denaturation mapping, indicate that there are four positions for protein bound to HSV DNA: two near but not at the two ends and two at sites corresponding to the internal inverted repeats of the ends. These results suggest that there is a specific protein binding sequence within the direct terminal repeat of HSV DNA. The previous observation that HSV DNA is more sensitive to digestion by a 3' than by a 5' exonuclease then indicates that the bound protein(s) is more intimately associated with one strand of the specific sequence than with the complementary strand.

Binding Sites↗
PubMed1979

Time to look at rules which govern a monopoly game.

What we buy and who we buy it from are basic questions posing growing complexities for the supply service. Do we buy the right things? What about the demand for a central supply council? How alert are we to an expanding monopoly in a contracting industry? The debate in the wake of the Salmon report goes on unabated. Author supplies it with more ammunition on the eve of the supply officers' conference in Nottingham.

Capital Expenditures↗
PubMed1979

Improved methods for the formation and stabilization of R-loops.

Improved methods for the formation and stabilization of R-loops for visualization in the electron microscope are presented. The two complementary strands of a duplex DNA are photochemically crosslinked once every 1 to 3 kb using 4, 5', 8 trimethylpsoralen. R-loops are then formed by incubation with RNA in 70% formamide at a temperature above the DNA melting temperature. Finally, the R-loops are stabilized by modifying the free single strand of DNA with glyoxal, thus minimizing the displacement of the hybridized RNA by branch migration. In this manner R-loops can be formed and visualized at a high frequency irrespective of the base composition of the nucleic acid of interest.

Base Sequence↗
PubMed1979

Opening doors to meet the neeeds of the people served.

Does the patient have an effective say in health service decisions that directly affect him? Community health councils have been with us since 1974 but how representative are they and how much influence can they exert on health authorities? Concluding our series on the Royal Commission, author examines these questions and outlines the views of patient organisations and health administrators on the proposal for electing rather than appointing members to AHAs.

Community Participation↗
PubMed1979

Health administration: no room for revolt at the top.

The 'revolt' by members of Lambeth, Southwark and Lewisham AHA(T), as well as the dilemmas posed by the Normansfield report, have recently done more than anything to disturb the calm of the RHAs. Author investigates what officers at the regional tier expect and hope of the Royal Commission in the aftermath.

Administrative Personnel↗
PubMed1979

A possible neuronal release of [14C] GABA from the rat cerebellum in vivo.

Release patterns for exogenously applied [14C] labelled alpha-amino-n-butyric-acid (GABA) have been investigated in rat cerebellar cortex in vivo. An increase in [14C] GABA release could be evoked by stimulating with high (40 mM) K+ or veratridine (10(-4)M) but not with direct electrical stimulation. Biphasic patterns for high K+ and possibly veratridine stimulated release of GABA suggest the existence of two separate anatomical sources of isotope which are sensitive to these depolarising stimuli. Both K+ and veratridine-evoked GABA release are calcium dependent. Studies involving partial replacement of Na+ with HEPES, (N-2-hydroxyethyl-piperazine-N-2-ethane-sulphonic acid), sucrose or choline chloride also reveal a sodium dependency of [14C] GABA release. These studies collectively indicate a neuronal source for evoked GABA release, a criterion for transmitter identification not previously satisfied in the cerebellar cortex.

Animals↗
PubMed1979

Prejudice that faces women as managers.

Women now outnumber men in health service administrative training schemes but many will leave to have families. Unless the service can find ways of attracting them back it will face an unprecedented staff crisis at the top.

Administrative Personnel↗