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Biomedical subjects

B J Smith

Publications and source records attributed to B J Smith.

At least 253 records · Page 14Linked to original sources
PubMed1981

Conformation studies of histone H1(0) in comparison with histones H1 and H5.

The class of lysine-rich histones, H1, found in most eukaryotic cells is largely replaced by another class of lysine-rich histones, H5, in avian and other erythrocytes. Erythrocytes are transcriptionally inert and this state has been attributed to the presence of H5. Although there are many sequence differences between H1 and H5 both molecules have very similar structures with three well-defined domains: a flexible basic N-terminal region, an apolar globular central region and a flexible basic C-terminal region. The lengths of the N-terminal regions are different for H1 and H5 whereas the lengths of the central and C-terminal regions are very similar. Considerable interest attaches to the findings that another type of mammalian lysine-rich histone H1(0) has an apolar region exhibiting considerable sequence homology (70%) with the central globular region of H5. The abundance of H1 in cells has been found to correlate inversely with their mitotic activities. Conformational studies using high-resolution nuclear magnetic resonance and optical spectroscopy have been made of H1 and its conformational behaviour has been compared with those of H1 and H5. H1 has been found to contain a central globular region of similar size to those found in H1 and H5. However, the conformation and stability of the globular domain of H1 are very similar to the globular region of H5 rather than H1. H1 appears to be a hybrid containing a major feature of the H5 histone. The globular regions of H1 and H5 are known to bind to a specific site on the nucleosome sealing off two turns of DNA. It is proposed that H1 binds to the same site.

Amino Acid Sequence↗
PubMed1981

Paget's disease of bone with particular reference to dentistry.

Paget's disease of bone (osteitis deformans) is a relatively common disorder of uncertain aetiology. It is characterised by abnormal resorption and apposition of osseous tissue in one or more bones of the skeleton. This is a review of Paget's disease with particular reference to dentistry. The prevalence, aetiology, clinical features, radiography, histopathology, biochemistry, oral and dental manifestations, complications and treatment are discussed. One hundred and fifty-two reported cases of Paget's disease of the jaws have been analysed. The upper jaw was more frequently involved than the lower jaw in the ratio of more than 2:1. This survey shows a higher prevalence of Paget's disease in the mandible than previously recorded.

Adult↗
PubMed1980

Histone H1o: its location in chromatin.

Histone H1o is an H5-like protein found in mammals. Its location in chromatin from animal tissues has been studied by micrococcal nuclease digestion and by quantitation. It was found that H1o occurs in the linker region of chromatin, and replaces H1 there as it does so. As much as a third of the H1 becomes replaced, at least in some tissues. The abundance of H1o was similar in bulk chromatin and in a mononucleosome population which was putatively enriched in transcribed DNA sequences. It was concluded that H1o probably does not suppress transcription.

Animals↗
PubMed1979

The binding of an avian myeloblastosis virus basic 12,000 dalton protein to nucleic acids.

The binding of a basic 12,000 dalton protein (p12) from avian myeloblastosis virus to viral RNA and heterologous DNA has been investigated. The binding stoichiometries and constants were determined by an extrinsic fluorescence assay. In both cases each bound p12 molecule occupies four nucleotides and the apparent binding constant is approximately 1 x 10(6) M-1. Binding is non-cooperative and there is no apparent difference in the interaction of p12 with viral RNA or heterologous single-strand DNA. The relative binding constant at various ionic strengths was assayed by the nitrocellulose filter procedure. Analysis of the data revealed that each bound p12 molecule forms three ion pairs with the nucleic acid.

Animals↗
PubMed1979

Esthetic factors in removable partial prosthodontics.

For the patient, the appearance of the finished restoration is of paramount importance. To avoid an esthetic failure, the dentist should pay attention to those various components of removable partial dentures which play a role in esthetics.

Acrylic Resins↗
PubMed1977

Alkylation of cytosine and 5-hydroxymethyl-cytosine by methyl methanesulphonate and N-methyl-N-nitrosourea: its relevance to mutagenesis.

The reaction of cytosine and 5-hydroxymethyl-cytosine (OHMeCyt) with a variety of monofunctional alkylating agents has been investigated to evaluate further the possible role of cytosine alkylation in mutagenesis and the possibility that the immunity of T-even phages to mutation by methyl methanesulphonate (MMS) was due to the unreactivity of OHMeCyt towards this agent. Both cytosine and OHMeCyt reacted equally well with the methylating agents MMS and N-methyl-N-nitrosourea (MNU) affording 6% and less than 1% respectively of the 3-substituted derivative. No product was isolated following subjection of the bases to reaction with ethyl methane-sulphonate (EMS), N-ethyl-N-nitrosourea (ENU) or iso-propyl methane-sulphonate (iPMS).

Binding Sites↗