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H Gould

Publications and source records attributed to H Gould.

At least 55 records · Page 3Linked to original sources
PubMed1985

Detection of a unique human V kappa IV germline gene by a cloned cDNA probe.

We have cloned the cDNA encoding the KIV chain of a human antibody with specificity against the major carbohydrate antigen of Streptococcus A. The cDNA has been used as a genetic probe to estimate the number of germline VKIV genes in human DNA. The presence of unique hybridizing bands on digestion of human DNA with several restriction endonucleases and the equivalence of the DNA in a band to a single gene per haploid genome point to the conclusion that there is a unique human VKIV germline gene. The corollary of this conclusion is that the diversity of human VKIV chains must be exclusively due to somatic mutation. This is supported by examination of the sequences of human KIV chain genes and their KIV chain products. Fusion of the unique germline VKIV gene (1) with one of several JK segments, followed by somatic mutations in the V region of the rearranged KIV gene, can account for the known sequences. The restricted germline gene repertoire may account for the small proportion of human KIV chains in the human K chain sequence library (2).

Amino Acid Sequence↗
PubMed1984

Control of RNA polymerase binding to chromatin by variations in linker histone composition.

We have measured the frequency of initiation sites in chromatin for RNA polymerase in vitro as a function of the composition of linker histones (H1 and its analogues). In linker histone-depleted chromatin, RNA chain initiation appears to be restricted to the exposed linker DNA. On titration with purified linker histones, initiation is further restricted to an extent determined by the amount and type of linker histone, and the source of depleted chromatin. The extent of repression is correlated with the capacity of linker histones to induce the formation of higher-order structure in the complex. The results suggest that the effects of linker histones are mediated through the higher-order structure of chromatin, which prevents access of polymerase to the linker DNA. Accordingly, we find that structures imposed by the linker histones after polymerase binding are not inhibitory. Microscopy reveals that the higher-order structure in partially condensed chromatin is discontinuous, with solenoidal units spaced by sections of unravelled nucleosomes. Since salt stimulation of linker histone exchange does not result in derepression of linkers in our assay, we conclude that the distribution of higher-order units in chromatin is static and that the linker histones exchange between high-affinity sites in established units. We have previously shown that the globin gene is selectively unfolded in tissues that express the gene. The present results suggest that the transcriptional activity of specific genes is maintained by differential linker histone binding within chromatin.

Animals↗
PubMed1984

Avoidance of artifacts on computerized tomograms by selection of appropriate surgical clips.

Surgical clips (metallic or plastic) are frequently used for hemostasis and tumor marking. This study evaluated the radiographic and computerized tomographic appearance of different clips and their relative interference with computerized tomographic scans. Metallic clips (stainless steel, tantalum, and titanium) can all be seen on plain radiographs. Tantalum clips caused extensive distortion on computerized tomographic scans which would interfere with scan interpretation. Both stainless steel and titanium clips resulted in much less artifact and interference on computerized tomographic scans. Recent studies have suggested that there may be some risk of torsion of stainless steel clips in nuclear magnetic resonance scanners resulting in tissue damage. Absorbable plastic clips cannot be seen on plain film but are visualized on computerized tomographic scans and do not appear to cause scan artifact. Overall, we recommend the use of either titanium hemostatic clips when tumor marking on plain film is required or plastic clips when tumor marking is less important.

Evaluation Studies as Topic↗
PubMed1984

Properties of a human immunoglobulin epsilon-chain fragment synthesized in Escherichia coli.

A fragment of the cloned gene for the human myeloma ND epsilon chain, coding for the second, third, and fourth domains of the immunoglobulin, has been coupled to the tryptophan control region of an expression plasmid and subcloned in Escherichia coli. Induction of gene expression results in the synthesis of the expected, antigenically active polypeptide of Mr 40,000, which constitutes 18% of total bacterial protein and yields 55 mg/liter of culture. The immunoglobulin, which is aggregated and packed into large inclusion bodies within the bacterial cell, can be dissolved by denaturing solvents and purified by affinity chromatography using anti-IgE Sepharose. Reduced monomeric chains assemble spontaneously into dimers. On assay to measure the inhibition of binding of 125I-labeled human E myeloma protein to Fc epsilon receptors on cultured human basophils, the cloned gene product exhibited 20% of the activity of the native protein.

Basophils↗
PubMed1984

Higher order structure in a short repeat length chromatin.

Polynucleosomes from calf brain cortical neurone nuclei have an average repeat length of less than 168 base pairs. The ability of this material to adopt higher order structure has been assessed by various physical techniques. Although containing on average less DNA per nucleosome than is required to form a chromatosome, this short repeat length chromatin folded in an H1 dependent manner to a structure with properties similar to those observed for longer repeat length chromatins such as that of chicken erythrocyte (McGhee, J.D., D.C. Rau, E. Charney, and G. Felsenfeld, 1980, Cell, 22:87-96). These observations are discussed in the context of H1 location in the higher order chromatin fiber.

Animals↗
PubMed1982

Participation of core histone "tails" in the stabilization of the chromatin solenoid.

We show here that the solenoid is maintained by the combination of linker histones and the nonglobular, highly basic "tails" of the core histones, which play only a minor part in the formation of the nucleosome core (Whitlock and Simpson, 1977. J. Biol. Chem. 252:6,516--6,520; Lilley and Tatchell, 1977. Nucleic Acids Res. 4:2,039--2,055; and Whitlock and Stein, 1978. J. Biol. Chem. 253:3,857--3,861). Polynucleosomes that contain core histones devoid of tails remain substantially unfolded under conditions otherwise favorable for the formation of solenoids. The tails can be replaced by extraneous basic polypeptides and in the presence of the linker histones the solenoid structure is then spontaneously recovered, as judged by a wide variety of structural criteria. The inference is that the core histone tail segments function by providing electrostatic shielding of the DNA charge and at the same time bridging adjacent nucleosomes in the solenoid. Our results carry the further implication that posttranscriptional modifications, such as acetylation of epsilon-amino groups, that reduce the positive charge of the core histone tails will tend to destabilize the higher-order structure and could thus render the DNA with which they are associated more readily available for transcription.

Centrifugation, Density Gradient↗
PubMed1981

How should we talk about acute leukaemia to adult patients and their families?

Problems of communication with patients with acute leukaemia and their families were explored by interviewing the next of kin of 26 patients, six of whom were still alive. In all but two cases the diagnosis had been disclosed to the relatives before the patient, but almost one-third of the relatives were not entirely satisfied with the way in which the diagnosis was presented. Medical prognostications at these initial interviews were, on the whole, regarded as being realistic by the relatives. Nine patients learnt of their diagnosis at an early stage, but relatives were undecided whether patients should be told of the diagnosis in explicit terms. Patients often established complete dependence on the hospital and its staff and had difficulties in relating to their own general practitioners while at home during their illness. Social chats were preferred by the relatives rather than regular progress reports from the doctors.

Acute Disease↗
PubMed1981

Regulation of the higher-order structure of chromatin by histones H1 and H5.

Chicken erythrocyte chromatins containing a single species of linker histone, H1 or H5, have been prepared, using reassembly techniques developed previously. The reconstituted complexes possess the conformation of native chicken erythrocyte chromatin, as judged by chemical and structural criteria; saturation is reached when two molecules of linker histone are bound per nucleosome, as in native erythrocyte chromatin, which the resulting material resembles in its appearance in the electron microscope and quantitatively in its linear condensation factor relative to free DNA. The periodicity of micrococcal nuclease-sensitive sites in the linker regions associated with histone H1 or H5 is 10.4 base pairs, suggesting that the spatial organization of the linker region in the higher-order structure of chromatin is similar to that in isolated nucleosomes. The susceptible sites are cut at differing frequencies, as previously found for the nucleosome cores, leading to a characteristic distribution of intensities in the digests. The scission frequency of sites in the linker DNA depends additionally on the identity of the linker histone, suggesting that the higher-order structure is subject to secondary modulation by the associated histones.

Animals↗
PubMed1980

Reversible dissociation of linker histone from chromatin with preservation of internucleosomal repeat.

Procedures are described for the dissociation of histones H1 and H5 from chicken reticulocyte chromatin without disruption of the native core histone-DNA complex. The comparative properties of native and depleted chromatin with respect to sedimentation, thermal denaturation, and sensitivity to nuclease digestion have been studied. The changes in these properties resulting from removal of the linker histones are fully reversed when histone H5 is added back to the depleted chromatin.

Animals↗
PubMed1979

Synthesis of carbonic anhydrase in rabbit and chicken reticulocyte lysates.

The synthesis of carbonic anhydrase, the second most abundant soluble protein of red blood cells, is shown to occur in rabbit and chicken reticulocyte lysates. This translation product was identified by chloroform/ethanol extraction, polyacrylamide gel electrophoresis in sodium dodecylsulphate and peptide mapping. In rabbit retic-locyte lysates, predominantly one of the two red cell isozymes, carbonic anhydrase I, is synthesised. The proportion of carbonic anhydrase synthesis (0.2-0.8% of total protein synthesis) in vitro is comparable to that (0.2-1.0%) in vivo for both rabbit and chicken reticulocytes.

Amino Acids↗