Biomedical subjects
D Stone
Publications and source records attributed to D Stone.
The amino acid sequence of dihydrofolate reductase from the mouse lymphoma L1210.
The determination of the amino acid sequence of the dihydrofolate reductase (EC 1.5.1.3) from cells of the mouse lymphoma L1210 is described. The protein was cleaved by cyanogen bromide to produce the six fragments CB1 (residues 1 to 14), CB2 (residues 15 to 52), CB3 (residues 53 to 111), CB4 (residues 115 to 125), CB5 (residues 126 to 139), and CB6 (residues 140 to 186). One of the fragments, CB2, contained an internal homoserine derived from a methionine which was not cleaved by cyanogen bromide. The amino acid sequences and order of the cyanogen bromide fragments were determined by a combination of automatic and manual sequence analyses of the fragments and small peptides from tryptic, thermolytic, and Staphylococcus aureus protease digestions. The complete sequence comprises 186 residues in a single polypeptide chain of molecular weight 21,458. Comparison of the sequence of the L1210 dihydrofolate reductase with the sequences of the enzymes from Streptococcus faecium, escherichia coli RT500, and Lactobacillus casei indicates that all enzymes show some homology, which is strongest in the regions forming the substrate binding cleft.
Comparison of single plane and biplane radionuclide ventriculograms performed in oblique projections in patients with acute myocardial infarction.
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The amino acid sequence of rabbit skeletal alpha-tropomyosin. The NH2-terminal half and complete sequence.
The amino acid sequence of the large cyanogen bromide fragment (residues 11 to 127) derived from the NH2-terminal half of alpha-tropomyosin has been determined. This was achieved by automatic sequence analysis of the whole fragment as well as manual sequencing of fragments derived from tryptic digestion of the maleylated fragment and thermolytic, Myxobacter 495 alpha-lytic and Staphylococcus aureus protease digestion of the unmodified fragment. Methionine-containing overlap peptides have been isolated from tryptic digests of the maleylated protein as well as from S. aureus protease digests of the unmodified protein. Coupled with previously published information on the small cyanogen bromide fragments and methionine sequences of tropomyosin, these analyses have permitted the completion of the primary structure of the protein. The complete sequence differs by only 1 residue (Gln-24 instead of Glu-24) from that previously reported. Analysis of the sequence by several authors has permitted rational explanations for the stabilization of its coiled-coil structure, for the existence of its two chains in a nonstaggered arrangement, for a head-to-tail overlap of molecular ends of 8 to 9 residues, for the existence of 14 actin-binding sites on each tropomyosin molecule, and a suggestion for the site of binding of troponin-T.
Radiosensitization of human erythrocytes by diethyldithiocarbamate.
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Suicide potential and behavior in children ages 4 to 12.
From a population of 662 children 12 years of age and under, seen at the UCLA Neuropsychiatric Institute, during the years 1970 to 1974, 34 severely depressed children were identified who were also self-abusive and/or suicidal. Case study revealed fragmented, pathological homes, where the children's affect disorders and behaviors were symptomatic of acute family breakdown, marital disharmony, and observed and experienced violence, both verbal and physical. Follow-up on all available children, at least three years posttreatment, revealed that no child had committed suicide. Treatment evaluation by the parents was highly positive, with the great majority of children showing fair to good recovery and adjustment.
The amino acid sequence of dihydrofolate reductase from L1210 cells.
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The amino-acid sequence of the dihydrofolate reductase of a trimethoprim-resistant strain of Escherichia coli.
The determination of the amino acid sequence of the dihydrofolate reductase from Escherichia coli RT500 is described. The sequence, comprising 159 residues, has been derived from automatic sequencing of the intact protein in conjunction with manual sequencing of lysine-blocked tryptic peptides, Staphylococcus aureus protease peptides, and alpha-lytic protease peptides. Comparison of the sequence with that of the dihydrofolate reductase from a methotrexate-resistant strain of E. coli (MB1428) shows that 145 of the residues are identical. The distribution of the differences along the length of the molecule is discussed.
Professionalism and accountability. Controlling health services in the United States and West Germany.
This paper examines the new Professional Standards Review Organizations (PSROs) program in light of a similar program ("Economic Monitoring") that has been used in West Germany for over forty years. In the first section the PSRO program is described as government-mandated peer review by professional organizations, and is compared with that of the West Germany system. The second section argues that the PSROs are likely to strengthen the organization of established medicine, to increase the bargaining power of professional organizations, and to further insulate professional behavior from public scrutiny. The third section describes some of the effects of bureaucratic rigidities in peer review on the practice of medicine: the preservation of old technologies, the development of fixed patterns of practice, and the strengthening of the technical and interventionist biases in medical care. The final section evaluates the PSRO program as a complete delegation of congressional authority and a failure of Congress to set any rules for the development and application of norms and standards. The lack of any mechanism for accountability of the PSROs to public and choices is emphasized.
Observations of the haemodynamics of mexiletine.
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Nine-one-one.
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The training of the emergency medical technician.
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Letter: Thyroid-hormone levels and prognosis in patients with serious non-thyroidal illness.
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Fine structural studies of P-proteins in Cucurbita, Cucumis, and Nicotiana.
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Studies on the heterogeneity of subfragment-1 preparations. Isolation of a new proteolytic fragment of the heavy chain of myosin.
1. The physical, chemical and enzymic properties of subfragment 1 prepared from myosin of rabbit skeletal muscle by using two different concentrations of insoluble papain were compared. 2. Subfragment 1 prepared by using a myosin/papain ratio of 2000: 1 (by wt.) migrated on electrophoresis in non-dissociating conditions as a single enzymically active band. When prepared with a myosin/papain ratio of 200: 1 the preparation consisted of two enzymically active components of slightly different electrophoretic mobility. 3. The two types of preparation were obtained in similar yield and possessed similar specific adenosine triphosphatase activities when determined in the presence of Ca(2+). 4. Gel electrophoresis in the presence of 8m-urea showed that both preparations contained three light components. The component of molecular weight 15500 was apparently identical with one of the light-chain components of myosin (Ml(1)). The other two light-chain components of subfragment 1 were not identical with any of the light-chain components of myosin. 5. The heavy-chain fraction of subfragment 1 prepared by using low concentrations of papain dissociated into components with molecular weights of 87000, 69000 and 26000 on electrophoresis in sodium dodecyl sulphate. The heavy-chain fraction of subfragment 1 prepared by using higher concentrations of papain contained components with molecular weights of 69000 and 53000 and relatively increased amounts of the component of molecular weight 26000. 6. The isolated 26000 dalton component had an amino acid composition similar to that of the heavy-chain fraction of subfragment 1 and contained 3-methylhistidine and mono-and tri-N(epsilon)-methyl-lysine. It was homogeneous on electrophoresis in the presence of sodium dodecyl sulphate but gave two bands on electrophoresis in 8m-urea.
Treating the dry skin syndrome. Regional experiences with a micro-emulsion lotion.
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Specialist-professional intervention: an expanding role in the care and treatment of the retarded and their families.
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Possibility of in vitro alterations in cultures of mammary carcinoma cells, and altered immunological response in the rat: acquired capacity to reject injections of mammary carcinoma cells and implants of mammary carcinoma.
Cell cultures derived from a mammary adenocarcinoma carried in inbred Fisher (CDF) strain female rats, have been shown to possess oncogenic activities and on injection into control rats to produce mammary carcinomata with a failure rate of only one out of 25 rats (i.e. 4%). Efforts have been made to alter the cultured cells, or to select populations from them, so that the response in rats to their antigenic characteristics might leave them with the ability to then reject injections of the active, untreated cancer cells. We have found that continuous treatment of the cultures by their own cell debris (sonicate), or by relatively high concentrations of intact, salmon-sperm DNA, lead to cell populations which have a decreased potential to produce mammary carcinomata, with a combined failure rate of 9 out of 12 rats (i.e. 75%): 5 out of these 12 rats (i.e. 41·7%) did not exhibit any growth (carcinomata or granulomata) after injection of these treated cells, and now all 5 (i.e. 100%) have the capacity to reject injections of the untreated, active cancer cells. Four of these rats (one died under anaesthesia) have now been found to also reject implants of the carcinoma itself.