Search PubMed⌕ Search

Biomedical subjects

C Williamson

Publications and source records attributed to C Williamson.

At least 109 records · Page 6Linked to original sources
PubMed1988

Dominant, challenging and repressed interests in the NHS.

Examining New York's health care system, Alford noted that the most powerful interests were those of the professionals, whose values were widely accepted by society. Managers, with different and sometimes conflicting interests were less powerful but had much influence. The interests of groups in the community, however, had little voice or influence and were harmed by the others. Charlotte Williamson applies this theory to explain important features of the British scene. Values are not confined to the interest group which they reflect, so that on the one hand CHCs can support measures which are in the interest of staff rather than patients, and on the other hand advocates of community interests will sometimes support the values of professions or of managers.

Community Health Centers↗
PubMed1987

The role of intravenous digital subtraction angiography as an adjunct to computed tomography in the preoperative assessment of patients with abdominal aortic aneurysm.

The purpose of this article is to determine the role of intravenous digital subtraction angiography (IV-DSA) as an adjunct to computed tomography (CT) in the preoperative evaluation of patients with abdominal aortic aneurysm. Sixty-six patients underwent IV-DSA as well as CT during a 2-year period. Sixty-four of the 66 patients underwent abdominal aortic aneurysm repair. The results of the 66 patients were analyzed to assess what additional information was obtained by IV-DSA concerning aneurysm size, vascular anomalies, visceral arterial anatomy, associated aneurysmal disease, and iliofemoral and distal occlusive disease. On the basis of this study, it is suggested that IV-DSA has a limited role in the preoperative evaluation of patients with abdominal aortic aneurysm.

Aged↗
PubMed1986

Malignant melanoma in relation to moles, pigmentation, and exposure to fluorescent and other lighting sources.

Interviews were performed on 83 patients with malignant melanoma, being 74% of all new NHS patients over a 33 month period who were resident in a defined area of Nottingham, and on age and sex matched controls chosen from all outpatients and inpatients of the same hospitals with the same area of residence. Significantly increased risks of melanoma were found in subjects with 3 or more raised moles on the upper arms (relative risk = 17.0), in association with heavy freckling of the face and arms, and with a tendency to sunburn easily and tan poorly, these factors having independent effects. While no significant and consistent association with exposure to fluorescent light was seen, the observed risks were higher in subjects with greater exposure, and higher in association with exposure to undiffused than to diffused light. Cases had a significantly greater number of hours' exposure to undiffused light than did controls. The associations with fluorescent light exposure were stronger when based on interview data than on a subsequent postal questionnaire. Twenty-one cases and 11 controls reported exposure to unusual occupational lighting sources which may have had an ultraviolet component; these included various intense lighting sources and lamps used in printing and dyeline copying.

Adolescent↗
PubMed1986

Coding sequence of the precursor of the beta subunit of rat propionyl-CoA carboxylase.

A cDNA encoding the cytoplasmic precursor of the beta subunit of the mitochondrial enzyme propionyl-CoA carboxylase (EC 6.4.1.3) was cloned and sequenced. The DNA sequence of 2070 nucleotides is almost identical in size to the major hybridizing mRNA from rat liver (2000 +/- 50 nucleotides), suggesting that the cloned DNA represents nearly all of the mRNA sequence. A polypeptide expressed in vitro from an mRNA transcript of this cDNA is indistinguishable in size from the beta subunit precursor (58,500 Da). An open reading frame of 1623 nucleotides, flanked by stop codons, encodes a polypeptide of 541 amino acids; the predicted amino acid sequence was confirmed as that of the beta subunit of propionyl-CoA carboxylase by matching it to the amino acid sequences of five peptides derived from pure mature rat enzyme. Although the exact length of the cleavable, NH2-terminal leader peptide has not been determined because the NH2-terminal residue of the mature subunit is blocked, the leader is most likely 40-42 amino acids in length and is highly positively charged. Computer-aided analysis of secondary structure suggests that the leader peptide consists of two alpha-helical segments, with the two most NH2-terminal arginine residues occupying opposite sites of the first helix; this helix has no apparent hydrophobic moment.

Amino Acid Sequence↗
PubMed1983

Abnormal radiosensitizing and cytotoxic properties of ortho-substituted nitroimidazoles.

Various 5-substituted 4-nitroimidazoles have been shown to be much more efficient radiosensitizers and much more toxic than would have been predicted from their electron affinities, as measured by values of one-electron reduction potential, E17. Using Chinese hamster V79 cells in vitro, a comparison has been made with some isomeric 4-substituted 5-nitroimidazoles. These compounds have E17 values some 64mV greater than the 4-nitroimidazoles, yet show much lower sensitizing efficiency and also lower toxicity. Neither series of compounds shows the greater toxicity towards hypoxic cells usually associated with nitroaromatic and nitroheterocyclic compounds. The second-order rate constants, k2, for reaction of these isomeric nitroimidazoles with glutathione and dithiothreitol were determined. Within each series the value of k2 increased with increasing electron affinity, however, the 4-nitroimidazoles were always more reactive than their corresponding 5-nitro isomers. The sensitizing and toxic properties of these compounds may involve depletion of intracellular thiols; this possibility is discussed.

Animals↗
PubMed1981

Angiolymphoid hyperplasia with eosinophilia of the external ear canal.

Angioblastic lymphoid hyperplasia with eosinophilia, or Kimura's disease, is a clinically and histopathologically recognized entity that is characterized by cutaneous nodules, proliferating blood vessels with atypical histiocyte-like endothelial cells, and numerous eosinophils. It has been treated with steroids and by surgical excision, irradiation, cryotherapy, and electrodesiccation. Persistent residual disease and local recurrence are frequent. We review the literature and report two cases that involve the ear. We present the histopathologic and clinical results of laser removal of a conchal and external canal lesion.

Adult↗
PubMed1981

Cytotoxic properties of a 4-nitroimidazole (NSC 38087): a radiosensitizer of hypoxic cells in vitro.

5-Phenoxysulphonyl-1-methyl-4-nitroimidazole (NSC 38087) can act as a sensitizer of hypoxic mammalian cells to radiation in vitro. The degree of sensitization achieved is greater than would be predicted from the drug's electron affinity. Cytotoxicity studies have shown that 5 microM NSC 38087 can reduce the surviving fraction of log-phase V79 cells in air at 37 degrees C to 10(-2) after 2 h exposure. This toxicity is considerably increased by small rises in temperature. In contrast to other nitro-heterocyclic radiosensitizers, NSC 38087 and related 5-substituted 4-nitroimidazoles show greater toxicity towards aerobic than to hypoxic cells. Log-phase cells show the highest sensitivity to the toxic action of NSC 38087, with plateau-phase cells, cells with a history of chronic hypoxia, and thermotolerant cells showing greater resistance. These toxicity data are compared to those for the 2-nitroimidazole hypoxic-cell sensitizer misonidazole.

Animals↗
PubMed1981

Radiosensitization of hypoxic mammalian cells in vitro by some 5-substituted-4-nitroimidazoles.

The efficiencies of various 5-substituted-4-nitroimidazoles as radiation sensitizers have been determined in hypoxic Chinese hamster cells irradiated in vitro. Compared with published data on the sensitizing properties of substituted 2-nitro- and 5-nitroimidazoles, some of the 4-nitro derivatives show unusually high sensitizing efficiencies defined as the concentrations required to give an enhancement ratio of 1.6. The equilibrium one-electron reduction potentials of the compounds (E17) were measured by a pulse radiolysis technique and the results show that although sensitizing efficiencies are unexpectedly high, based on considerations of electron affinity, they still increase with increasing values of E17. Enhancement ratios were determined in two V79 cell lines for combinations of one of these compounds (a 4-nitroimidazole containing the group SO2.O.phenyl in the 5-position, NSC 38087) with various concentrations of misonidazole. The sensitization observed suggests that the two compounds may be operating by different mechanisms.

Animals↗
PubMed1980

Distribution of knowledge is the distribution of power.

Earlier this year the Journal published an article by Brian Watkin in which he criticised the contribution made to the NHS by many health authority members. Now Charlotte Williamson, a member of the North Yorkshire AHA, takes the debate a stage further. The specific remit of members, she argues, is to protect the interests of patients by ensuring resources are allocated in accordance with need, and proper standards of care are achieved.

Communication↗
PubMed1980

Combination studies with misonidazole and a cis-platinum complex: cytotoxicity and radiosensitization in vitro.

cis-Dichlorodiammineplatinum(II) (cis-Pt(II) can act as a radiosensitizer of hypoxic mammalian cells in vitro. Used in combination with misonidazole the level of sensitization achieved is greater than that seen with either drug alone, and it is suggested that these compounds sensitize by independent mechanisms. For cells held at 37 degrees C, cis-Pt(II) shows much greater toxicity to hypoxic cells than to aerobic cells. In combination with misonidazole, no additional cytotoxic effect is shown towards aerobic cells than that seen for cis-Pt(II) alone. However, there is additional killing of hypoxic cells when they are treated with both drugs.

Animals↗
PubMed1980

The interaction of misonidazole with radiation, chemotherapeutic agents, or heat: a preliminary report.

Survival of hypoxic cells exposed to misonidazole at 37 degrees C show an initial lag period after which survival decreases exponentially with time. Hypoxic cells incubated with misonidazole for a time equivalent to that of the lag period on the survival curve show increased sensitivity when subsequently given x-irradiation. This is consistent with previously published observations. In addition, preincubation of hypoxic cells with misonidazole ata 37 degrees C also renders cells more sensitive to subsequent treatments by heat or melphalan, mustine and cis-Pt(II). Preincubation must be in hypoxia for cells to become sensitive to a second insult; preincubation in air does not change cellular sensitivity even when this preexposure is 5 mM misonidazole for 3 days. The potential of exploiting a physiological property of most solid tumors, viz., hypoxia, in order to increase sensitivity of tumor cells to cytotoxic agents is discussed.

Animals↗