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Biomedical subjects

G Holt

Publications and source records attributed to G Holt.

At least 73 records · Page 4Linked to original sources
PubMed1988

Brucellosis complicated by aortic valve endocarditis.

A 30 year old veterinary surgeon developed a febrile illness with serological evidence of Brucellosis. He was known to have aortic valve disease and during the course of the illness, the clinical features of endocarditis became evident, with a vegetation visible echocardiographically on the aortic valve. Because of persisting fever despite appropriate antibiotic therapy, aortic valve replacement with a viable cryopreserved allograft aortic valve was undertaken. Organisms consistent with Brucella species were demonstrated in the excised vegetation. The patient received a six week course of antibiotics and his post-operative course was uneventful.

Adult↗
PubMed1986

Isolation of mutants sensitive to 2-aminopurine and alkylating agents and evidence for the role of DNA methylation in Penicillium chrysogenum.

Using high performance liquid chromatography, the presence of N6-methyladenine has been found at a level of 0.1 mol percent in DNA extracted from Penicillium chrysogenum. No 5-methylcytosine was detected. A mutant strain HP547, which is sensitive to the lethal effects of N-methyl-N'-nitro-N-nitrosoguanidine, methylmethane sulphonate and the base analogue 2-aminopurine shows an increased spontaneous mutation rate and no detectable DNA methylation. Comparison of restriction enzyme digests of wild type and undermethylated strains indicated that methylation was occurring at a different sequence to that of the Dam methylase system of E. coli.

2-Aminopurine↗
PubMed1985

High-performance liquid affinity chromatography of beta-lactamase.

New silica and organic polymer-based, wide-pore, affinity chromatographic phases have been developed for beta-lactamase purification. The resins have been evaluated in terms of binding capacity, ligand coverage, protein recovery and long-term stability of activated resins prior to ligand attachment. The columns have been applied to the isolation of beta-lactamase from fermentation media. Protein purity following high-performance liquid affinity chromatography was assessed by polyacrylamide gel electrophoresis.

Chromatography, Affinity↗
PubMed1985

High-performance liquid chromatographic identification of beta-lactam antibiotics produced by dermatophytes.

Thirteen of 48 dermatophyte isolates were found by bioassay to produce beta-lactam antibiotics and seven produced other antibiotics. Estimation and detection of specific beta-lactams in culture broths by derivatization and HPLC was only possible following concentration and extraction procedures. Analysis of the concentrated broths demonstrated the production of penicillin X and penicillin G by two Trichophyton mentagrophytes strains and by one Microsporum canis strain; one further T. mentagrophytes strain produced only penicillin X. Additions of the beta-lactam side-chain precursors, phenylacetic acid and phenoxyacetic acid, to fermentation media failed to increase the antibiotic titres.

Anti-Bacterial Agents↗
PubMed1984

Aspergillic acids produced by mixed cultures of Aspergillus flavus and Aspergillus nidulans.

A mixed culture of Aspergillus nidulans (GH79) and Aspergillus flavus (CMI 91019B) produced two antibiotics, designated VI and VII, which were not elaborated when either fungus was grown alone. Chemical and spectroscopic analysis of VI, the major component, indicated that this compound was identical to hydroxyaspergillic acid. The minor component, VII, was produced in too low a yield for its identity to be established. However, partial characterization suggests that this antibiotic also belongs to the aspergillic acid group of mycotoxins.

Anti-Bacterial Agents↗
PubMed1983

Serum thyroglobulin after mantle irradiation for Hodgkin's disease.

Thyroid function and serum thyroglobulin levels were studied in 66 subjects whose Hodgkin's disease had been previously treated by cervical, mediastinal and axillary lymph node (mantle) irradiation. Three patients were already undergoing treatment for thyroid disorders (one for primary hypothyroidism, two for Graves' disease) and a fourth was found to have euthyroid Graves' disease. 36 (Group I) of the remaining 62 patients had normal free thyroxine indices, normal basal thyrotrophin (TSH) levels and normal TSH response to thyrotrophin releasing factor (TRH). In 20 patients (Group II) free thyroxine indices were normal but either basal TSH levels were raised or normal basal TSH levels were associated with an exaggerated response to TRH. In 6 patients (Group III) free thyroxine indices were subnormal. Although results of thyroid function tests in group I lay within the normal range, the mean free thyroxine index was significantly lower and mean basal and peak TSH levels were significantly higher than those of a group of 35 normal subjects, indicating mild thyroid hypofunction. Elevated thyroglobulin levels were demonstrated in 11 irradiated subjects (18%). Mean thyroglobulin levels were significantly raised in each of the three groups of irradiated subjects. Significant positive correlations were found between log serum thyroglobulin and log basal TSH (r = 0.453, P less than 0.001) and log peak TSH (r = 0.515, P less than 0.001) levels. Mild thyroid hypofunction is common after mantle irradiation for Hodgkin's disease and raised serum thyroglobulin levels are a sensitive indicator of TSH stimulation of the damaged thyroid gland.

Adolescent↗
PubMed1981

Intergeneric cosynthesis of penicillin by strains of Penicillium chrysogenum, P. chrysogenum/notatum and Aspergillus nidulans.

A number of mutants impaired in penicillin production have previously been isolated from Penicillium chrysogenum and Aspergillus nidulans. During cofermentation of osmotically fragile mycelia derived from these strains, in the presence of inhibitors of cell wall regeneration, intergeneric cosynthesis has been demonstrated between mutants which are probably impaired in different parts of th penicillin biosynthetic pathway.

Aspergillus nidulans↗
PubMed1981

Interactions between dermatophyte fungi and staphylococci or Brevibacterium in vitro.

Interactions between dermatophyte fungi and staphylococci or brevibacteria on a new skin-based culture medium are described. Penicillin production by the fungus selects penicillin resistant S. aureus or B. epidermidis. Fungi are inhibited by brevibacteria but not by the staphylococci. "Keratolysis" by fungi may contribute to the growth nutrients of staphylococci.

Arthrodermataceae↗