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Biomedical subjects

S L Cheeseman

Publications and source records attributed to S L Cheeseman.

8 recordsLinked to original sources

A 'modified de Gramont' regimen of fluorouracil, alone and with oxaliplatin, for advanced colorectal cancer.

The standard de Gramont (dG) regimen of fortnightly leucovorin, bolus fluorouracil and 22-h infusion of fluorouracil, d1+2, and the same regimen plus oxaliplatin, are effective but also cumbersome. We therefore present simplified 'Modified de Gramont' (MdG) regimens. Forty-six advanced gastrointestinal cancer patients entered a dose-exploring study of MdG, including an expanded cohort of colorectal cancer patients at optimum dose. Treatment (fortnightly) comprised: 2-h i.v.i. leucovorin (350 mg d,l-LV or 175 mg l-LV, not adjusted for patient surface area); bolus fluorouracil (400 mg m(-2)), then ambulatory 46-h fluorouracil infusion (2000-3600 mg m(-2), cohort escalation). Subsequently, 62 colorectal patients (25 unpretreated; 37 fluorouracil-resistant) received MdG plus oxaliplatin (OxMdG) 85 mg m(-2). Fluorouracil pharmacokinetics during MdG were compared with dG. The optimum fluorouracil doses for MdG alone were determined as 400 mg m(-2) bolus + 2800 mg m(-2) 46-h infusion. A lower dose of 400 mg m(-2) bolus + 2400 mg m(-2) infusion which, like dG produces minimal toxicity, was chosen for the OxMdG combination. Fluorouracil exposure (AUC(0-48 h)) at this lower dose is equivalent to dG. With OxMdG, grade 3-4 toxicity was rare (neutropenia 2.8% cycles; vomiting or diarrhoea <1% cycles), but despite this there were two infection-associated deaths. Oxaliplatin was omitted for cumulative neurotoxicity in 17 out of 62 patients. Objective responses in colorectal cancer patients were: 1st-line MdG (22 assessable): PR=36%, NC=32%, PD=32%. 1st-line OxMdG (24 assessable): CR/PR=72%; NC=20%; PD=8%; 2nd line OxMdG (34 assessable): PR=12%; NC=38%; PD=50%. MdG and OxMdG are convenient and well-tolerated. OxMdG was particularly active as 1st-line treatment of advanced colorectal cancer. Both regimens are being further evaluated in the current UK MRC phase III trial.

Adenocarcinoma↗

Phase I and pharmacologic study of CT-2584 HMS, a modulator of phosphatidic acid, in adult patients with solid tumours.

CT-2584 HMS, 1-(11-dodecylamino-10-hydroxyundecyl)-3, 7-dimethylxanthine-hydrogen methanesulphonate, is a modulator of intracellular phosphatidic acid. We treated 30 patients as part of a Phase I and pharmacokinetic study to determine the maximum-tolerated dose of CT-2584 HMS, toxicity profiles, pharmacokinetic profile and antitumour effects at escalating dose levels. CT-2584 HMS was given as a continuous infusion for 6 hours for 5 consecutive days every 3 weeks. Plasma samples for pharmacokinetic studies were analysed using a validated high-performance liquid chromatographic assay. Mean C(max)and AUC values for each dose group were similar on days 1 and 5 and increases in plasma concentration (C(max)and AUC) appeared proportional to the dose. CT-2584 HMS had a mean elimination half-life of 7.3 hours. Values of V(d)and clearance were independent of dose and duration of treatment. Dose escalation was halted at 585 mg/m(2)because of malaise and lethargy, which was sometimes accompanied by nausea and headache. 26 patients were evaluable for response, one patient with pleural mesothelioma achieved a partial response to treatment confirmed by CT scanning. A dose level of 520 mg/m(2)daily x 5 days would be suitable for Phase II testing. Alternative schedules of CT-2584 HMS to overcome the limiting toxicity of malaise would be worthy of examination.

Adult↗

Bulleidia extructa gen. nov., sp. nov., isolated from the oral cavity.

Five strains of anaerobic non-sporing Gram-positive bacilli isolated from advanced periodontitis (four strains) and a dentoalveolar abscess (one strain) that did not correspond to existing species were subjected to phenotypic and genetic characterization. Following 16S rDNA sequence analysis, they were found to constitute a novel branch of the low G+C Gram-positive division of the phylogenetic tree related to Erysipelothrix rhusiopathiae and Holdemania filiformis. A new genus Bulleidia, and the species Bulleidia extructa, are proposed. Growth of B. extructa in broth media was poor but was enhanced by the addition of fructose, glucose or maltose together with Tween 80. Glucose and maltose were fermented and arginine was hydrolysed. Acetate, lactate and trace amounts of succinate were the end products of glucose fermentation. The G+C content of the DNA of the type strain is 38 mol%. The type strain of Bulleidia extructa is DSM 13220T.

Bacteria, Anaerobic↗

Cerebral metastases in malignant mesothelioma: a case report.

A case of a 61-year-old man with metastatic malignant mesothelioma is described. Four months after diagnosis the patient commenced chemotherapy with liposomal doxorubicin as part of an EORTC phase II trial. He developed signs of intracerebral metastases after his fourth cycle of chemotherapy and died shortly after. Malignant mesothelioma is traditionally viewed as a disease that spreads locally but metastasizes rarely. We describe in detail this case and suggest that metastases in this disease are not as uncommon as originally proposed.

Brain Neoplasms↗

Identification and discrimination of oral asaccharolytic Eubacterium spp. by pyrolysis mass spectrometry and artificial neural networks.

Curie-point pyrolysis mass spectra were obtained from 29 oral asaccharolytic Eubacterium strains and 6 abscess isolates previously identified as Peptostreptococcus heliotrinreducens. Pyrolysis mass spectrometry (PyMS) with cluster analysis was able to clarify the taxonomic position of this group of organisms. Artificial neural networks (ANNS) were then trained by supervised learning (with the back-propagation algorithm) to recognize the strains from their pyrolysis mass spectra; all Eubacterium strains were correctly identified, and the abscess isolates were identified as un-named Eubacterium taxon C2 and were distinct from the type strain of P. heliotrinreducens. These results demonstrate that the combination of PyMS and ANNs provides a rapid and accurate identification technique.

Bacterial Typing Techniques↗

Phylogeny of oral asaccharolytic Eubacterium species determined by 16S ribosomal DNA sequence comparison and proposal of Eubacterium infirmum sp. nov. and Eubacterium tardum sp. nov.

16S rRNA gene sequences of Eubacterium brachy, Eubacterium nodatum, Eubacterium saphenum, Eubacterium timidum, and two previously unnamed taxa were determined. The results of a phylogenetic analysis indicated that all of the strains sequenced belonged to a deep branch of the low-G+C-content gram-positive group. The levels of 16S ribosomal DNA sequence similarity between species were low, suggesting that a number of genera may be represented in this group. The representatives of the two unnamed taxa, which were isolated from patients with periodontitis, were clearly distinct from the previously described species, and, therefore, the following two new species are proposed: Eubacterium infirmum (type strain, NCTC 12940) and Eubacterium tardum (type strain, NCTC 12941).

Base Sequence↗

An unclassified Eubacterium taxon in acute dento-alveolar abscess.

The microflora of pus samples aspirated from 50 acute dento-alveolar abscesses was examined. A total of 143 bacterial strains was isolated, consisting predominantly of Prevotella spp., alpha-haemolytic Streptococcus spp., Peptostreptococcus spp. and Eubacterium spp. An unclassified asaccharolytic Eubacterium taxon was encountered in 17 (34%) of the abscesses. This taxon was found to have a positive association with Fusobacterium spp. and a negative association with alpha-haemolytic Streptococcus spp.

Acute Disease↗