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Biomedical subjects

A Briddon

Publications and source records attributed to A Briddon.

12 recordsLinked to original sources
PubMed1998

Total plasma homocysteine as part of the routine aminogram by ion-exchange chromatography.

Ion-exchange chromatography (IEC) with ninhydrin post-column derivatisation is the only technique available for the assay of total, (free plus bound), cysteine and homocysteine which also enables the routine measurement of all other commonly occurring amino acids. IEC assay of total cysteine and homocysteine typically involves incubating buffered plasma for 60 minutes at 37 degrees C with dithiothreitol (DTT), but these assay conditions significantly extend total analysis time and compromise other amino acid values, notably glutamine and glutamate. However, it is possible to carry out the DTT reduction in plasma virtually instantaneously and without additional buffering, thus preserving the integrity of other diagnostically important amino acids. Assay precision is adequate for cardiovascular risk assessment.

Amino Acids↗
PubMed1996

Impairment of the nitric oxide/cyclic GMP pathway in cerebellar slices prepared from the hph-1 mouse.

In this study, the effect of tetrahydrobiopterin deficiency on the nitric oxide/cGMP pathway has been investigated in cerebellar slices derived from the hph-1 mouse. This animal displays a partial deficiency of tetrahydrobiopterin. Basal levels of cGMP were significantly reduced (-29.5%) in the hph-1 mouse cerebellum compared to controls. Following kainate stimulation (500 microM) cGMP levels increased in both control and hph-1 preparations but were again significantly lower (-29.1%) in the hph-1 mouse. Exposure of slices to the nitric oxide donors, S-nitroso-N-acetylpenicillamine and S-nitroso-glutathione, revealed no difference in cGMP accumulation between the two groups. These findings suggest that the cerebellar nitric oxide/cGMP pathway may be impaired in partial tetrahydrobiopterin deficiency states due to diminished nitric oxide formation.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed1996

Decision support techniques for the interpretation of quantitative amino acid data.

Quantitative amino acid profiles are traditionally reported as a list of individual concentrations and reference intervals. By the use of selected examples it is shown that alternative methods of presenting and assessing these results can enhance both the quantity and quality of information. A candidate decision support tool is offered as an aid to the interpretation of amino acid profiles.

Algorithms↗
PubMed1986

Sweat sodium related to amount of sweat after sweat test in children with and without cystic fibrosis.

The sweat concentration of sodium was found to be inversely correlated with the amount of sweat obtained after a sweat test according to the method of Gibson & Cook in children without and with cystic fibrosis. Reference intervals for sweat sodium overlapped for the two groups but two-dimensional reference distributions for the amount of sweat (range 20-440 mg) correlated with its sodium content were completely separated. The establishment of similar distributions in centres carrying out sweat tests could serve to assess the performance of this investigation at local level.

Adolescent↗
PubMed1984

Quantitative analysis of small intestinal mucosa in cow's milk-sensitive enteropathy.

The appearance of the small intestinal mucosa in cow's milk protein intolerance (CMPI) was studied using quantitative morphometry. The parameters under study were the numbers of eosinophil cells in the lamina propria and epithelium, villous height, crypt zone depth, villous height/crypt zone depth ratio, and total mucosal thickness. Tracings of whole sections were analysed using a suitably programmed minicomputer linked to a digitising table. Small bowel biopsy specimens from children with untreated CMPI, from children before and after clinical relapse on cow's milk challenges, and from children with resolved CMPI were compared to each other, to those from control infants, and to those from children with coeliac disease. No change of diagnostic significance could be found in the number of lamina propria eosinophil cells, but levels of intraepithelial eosinophils were significantly increased following cow's milk challenge. Quantification of mucosal dimensions confirmed the presence of a cow's milk-sensitive enteropathy and established the finding of a thin mucosa in CMPI regardless of clinical disease activity. Mucosal thickness was not different from control values following resolution of the disease. In coeliac disease mucosal thickness was significantly greater than in CMPI (apart from young children with untreated coeliac disease whose mucosa was not thicker than that of children with untreated CMPI) but not different from control values. It is suggested that in CMPI there is a limitation in the capacity of crypt cells to compensate for the loss of villous epithelium.

Biopsy↗
PubMed1978

3-Amino-2-piperidone in the urine of patients with hyperornithinemia.

3-Amino-2-piperidone, a delta-lactam of ornithine, has been detected in the urine of a number of patients with hyperornithinemia. The distinctive yellow colour formed with a ninhydrin-cadmium reagent should help in the detection of hyperornithinemia by urinary chromatography.

Adolescent↗