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Biomedical subjects

N Cooke

Publications and source records attributed to N Cooke.

6 recordsLinked to original sources
PubMed1992

Prediction of migration behavior of oligonucleotides in capillary gel electrophoresis.

The influence of the primary structure (base composition) on the electrophoretic migration properties of single-stranded oligodeoxyribonucleotides in capillary polyacrylamide gel electrophoresis was investigated using homo- and heterooligomers under denaturing and non-denaturing conditions. Homooligodeoxyribonucleotides of equal chain lengths but of different base composition showed significant differences in mobility. In addition, the migration properties of heterooligomers were found to be highly dependent on their base composition. A simple equation is presented for predicting relative migration times using denaturing and non-denaturing polyacrylamide capillary gel electrophoresis. Orange-G was used as an internal standard and as the basis of the relative migration time calculations. Examples are presented using homo- and heterooligomers in the 10-20-mer range to show the correlation of the primary structure and their predicted and observed migration rates.

Base Sequence↗
PubMed1992

Establishing the limits of the Mini-Mental State. Examination of 'subtests'.

It has been suggested that the Mini-Mental State examination can be used to examine a patient's cognitive profile. We therefore examined the validity of Mini-Mental State subtests and individual items. The memory item, attention-concentration items, and constructional item had satisfactory sensitivity-specificity and correlated significantly with scores on neuropsychological tests. In contrast, four of the five Mini-Mental State language items had very low sensitivity, and three of five failed to correlate with neuropsychological test scores. These findings establish limits with regard to the ability of the Mini-Mental State to generate a cognitive profile. Our data also provide information regarding validity, difficulty level, and optimal cutoff scores for widely used mental status tasks.

Adult↗
PubMed1991

Capillary gel affinity electrophoresis of DNA fragments.

The incorporation of an affinity ligand within a polyacrylamide gel provides a general means of manipulating the selectivity of capillary gel electrophoresis separations. As an example of this approach, high resolution of DNA restriction fragments by capillary gel affinity electrophoresis has been achieved by adding a soluble intercalating agent, ethidium bromide, to the gel-buffer system. A migration model has been developed that can be used for selectivity optimization. Various parameters, such as ligand concentration and applied electric field, have been examined in terms of their influence on retention and selectivity of different-size DNA molecules. From this study, high-resolution separations have been developed with efficiencies as high as 10(7) theoretical plates per meter.

Chromatography, Affinity↗
PubMed1978

Antacid-induced osteomalacia and nephrolithiasis.

A 36-year-old woman suffered from bone pain, muscle weakness, and renal stones after prolonged ingestion of antacids for esophageal reflux. Investigation disclosed hypophosphatemia, hypercalciuria, and osteomalacia by bone biopsy. All symptoms and abnormal laboratory findings reversed with a regimen of oral phosphate supplementation and cessation of antacid intake.

Adult↗
PubMed1977

Hypercalcemic hyperparathyroidism in hypophosphatemic rickets.

A 25-year-old white woman with sporadic hypophosphatemic rickets presented with a 7 year history of chronic mild hypercalcemia, osteitis fibrosa cystic and hypercalcemic nephropathy. Serum immunoreactive parathyroid hormone was elevated by greater than 100-fold and a 3.5 g parathyroid tumor was found at operation. Survey of the literature reveals that of 9 previous cases in which hypercalcemic hyperparathyroidism occurred in association with hypophosphatemic rickets, only two had classical x-linked familial hypophosphatemic rickets. It appears more than likely that this unusual combination of skeletal diseases represents the chance occurrence of primary hyperparathyroidism in patients with underlying x-linked familial hypophosphatemic rickets rather than a complication of phosphate therapy.

Adolescent↗