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Biomedical subjects

G A Morris

Publications and source records attributed to G A Morris.

26 records · Page 2Linked to original sources

Two-dimensional NMR spectroscopy of siomycin A. Proton--carbon-13 chemical shift correlation.

A trial application of a recent two-dimensional nuclear magnetic resonance experiment to the polypeptide antibiotic siomycin A is described. Proton--carbon-13 chemical shift correlation measures the proton and carbon-13 chemical shift for each directly bonded CH group in a molecule, in a single experiment. The resultant map of correlated chemical shifts enables the carbon-13 spectrum to be assigned directly from the known proton shifts, and allows individual proton signals to be identified without problems of overlap. The signal-to-noise ratio available from such techniques should enable their application to aqueous protein solutions using currently available high-field spectrometers.

Anti-Bacterial Agents↗

Application of 31P-NMR saturation transfer techniques to investigate phospholipid motion and organization in model and biological membranes.

The potential of 31P-NMR saturation transfer experiments for determining motional characteristics (in the millisecond to second time scale) of phospholipids in model and biological membranes is demonstrated. A technique to separate membrane phospholipid 31P-NMR signals from those of small water-soluble phosphates in intact cells in liver tissue is also illustrated.

Animals↗

Rupture of the quadriceps tendon: diagnosis by arthrography.

Arthrography revealed an abnormal tract of contrast agent dissecting from the suprapatellar bursa into the soft tissue anterior to the patella and downward to a level 9 cm beneath the tibial plateau in a patient with complete rupture of the quadriceps tendon. The bursal anatomy of the anterior portion of the knee is reviewed in relation to the capsule-forming structures of the quadriceps expansion. The use of knee arthrography for the assessment of quadriceps tendon injury is advocated.

Aged↗

Binding of a porphyrin conjugate of Hoechst 33258 to DNA. II. NMR spectroscopic studies detect multiple binding modes to a 12-mer nonself-complementary duplex DNA.

We have probed by 1H NMR spectroscopy the molecular basis of the interaction between Hoechst 33258 conjugated to a des-metalloporphyrin and a non self-complementary duplex DNA sequence, designed on the known chemical nuclease selectivity of this system. The imino NMR spectra are consistent with two distinct families of structure, that is, PORHOE binding either way along the duplex. 2D spectral, T2, and linewidth data suggest multiple species within the two conformational families.

Binding Sites↗

The distribution of Langerhans cells and CD1a antigen in healthy and diseased human gingiva.

The distribution of CD1a antigen in gingival epithelium of clinically healthy gingiva was examined and compared with the distribution in gingival epithelium of adult periodontitis lesions. Cryostat sections were examined with monoclonal antibodies to CD1a antigen using the ABC immunoperoxidase technique. In healthy gingiva, CD1a was limited to Langerhans cells (LC) which were observed throughout the length of the external epithelium and orosulcular epithelium. The numbers of LC expressed either per unit length of orosulcular epithelium or per mm2 were similar to the numbers in external gingiva. Junctional epithelium contained few if any dendritic LC. The numbers of LC in pocket epithelium of adult periodontitis lesions were significantly lower compared with orosulcular epithelium of healthy tissue and compared with external gingiva of diseased tissue (p less than 0.005). In many sections, no LC were identified in pocket epithelium. In 5 of 8 adult periodontitis sites, CD1a was also observed in association with the membranes of suprabasal keratinocytes in external and pocket epithelium in areas where no LC were identified. These findings provide further evidence that changes in gingival epithelial cells occur in periodontal disease which are analogous to those documented in dermatological diseases and suggest that epithelium may play a role in gingival homeostasis and in the pathogenesis of periodontal diseases.

Antibodies, Monoclonal↗