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Biomedical subjects

C D Welch

Publications and source records attributed to C D Welch.

5 recordsLinked to original sources

Functional regulator therapy for cleft palate patients.

Nine cleft lip and palate children exhibiting collapse of maxillary segments and cross-bite were treated orthodontically with the functional regulator (FR) for periods ranging from 6 to 18 months. The purpose of this investigation was to evaluate quantitatively treatment of cleft palate patients with the functional regulator and to evaluate the effect of the appliance on their speech. Cleft palate patients typically have speech, nose, and lip defects which make patient cooperation and appliance acceptance more difficult. However, patient cooperation was considered good with an average mean of 12.7 hours per day of appliance wear and a range of 5.6 to 18.2 hours. Change in interimplant dimension was measured on frontal radiographs, and dental changes were measured of serial dental casts. The resulting data indicated no significant change in maxillary width or cross-bite relationship. The functional regulator was not clinically useful in this sample when the treatment objective was primary expansion of collapsed maxillary segments in the cleft palate patient. Good speech-production skills prior to treatment will minimize the adverse effect that the FR has on speech intelligibility. A significant amount of accommodation to the appliance occurs within 1 week after insertion, but maximum improvement in speech intelligibility occurs with full-time wear of the appliance for as many hours per day as possible.

Activator Appliances↗

Complete amino acid sequence of human phosphoglycerate kinase. Cyanogen bromide peptides and complete amino acid sequence.

Cyanogen bromide treatment of reduced, S-carboxymethylated phosphoglycerate kinase yielded 14 major peptides, CNBr-1 (20 residues), CNBr-2 (8 residues), CNBr-3 (33 residues), CNBr-4 (11 residues), CNBr-5 (104 residues), CNBr-6 (14 residues), CNBr-7 (37 residues), CNBr-8 (7 residues), CNBr-9 (6 residues), CNBr-10 (11 residues), CNBr-11 (19 residues), CNBr-12 (42 residues), CNBr-13 (44 residues), and CNBr-14 (61 residues). The amino acid sequences of all the cyanogen bromide peptides were determined by a combination of automated and manual sequence analysis, and the characterization of tryptic and chymotryptic peptides and peptides obtained by digestion with staphylococcal protease. Two tryptic peptides which were not obtained by direct digestion of whole phosphoglycerate kinase were recovered from cyanogen bromide Peptides CNBr-13 and CNBr-14 and these peptides were purified and sequenced. Based on the information from all the tryptic and cyanogen bromide peptides derived from the enzyme, the proper alignment of these peptides was made. Thus, complete amino acid sequence of human phosphoglycerate kinase consisting of 417 amino acid residues was determined.

Amino Acid Sequence↗

The identification and measurement of two new metabolites of naltrexone in human urine.

Two metabolites of naltrexone were identified in human and rat urine following drug administration. The metabolites, 2-hydroxy-3-0-methylnatrexone and 2-hydroxy-3-0-methyl-6 beta-naltrexol, were identified by comparison of their respective gas chromatographic retention times and methane chemical ionization spectral patterns with authentic standards. The standards were obtained by chemical synthesis from naltrexone. Urinary excretion of the two metabolites was measured by single ion recording of the pseudomolecular ions of the metabolites and an internal standard. Excretion data was collected from 5 human subjects over a period of 5 days following a single dose of naltrexone. The metabolites, 2-hydroxy-3-0-methylnatrexone and 2-hydroxy-3-0-methyl-6 beta-natrexol were found to account for an average (+/- standard error) of 0.45 +/- 0.08% and 4.6 +/- 2.1% of the administered dose, respectively. An unusually long half-life of elimination of the latter metabolite (mean of 20.2 +/- 1.8 hr) was observed. Acid-hydrolysis of the samples failed to produce a significant increase of either metabolite indicating that the major protion of these metabolites is excreted in the free form.

Animals↗