Search PubMed⌕ Search

Biomedical subjects

R M Mason

Publications and source records attributed to R M Mason.

At least 145 records · Page 8Linked to original sources
PubMed1980

Adenoid involution and developing hypernasality in cleft palate.

Information about the adenoid mass is reviewed, and the phenomenon of gradual development of hypernasality as a result of adenoidal involution is described in two patients selected from a sample of 122 with repaired cleft palate. Three types of radiographically determined closure patterns of the velum against the adenoid pad are presented. Our clinical experience suggests that the results of aerodynamic studies, completed on a longitudinal basis, may identify patients who are at risk in maintaining normal resonance balance one year or more in advance of perceptual or radiographic evidence of velopharyngeal incompetency.

Adenoidectomy↗
PubMed1979

Proteoglycan aggregates in adult human costal cartilage.

1. A sequential extraction procedure using isotonic KCl and 4.0 M guanidine hydrochloride was used to solubilise proteoglycans from adult human costal cartilage under conditions minimising autolysis. Up to 28% of the total tissue hexuronate was extracted. 2. Proteoglycan fractions were prepared from the extracts by CsCl equilibrium density gradient centrifugation. 3. Each fraction exhibited distinct electrophoretic heterogeneity. 4. Proteoglycans extracted by isotonic solutions are relatively small and may be in vivo degradation products of whole molecules. The major fraction (A1) from high ionic strength extracts has a composition similar to that of A1 proteoglycans from adult human articular cartilage. A2 fractions differ and are highly enriched in protein. 5. A1 and A2 fractions from high ionic strength extracts contain proteoglycan aggregates, but to a much lesser extent than found in other cartilages like bovine nasal or porcine epiglottal cartilage. 6. The aggregates can be dissociated and a 'subunit" proteoglycan isolated by CsCl density gradient centrifugation in 4.0 M guanidine hydrochloride. 'Subunits' can reaggregate partially, when mixed with fractions of lower density from the gradient. 7. Addition of hyaluronic acid to A1GuHCl promotes a large increase in the amount of aggregate present. 8. The hyaluronic acid content of costal cartilage is not deficient compared to that of other hyaline cartilages. 9. Polypeptides with molecular weights suggesting their identity as 'link proteins' are present in A1 and A2 fractions. 10. Additional polypeptides of higher molecular weight than link proteins are also present in A1 and A2 fractions. They may represent the hyaluronic acid binding region of proteoglycans and compete with 'whole' proteoglycans for hyaluronate in the tissue.

Animals↗
PubMed1979

Residual hypernasality in repaired cleft palate.

This article reviews selected components of the speech process in children with a repaired cleft palate in order to provide the speech-language pathologist with a framework for decision-making in the selection of appropriate identification and management strategies. Discussion is offered which intends to clarify the phenomena of velopharyngeal valving, nasality, and hypernasality. With an understanding of these fundamental phenomena, suggestions are proposed for management approaches which may be applied to the more common bases of hypernasality in children with repaired clefts.

Child↗
PubMed1978

Physicochemical properties of cartilage proteoglycans extracted by lanthanum chloride.

Bovine nasal cartilage was extracted with 0.5 M LaCl3 and the extract then diluted with nine volumes of water. The resulting precipitated (PLaCl3) contained the proteoglycan subunits, together with minor protein components, but was essentially free from hyaluronic acid. The properties of PLaCl3 were investigated by chemical analysis, electrophoresis, viscometry and analytical ultracentrifugation, and the results compared with those for proteoglycan obtained by caesium chloride density gradient centrifugation of 2 M CaCl2 cartilage extracts. Proteoglycan subunits (A1D1) prepared from PLaCl3 showed identical properties to those obtained from other high ionic strength cartilage extracts.

Animals↗
PubMed1977

Speech screening of children in the dental office.

Screening for speech problems in the dental office involves less than five minutes. Procedures include the sampling of a child's pronunciations in counting activities, word responses to pictures or questions, and conversational speech situations. Use of a normative sound development chart will help judge each child's pronunciation skills. Oral diadochokinetic testing provides a means of evaluating the maturational level of the neuromotor components of the oral structures used in support of sound production. Finally, the child's ability to modify sound production after stimulation, that is, his "stimulability," adds important data for determining the child's potential for outgrowing his problem. The screening assessment of these several characteristics of speech performance, then, provides sufficient diagnostic criteria for the dentist to recommend those children for speech therapy whose error productions will not likely improve through maturation alone. In instances where examination indicates that maturation should cause spontaneous improvement of speech, the dentist would then be able to inform the parents.

Age Factors↗
PubMed1976

The electrophoretic heterogeneity of bovine nasal cartilage proteoglycans.

1. Proteoglycans were extracted from bovine nasal cartilage with 2.0M-CaC2 or with 0.15M-KCl followed by 2.0M-CaC2.. Proteoglycan fractions were prepared from the extracts by density-gradient centrifugation in CsCl under 'associative' and 'dissociative' conditions. 2. The heterogeneity of the proteoglycan fractions was investigated by large-pore-gel electrophoresis. It was concluded that extracts made with 2.0M-CaCl2 or sequential 2.0M-CaCl2 contain two major species of proteoglycan 'subunit' of different hydrodynamic size, together with proteoglycan aggregates. Both 'subunits' have mobilities that are greater than those of proteoglycans obtained from pig articular cartilage McDevitt & Muir (1971) Anal. Biochem. 44, 612-622] and are therefore probably smaller in size than the latter. 3. Proteoglycan fractions isolated from cartilage extracted lith 0.15M-KCl separated into two main components on large-pore-gel electrophoresis with mobilities greater than those of proteoglycans extracted with 2.0M-CaCl2. Proteoglycans extracted at low ionic strength from bovine nasal cartilage are of similar hydrodynamic size to those extracted from pig articular cartilage under the same conditions [McDevitt & Muir (1971) Anal. Biochem. 44, 612-622]. 4. The role of endogenous proteolytic enzymes in producing proteoglycan heterogeneity, particularly in low-ionic-strength cartilage extracts is discussed. 5. Hyaluronic acid and 'link proteins' were present in the proteoglycan fraction separated from KCl extracts as well as in the fraction separated from CaCl2 extracts. Hyaluronic acid can only be identified in proteoglycan fractions by large-pore-gel electrophoresis after proteolysis and further purification of the fraction. 6. Collagen was extracted by both salt solutions and was tentatively identified as type II. Small amounts of collagen appear to be associated with the proteoglycan-aggregate fraction from the high-ionic-strength extract but not with the corresponding fraction from the KCl extract.

Animals↗
PubMed1975

Comparison of fixed interval and visual analogue scales for rating chronic pain.

A visual analogue scale (VAS) and a 4-point scale (FPS) have been compared in patients suffering from prolonged constant pain due to chronic inflammatory or degenerative arthropathy. Each patient was treated with a constant low or high dose of paracetamol or dihydrocodeine throughout a four week period. The VAS was accurate, as reliable and more sensitive than the FPS in registering the intensity of chronic pain. Separate records of each estimate, sealed immediately on completion by the patient, resulted in omission of significantly more pain recordings on the FPS, whereas retention by the patients of their previous records did not systematically influence subsequent judgments. In this study, the VAS appeared to be more satisfactory than the FPS for patient self-rating of pain intensity.

Acetaminophen↗
PubMed1975

Synthetic D(-)penicillamine in rheumatoid arthritis. Double-blind controlled study of a high and low dosage regimen.

Doses of 600 mg and 1200 mg of D(-)penicillamine daily were superior to a standard regimen of therapy in rheumatoid arthritis. The higher dose did not produce significantly greater therapeutic benefit in the group of patients so treated, although individual patients sometimes improved more. The frequency of rashes, blood dyscrasias, and withdrawals from the trial increased withe dosage. It is concluded that D(-)penicillamine is a useful treatment that the daily dose should be as low as possible, and that it should be increased at infrequent intervals only, with due regard to the likelihood of further improvement in relation to an increased risk of adverse reactions.

Acetaminophen↗
PubMed1974

Comparison of azathioprine, cyclophosphamide, and gold in treatment of rheumatoid arthritis.

Azathioprine, cyclophosphamide, and gold have been compared under double-blind conditions in the treatment of relatively early rheumatoid arthritis. Over 18 months the two "immunosuppressive" agents produced clinical improvement comparable to that achieved with gold, and they also facilitated a reduction in the dosage of corticosteroids and retarded radiological joint deterioration. Drug management was easiest with azathioprine. Cyclophosphamide was perhaps marginally the most effective drug but it produced azoospermia in males. If the long-term hazards of malignancy and mutagenesis prove to be acceptable then the anti-proliferative agents provide a useful alternative to gold therapy and can with advantage be given relatively early in the course of rheumatoid arthritis.

Adult↗