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Biomedical subjects

A J Bailey

Publications and source records attributed to A J Bailey.

At least 127 records · Page 7Linked to original sources
PubMed1984

Congenital dislocation of the hip: a possible inborn error of collagen metabolism.

Significant changes in the type of collagen, the fibril diameter and the nature of the crosslinks have been demonstrated in the joint capsules of subjects with congenital displacement of the hip (CDH). These changes are probably tissue specific since no detectable change could be observed in the skin of these subjects compared to controls. These preliminary biochemical studies clearly demonstrate that CDH involves an error in collagen metabolism.

Child, Preschool↗
PubMed1983

Separation of native types I and III collagens and denatured chains by reverse-phase high-performance liquid chromatography.

A simple and effective high-performance-liquid-chromatography system has been developed for the separation of the native forms of Types I and III collagens. This separation is achieved on a commercially available 330-A-pore-size C18 reverse-phase support using a solvent system consisting of ammonium bicarbonate (0.05 M) and trifluoroacetic acid (0.4%) with tetrahydrofuran as the eluting solvent. This simple system can also be applied to the separation of mixtures of the denatured chains of both collagen types.

Animals↗
PubMed1982

An immunocytochemical study of alpha-lactalbumin in human breast tissue.

The distribution of the milk protein, lactalbumin, has been studied in human breast tissue by the indirect immunoperoxidase technique on formalin fixed paraffin embedded sections. It was found in all lactating breasts examined and in all breasts from subjects who were more than 18 weeks pregnant. It was also seen in a small proportion of non-pregnant, non-lactating patients usually confined to small focal secretory lobular lesions known as lactational foci but also occasionally in morphologically normal lobules. Previous pregnancy does not appear to be a pre-requisite for lactalbumin secretion and our study suggests a possible relationship with usage of hormonal preparations. A wide variety of benign and malignant breast lesions were studied and none was found to contain the protein, except for fibroadenomas from patients who were pregnant or who harboured lactional foci. The absence of lactalbumin from all 44 breast carcinomas studied suggests that it has no role to play as a marker in the histopathological diagnosis or clinical monitoring of this disease.

Adult↗
PubMed1982

Immunofluorescence localization of type-M collagen in articular cartilage.

Normal mammalian articular cartilage has been found to contain several collagenous peptide chains in addition to type-II collagen. We now report the distribution in adult pig cartilage of one of these new peptides, type-M collagen, using type-specific antibodies. Type M is primarily located in the pericellular environment of the cells in the deeper zones of the articular cartilage. The distribution is shown to be distinct from that of type-II collagen. This finding suggests that type-M collagen may play an important role in the metabolism of articular cartilage.

Animals↗
PubMed1982

Collagen types in neuromuscular diseases.

The striking proliferation of connective tissue characteristic of the muscular dystrophies can be attributed predominantly to an increase in endomysial and perimysial type III collagen. Carriers of muscular dystrophy occasionally revealed a slight increase in anti-type III collagen fluorescence, but no abnormalities in collagen disposition were observed in foetuses "at risk" for DMD. In contrast, the proportion of collagen types in neurogenic atrophies appeared normal although anti-type IV and V staining, which delineated the basement membrane, was very intense around atrophied fibres, as was also the case in small fibres in myopathic diseases. The detection of staining with anti-type III, IV and V collagens in splits which are sometimes observed in hypertrophied fibres in the muscular dystrophies supports the suggestion that abnormalities in collagen production, perhaps involving a defective modulation of myoblast-fibroblast expression, may be involved in the pathogenesis of these diseases.

Adolescent↗
PubMed1982

Metabolism of rat skin collagen: the effect of arrested development and subsequent catch-up growth on the stability of the connective tissue fibers.

The growth of 33 day-old rats was temporarily arrested by feeding a low-protein diet for 6 weeks. The skin collagen hydroxyproline was labelled previously at 31 days by giving a single intraperitoneally injection of L-[5-3H] proline. This label was rapidly incorporated during the subsequent 2 days of normal growth and then remained at a steady level in the skin collagen when growth was halted. Control animals continued to incorporate label for 2 weeks and then the level of [3H] hydroxyproline declined as this label was subsequently lost from the skin collagen. During arrested development, the skin collagen became increasingly insoluble and the analysis of reducible crosslinks revealed a pattern similar to the collagen of an older animal. In addition the isometric tension developed per unit mass of collagen during thermal denaturation was three-fold greater than that from the age-matched control animals. Refeeding the normal diet gave an immediate burst of rapid growth. The pre-labelled collagen did not turnover during this period since there was no significant change in the level of labelled hydroxyproline in the skin. The newly synthesized collagen, which diluted out these older fibers, appeared to be immature, since it was initially rich in type III, it was very poorly crosslinked, and it caused a fall in the isometric tension value. It was concluded that there need not be limited degradation of the older collagen fibers in skin as an a priori requirement for growth.

Aging↗
PubMed1981

Thermal stability, mechanical properties and reducible cross-links of rat tail tendon in experimental diabetes.

Thermal stability (measured as isometric contraction force), biomechanical properties and reducible cross-links were measured in tail tendons from streptozotocin diabetic rats, with and without insulin treatment. After 10 days of diabetes the maximum thermal contraction force was unchanged, but the relaxation following the maximal contraction was retarded. After 30 days the maximum contraction force was increased and the relaxation rate was decreased. The maximum strength and stiffness of the tendons were increased after 10 days of diabetes and even more after 30 days. There was no change in the density of reducible cross-links. However, diabetes increased the amount of glucose attached to the lysine and hydroxylysine residues of collagen. Insulin treatment prevented all changes in thermal stability and mechanical properties. The results indicate that stabilization of collagen fibres in diabetes does not follow the same pattern as that seen in normal ageing.

Animals↗
PubMed1981

Characterization of N-glycosylated type I collagen in streptozotocin-induced diabetes.

The N epsilon-glycosylation of lysine and hydroxylysine residues in collagen from streptozotocin-induced-diabetic rats was confirmed and the stability of the complex shown to be due to an Amadori rearrangement. The studies also demonstrate the relative specificities of glucose, galactose and mannose in their reaction with collagen. The glycosylation of lysine in vitro occurs with glucose and galactose, but not with mannose, whereas only gucose reacts with hydroxylysine to any significant extent. Glycosylation of collagen occurs slowly during normal aging, but in contrast with reports suggesting accelerated aging of collagen in diabetic animals, we clearly demonstrated that the apparent increased stability is not due to an acceleration of the normal maturation process involving the reducible cross-links.

Animals↗
PubMed1981

Identification of two further collagenous fractions from articular cartilage.

Salt fractionation of pepsin-solubilized human and porcine articular cartilage has revealed the presence of two further collagenous fractions, CF1 and CF2, at high salt concentration following the precipitation of Type-II, 1 alpha, 2 alpha, 3 alpha, and Type-M collagens. Both fractions precipitate at 2.0 M NaCl, but higher yields of CF1 are obtained at 3.0 M NaCl. CF1 and CF2 can be separated in the native form using carboxymethyl-cellulose chromatography. Under denaturing conditions, CF1 has an apparent molecular weight of 25 000 and is unaffected by mercaptoethanol, whereas CF2 has a molecular weight of 35 000 before and 12 000 after reduction by mercaptoethanol. These fractions are probably fragments derived from larger collagen molecules, although the cyanogen bromide digest studies suggest that they are derived from a collagenous type other than one of those previously identified in cartilage.

Amino Acids↗
PubMed1981

Natural family planning IV. The identification of postovulatory infertility.

The estimated time of ovulation (ETO) was correlated with the day of defined postovulatory infertility in 66 hormonally normal menstrual cycles from 24 subjects for each of 15 different natural family planning methodologies. Inherent weaknesses were identified in methods based upon calendar calculations or basal body temperature only. These weaknesses could be removed for the basal body temperature-only methods if symptoms, especially the peak mucus symptom, were added to the temperature records. However, the peak mucus symptom alone had the greatest precision of all methods studied. No advantage could be identified in combining the basal body temperature with the peak symptom.

Adult↗
PubMed1980

Chemical cross-linking restrictions on models for the molecular organization of the collagen fibre.

The nature of the precise packing of collagen molecules into a collagen fibril, producing the characteristic regular banding, is still debatable. The problem has been approached using electron microscopy and X-ray diffraction techniques, and several models have been proposed, including hexagonal packing, an octafibril structure, a two-strand rope and a five-strand rope (for review, see ref. 1). For the past decade the pentafibrillar model, originally proposed by Smith, has been widely accepted as the fundamental building unit. This model, based on the quarter-stagger end-overlap hypothesis of Hodge and Petruska, was supported by the X-ray diffraction data of Miller and Wray. These X-ray data have now been reinterpreted by Hulmes and Miller in terms of a quasi-hexagonal packing of collagen molecules. We argue here that until other characteristic parameters are taken into account, in particular the chemical cross-linking evidence, the packing problem is still unresolved.

Collagen↗
PubMed1980

Studies on the assembly of the rat lens capsule. Biosynthesis of a cross-linked collagenous component of high molecular weight.

1. Intact rat lenses in tissue culture synthesize hydroxy[3H]proline-containing polypeptides of apparent mol.wt. approx. 180000, which become assembled into aggregates of higher molecular weight with time. 2. Both the 180000-mol.wt. species and the aggregates are components of the deoxycholate-insoluble base-membrane matrix. 3. Formation of the high-molecular-weight aggregate is accompanied by the biosynthesis of the reducible hydroxylysine-derived cross-link hydroxylysino-5-oxo-norleucine. 4. Hydroxylysino-5-oxonorleucine and dehydrohydroxylysinonorleucine are the major reducible cross-links present in intact foetal and 1-month-old calf lens capsules.

Animals↗
PubMed1980

Polymeric C-terminal cross-linked material from type-I collagen. A modified method for purification, anomalous behaviour on gel filtration, molecular weight estimation, carbohydrate content and lipid content.

Polymeric cross-linked C-terminal peptide material (poly-alpha 1CB6) from mature bovine tendon type-I collagen was prepared and purified by a modification of the method previously described [Light & Bailey (1980) Biochem. J. 185, 373-381]. Poly-alpha 1CB6 was shown to exhibit concentration-dependent aggregation effects on gel filtration due to interaction with a filtration medium. The material had an amino acid content that was very similar to a mixture of alpha 1CB6 and alpha 1CB5. The material was shown to be polydisperse with a mol.wt. range of 50 000-350 000, but chromatographic fractions were relatively homogeneous over this molecular weight range with respect to amino-acid composition. The heterogeneity of the material was not due to incomplete CNBr peptide cleavage, as poly-alpha 1CB6 did not contain detectable quantities of methionine. The material showed no discrete bands on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis but gave a constant blue stain throughout the molecular weight range described above. Lipid analysis showed that the partially purified material contained elevated levels of stearate when compared to the crude CNBr-digested starting material. This may indicate the specific association of a stearic-acid-rich lipid with the peptide material. On carbohydrate analysis poly-alpha 1CB6 was shown to contain only galactose and glucose at levels of 0.72 and 0.28% respectively. The carbohydrate and amino acid analyses indicated that (alpha 1CB6)2-(alpha 1CB5)1 may be the basic cross-linked structural unit of poly-alpha 1CB6)2-(alpha 1CB5)1 units, although the carbohydrate analysis indicated that the higher molecular weight oligomers may be enriched in alpha 1CB6.

Amino Acids↗