Brucellosis of the sacro-iliac joint.
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Aged↗
Biomedical subjects
J E Scott
Publications and source records attributed to J E Scott.
Alveolar pre-type II cells from the fetal rabbit lung: effect of confluence on the production of disaturated phosphatidylcholine.
Pre-type II alveolar cells isolated from the fetal rabbit lung on the 24th gestational day have been maintained in vitro for 14 days in a chemically defined medium supplemented with hormone-stripped serum. These cells replicate in culture. Measurement of the incorporation of [14C]choline into cellular disaturated phospholipid indicated that those cells grown in vitro under standard conditions for 8 days (pre-confluent) incorporate the radioactive precursor at a similar rate to cells maintained for 14 days (post-confluent). Both dexamethasone and serum-free medium conditioned by monolayer cultures of fetal rabbit lung fibroblasts stimulated [14C]choline incorporation into disaturated phosphatidylcholine (PC) by the pre- and post-confluent cultures after 24 or 48 h of exposure: the conditioned medium was more effective than the steroid. These treatments had little effect on choline incorporation into disaturated phosphatidylcholine of preconfluent cells during the first 12 h. A marked response occurred by 24 h after which the labelling of disaturated phosphatidylcholine plateaued. In contrast, with post-confluent cells labelling of disaturated PC increased in a more linear fashion and only plateaued after 72 h. Determination of the ratio of incorporation of [14C]choline into disaturated versus unsaturated phospholipid indicated that serum-free medium conditioned by monolayer cultures of fetal lung fibroblasts specifically increased the level of radioactive precursor in the disaturated phospholipid in both the pre- and post-confluent cell monolayers.
Animals↗
Proteoglycan-collagen interactions.
Among the most important events in connective tissue physiology are the nucleation, growth and calcification of collagen fibrils. It has been speculated that all are associated with, or even controlled by collagen-proteoglycan interactions. We therefore developed methods for investigating these associations in tissues, particularly for understanding their significance for type I collagen, the commonest form of collagen in the body, especially predominant in bone. Using an electron-dense dye, Cupromeronic blue, in the 'critical electrolyte concentration' mode, and digestion by hyaluronidase, chondroitinase ABC or keratanase, supported by biochemical analyses, we found that dermatan sulphate proteoglycan of soft connective tissue (skin, tendon, cornea) was regularly and orthogonally arrayed at the fibril surface, at the d or e band. Keratan sulphate proteoglycan in the cornea associates orthogonally at the a and c bands. Bone, demineralized by a non-aqueous technique which retains proteoglycans in the tissue, does not contain orthogonal arrays; the interfibrillar proteoglycan filaments are oriented parallel to the fibril axis. The main proteoglycan in bone is chondroitin sulphate-rich. There are thus four separate specific binding sites on type I collagen fibrils, each one associating with one particular proteoglycan, and apparently no other. This implies that there are two corresponding binding sites in each proteoglycan. Available evidence shows that there are two species of small dermatan sulphate and keratan sulphate proteoglycans. It is suggested that each species is specific for its own band (a, c, d or e). Hyaluronate and chondroitin sulphate are probably mainly interfibrillar, acting in a space-filling capacity.
Animals↗
Proteoglycan-collagen interactions in intervertebral disc. A chondroitin sulphate proteoglycan associates with collagen fibrils in rabbit annulus fibrosus at the d-e bands.
Rabbit annulus fibrosus and nucleus pulposus were analysed for hydroxyproline, chondroitin sulphate, keratan sulphate and dermatan sulphate. Tissue proteoglycans were stained for electron microscopy with Cupromeronic blue, used in the critical electrolyte concentration mode, with and without prior digestion by chondroitinase AC or ABC, hyaluronidase or keratanase. Collagen bands, a-e were demonstrated with UO2++. A chondroitin sulphate proteoglycan was found orthogonally associated with loosely packed collagen fibrils in annulus fibrosus at the d and e bands. The close metabolic and structural analogies with the dermatan sulphate proteoglycans previously shown to be located at collagen d-e bands in tendon, skin, etc. (Scott and Haigh (1985) Biosci. Rep. 5:71-81), are discussed. Tightly packed annulus collagen fibrils were surrounded by axially oriented proteoglycan filaments, mostly without specific locations.
Animals↗
DNA sequence of the major capsid protein gene of herpes simplex virus type 1.
The DNA sequence of the region of the herpes simplex virus type 1 genome encoding the major capsid protein was determined. The predicted protein contains 1374 amino acid residues and has a molecular weight of 149,075. Comparisons of the amino acid sequence of this protein with those predicted from the published DNA sequences of two other herpesviruses, varicella-zoster virus and Epstein-Barr virus, resulted in the identification of the major capsid protein gene in each genome.
Amino Acid Sequence↗
The complete DNA sequence of varicella-zoster virus.
The entire DNA sequence of varicella-zoster virus (VZV) was determined using the M13-dideoxynucleotide technology. The genome is variable in size, but the sequence which was obtained comprises 124884 bp. Analysis of the sequence indicated that the genome contains 70 genes distributed about equally between the two DNA strands. The genes are organized compactly, but regions of overlap between protein-coding regions are not extensive. Many of the genes are arranged in 3'-coterminal families, and at least one is spliced. The discerned organization of VZV genes and that deduced for herpes simplex virus type 1 (HSV-1) from published transcript mapping data indicate that these two members of the Alphaherpesvirinae are very similar in gene layout. Comparisons of the predicted amino acid sequences of VZV proteins with those available for HSV-1 proteins generally suggest evolution from an ancestral genome, and allow the functions of several VZV genes to be deduced, although limited regions where the genomes differ in functional organization were also identified.
Amino Acid Sequence↗
Acute focal bacterial nephritis.
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Adolescent↗
Proteoglycan-collagen relationships in developing chick and bovine tendons. Influence of the physiological environment.
Developing and mature flexor digitorum tendons of chick and bovine origin were analyzed for nucleic acid, hydroxyproline, hyaluronate, chondroitin sulfate and sulfated glycosaminoglycan hexuronate. Collagen fibril diameters were determined by electron microscopy. Results are compared with similar data from rat tail tendon. Tissue hydroxyproline (mg/g) increased rapidly in early embryogenesis, while collagen fibril diameters remained relatively constant and small. Hyaluronate and chondroitin sulfate were present in considerable quantities, (phase I). A rapid increase in fibril diameters in midterm 'pregnancy' coincided with a decrease in hyaluronate and chondroitin sulfate contents (phase II). The transition from phase I to phase II was associated with the first loading by active muscles of the tendon, independently of whether the animal was pre- or post partum. The probable existence of a developmental program intrinsic to tendon itself, is discussed. The data are compared with predictions from three different simple models. Hyaluronate is concluded to be entirely interfibrillar, chondroitin sulfate is probably similarly distributed, whereas dermatan sulfate is entirely fibril-surface associated. The 'small' dermatan sulfate proteoglycan is assigned to the 'd' band in the gap zone.
Animals↗
A method of processing tissue sections for staining with cu-promeronic blue and other dyes, using CEC techniques, for light and electron microscopy.
The application to connective tissues etc. of new histochemical and ultrastructural methods involving consecutive treatment with dye-salt baths, specific enzymes, antibodies and decalcifying fluids, is best carried out on sections on glass slides. This ensures uniform access of reagents to substrates and allows the accurate monitoring of the results, as well as exploiting the strengths of the newer reagents (e.g. Cupromeronic Blue) in that they are highly coloured as well as electron dense. However, very high losses of connective tissue sections usually occur in the various solutions, to the extent that many important investigations are rendered almost impossible because of the high cost of the reagents. We describe a technique which we use routinely, that gives very high recovery of sections of "difficult" tissues from multi-stage enzyme and stain treatments, for light microscopy followed by plastic embedding of the coloured sections for electron microscopy.
Animals↗
Hydatid disease of the cervical spine.
Hydatid disease affecting the cervical spine occurred in a 31-year-old man. Because bone grafting is associated with a high failure rate, treatment included filling the excised defect with a high-density polyethylene implant and fusing the cervical spine to stabilize it.
Adult↗
Proteoglycan-type I collagen fibril interactions in bone and non-calcifying connective tissues.
The association of proteoglycans with type I collagen fibrils in skin, tendon, cornea and bone has been determined by electron microscopy using an electron-dense dye, Cupromeronic blue, in the critical electrolyte concentration mode, backed up by biochemical analysis and digestion by hyaluronidase or keratanase. A major proteoglycan of the soft tissues, containing dermatan sulphate, is shown to be regularly and orthogonally arranged at the surface of the fibrils. Uranyl acetate counterstaining revealed that the main specific binding site is the 'd' band, which previous work indicated is very close to the initial site of calcification of type I collagen fibrils. Bone, demineralized by a 'non-aqueous' technique which preserves the proteoglycan in the tissue, does not contain orthogonal arrays; the interfibrillar proteoglycan filaments are oriented parallel to the fibril axis. The main proteoglycan in bone is chondroitin sulphate-rich. It is suggested that dermatan sulphate proteoglycan plays a role in preventing soft connective tissues from calcifying.
Animals↗
'Small'-proteoglycan:collagen interactions: keratan sulphate proteoglycan associates with rabbit corneal collagen fibrils at the 'a' and 'c' bands.
Proteoglycans (PGs) in rabbit corneal stroma and mouse sclera have been stained for electron microscopy with Cupromeronic blue in a critical electrolyte concentration (CEC) mode, with and without prior digestion of the tissue by keratanase or chondroitinase ABC to remove the keratan sulphate (KS) or chondroitin-dermatan sulphates (CS or DS) respectively. Two classes of PGs, located orthogonally to the corneal collagen fibrils at either the 'step' (band 'a' or 'c') or gap zone (band 'd' or 'e') are shown to be KS-PGs or DS-PGs respectively. Four separate and specific PG binding sites on Type I collagen fibrils have thus been identified. Rabbit corneal KS and DS PGs each contain two kinds of PG (Gregory JD, Coster L & Damle SP (1982) J. Biol. Chem. 257, 6965-6970). We propose that each 'small' protein-rich PG is associated with a specific binding site on the collagen fibril.
Animals↗
Proteoglycan histochemistry--a valuable tool for connective tissue biochemists.
The histochemistry of connective tissue proteoglycans (PGs) poses two major requirements, 1. for the specific demonstration of a given PG and, 2. at the ultrastructural level, for the examination of the shape of the PG, and its interactions with other molecules and tissue elements. Techniques for the localisation and identification of PGs are discussed, according to the principles behind their application. The strengths and weaknesses of antibody stains are compared with those of mini-molecular reagents, based on resolution, sensitivity, stoichiometry and tissue penetration. The concept of specificity is analysed in this context. The polyanionic characteristics of PGs are exploited to allow very sensitive detection and localisation by cationic probes, both macro- and mini-molecular. Complex formation by heavy metal cations, basic dyestuffs and polycations with PGs is a simple ion-exchange process (basophilia), which can be manipulated to give considerable specificity, e.g. using the critical electrolyte concentration (CEC) concept. The fundamental physical chemical unity of the phenomena of basophilia, CEC and biochemical fractionations of tissue polyanions by anion-exchange is discussed. This unity allows direct quantitative and qualitative comparisons to be made between histochemical and biochemical results at all levels from the tissue sample to the single molecule of PG in situ. The great value of the partnership between microscopy and analytical biochemistry is emphasised. The expanded solution domain of PGs collapses during formation and processing of the 'stained' complex, obscuring molecular detail and possibly resulting in translocation of the PG. Approaches aimed at restoring the initial situation, and their application to electron microscopy of PGs in tissues are outlined. Complexes of PG with ambient polycations may form, either as artefacts during processing or as an integral part of in vivo ultrastructure. Uptake of stain may be partly or totally blocked, in consequence. Ways of investigating, avoiding, or making use of this phenomenon are described. Application of integrated approaches to the study of PG--collagen and PG--elastin interactions in tissues are discussed. Specific interactions and stoichiometric relationship, particularly of dermatan sulphate proteoglycans with type I collagen have been observed, in skin, tendon, and other non-calcifying tissue, but not in bone.
Animals↗
DNA sequence of the major inverted repeat in the varicella-zoster virus genome.
The major inverted repeat of 7319.5 base pairs is present at an internal site in the varicella-zoster virus genome and at one terminus. A DNA sequence of 7747 base pairs containing the repeat was determined and analysed. The G + C content of the repeat is not uniform, and is significantly higher than that of adjacent unique regions. The repeat contains a G + C-rich reiterated sequence, an A + T-rich sequence with the potential of forming a hairpin structure which may form part of an origin of DNA replication, and three open reading frames predicted to encode primary translation products with approximate molecular weights of 140 000, 30 000 and 20 000. The possibility is discussed that the expression of other open reading frames near the genome termini may depend upon genome conformation.
Amino Acid Sequence↗
An X-ray diffraction analysis of rat tail tendons treated with Cupromeronic Blue.
Cupromeronic Blue was used to stain selectively the proteoglycans in rat tail tendons under 'critical electrolyte' conditions. Earlier electron microscopical observations indicated that at least one type of proteoglycan filament is associated with tendon collagen fibrils at the positive staining band 'd'. To ensure that this was not an artefact caused by specimen preparation or the subsequent positive staining of the collagen fibrils, we have analysed low angle meridional diffraction patterns from stained but not dehydrated, embedded or counterstained tissues. Axial electron density profiles of Cupromeronic Blue-stained compared with unstained rat tail tendons revealed the axial locations and relative amounts of dye in both mature and young wet specimens. In mature tendons, the difference electron density profile contained a broad peak centred near residue 180 along the 234-residue D-period. This corresponds to the electron-optical staining band 'd'. In young tendons a similar distribution of stain was observed although in this case there was evidence of a doublet of peaks, one centred near residue 182 (band 'd') and the other near residue 165 (midway between bands d and e1). The wet proteoglycan--Cupromeronic Blue complexes distribute over about 30 nm along the collagen fibril axis. Comparison with the images of filaments seen in the electron microscope suggests that the dye complexes collapse significantly on dehydration and embedding.
Aging↗
HLA antigens in Hirschsprung's disease.
In 55 children with Hirschsprung's disease, 64 of their normal siblings and 120 other members of their families, HLA-A, B and C types were examined. The statistical significance of the raised incidence of A1, B14, B37 and Bw35 in the patients disappeared after correction for multiple testing. The levels of homozygosity were very similar in patients and normal controls. The results indicate no direct association of the disease with HLA type.
Child↗
Management of congenital posterior urethral valves.
A series of 46 children treated by the author since January 1972 for congenital posterior urethral valves is presented: 22% were diagnosed at birth, 28% as neonates and 52% in the first 3 months of life. Ninety-three per cent had unilateral or bilateral dilatation of the upper urinary tract at the time the valves were diagnosed and 72% had ureteric reflux. Unilateral reflux occurred into the left ureter twice as often as the right. Renal failure was present at the time of diagnosis in 72% of all of the children but in 83% of those aged less than 3 months. Surface urinary diversion was used minimally during post-operative management and contributed little to the recovery of renal function. Reflux disappeared spontaneously in one-third of the refluxing ureters. Ureteric dilatation subsided spontaneously in 57% of dilated ureters. Surgery was performed mostly for reflux. Non-refluxing ureteric dilatation was made worse by surgery in a few instances and in others the dilatation improved with time rather than as a result of surgery. Renal function returned to normal in over 60% of the children who were in renal failure at diagnosis. Measurement of glomerular filtration rate was the most accurate method of predicting recovery of renal function: a value of less than 50% of normal for age at the time of diagnosis forecast persistent chronic renal failure with all its attendant complications.
Child↗
Secondary structure of hyaluronate in solution. A 1H-n.m.r. investigation at 300 and 500 MHz in [2H6]dimethyl sulphoxide solution.
The 1H-n.m.r. spectra of solutions in [2H6]dimethyl sulphoxide of the sodium salts of tetra-, hexa- and octa-saccharides prepared from hyaluronate by testicular-hyaluronidase digestion were examined at 300 and 500 MHz. The signals from hydroxy groups at positions 2 and 3 in the glucuronic acid moiety were assigned. Their chemical shifts and associated temperature-dependencies, as well as their coupling constants, depended on whether or not the uronic acid was at the non-reducing end. Deviations from the 'normal' pattern of hydroxy-group proton n.m.r. behaviour were attributable to participation in hydrogen bonds, either to the acetamido carbonyl oxygen atom or the pyranose ring oxygen atom of neighbouring N-acetylhexosamine moieties. A secondary structure, containing four different hydrogen bonds per trisaccharide unit of glucuronsyl-hexosaminyl-glucuronic acid, was demonstrated. This is the first complete and detailed secondary structure to be established for hyaluronate in any solvent. Hyaluronate is compared with chondroitin sulphate, dermatan sulphate, heparan sulphate and keratan sulphate in their potential to form secondary structures with features in common. The significance of the details of the structure to its overall stability, and the probability of their persistence into aqueous environments, are discussed. The presence of all or most of the secondary structure in glycosaminoglycuronans is correlated with a space-filling function in the tissue, and with a high carbohydrate content in the parent proteoglycan in the case of the chondroitin sulphates.
Carbohydrate Conformation↗