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Biomedical subjects

J Wakely

Publications and source records attributed to J Wakely.

At least 19 recordsLinked to original sources

Possible case of spondylo-epiphyseal dysplasia in a medieval skeleton.

Multiple anomalies of vertebral and long bone growth were observed in the incomplete skeleton of an adult male from a collection of 693 medieval skeletons excavated at Abingdon, Oxfordshire. The skeleton consists of a fragmented skull, right scapula and humerus, left humerus, radius, ulna and partial hand, vertebrae from C1 to T11, and fragments of the ribs and sternum. The bones were examined, measured, and radiographed. The humeri are abnormally short and thick, with exaggerated muscle attachments. Both shoulder joints show extensive osteoarthritic destruction. Some vertebrae show slight flattening of the bodies, and there is possible evidence of both kyphosis and scoliosis. Skull, forearm, and hand bones are of normal size and morphology. Lack of lower limb bones and abnormal proportions in the upper limbs prevent meaningful estimation of stature. However, the other features of the skeleton are consistent with a diagnosis of spondylo-epiphyseal dysplasia. No other skeletons displaying similar anomalies were observed.

Arm↗

Medieval example of metastatic carcinoma: a dry bone, radiological, and SEM study.

An elderly male skeleton from medieval Canterbury displayed evidence of DISH and metastatic carcinoma. The dry bone findings, SEM, and radiography suggest a primary focus in the prostate. A review of the palaeopathological literature has shown that such a finding is extremely rare in archaeological remains. This is the first reported case of prostatic carcinoma from medieval England.

Bone Neoplasms↗

Changes in the surface morphology of lens fibres in the developing chick eye in relation to lens transparency.

The surface morphology of chick lens fibres and epithelium was studied by scanning electron microscopy at several stages of embryonic development. In common with many species of adult lens, the embryonic fibres possessed a remarkable array of interlocking devices which were present from an early stage of development. The primary and secondary fibres both acquired projections during the maturation process, although the types of interlocking devices were different in the two populations. Immediately after obliteration of the lens vesicle, 'flap' or 'finger-like' projections were seen on the primary fibres, and these increased in number during development. A pronounced change in the morphology of the primary fibres was seen between Stages 35 and 38 with the formation of large irregular, interlocking processes. Secondary fibre maturation resulted in a complex but well defined joining apparatus with 'mounds and hollows', 'finger', 'flap' and 'ball-like' projections being formed. Transmission electron microscope grids placed beneath the lenses allowed a direct assessment of lens transparency during development. In the early stages, the lens appeared opaque, uniform transparency becoming apparent between 6-7.5 days of incubation. No specific correlations between the morphology of the lens fibres and the degree of transparency were found, although the size of extracellular spaces appeared to be important, close packing of fibres being generally associated with transparency.

Animals↗

Scanning electron microscopical and histochemical study of the endoderm in the early chick embryo.

The endoderm of gastrulating chick embryos shows regional variations in cell shape and size. These were studied by scanning electron microscopy, histochemistry and immunofluorescence. Particular attention was given to the distribution of the cytoskeleton. Four zones of differing morphology were observed. The changing size and shape of these zones could be correlated with the entry of the definitive endoblast through the primitive streak, displacing existing primary hypoblast to the edges of the area pellucida. Endodermal cells were shown to have a well organised cytoskeleton. The cytoskeletons of individual cells were linked to give a cytoskeletal network extending across the endoderm as a whole.

Animals↗

Immediate effects of procaine and pentobarbital on placodal and non-placodal head ectoderm of the chick embryo in vitro.

The effects of procaine and pentobarbital on lens placodes, otic placodes and non-placodal head ectoderm of the chick embryo in vitro have been examined by scanning and transmission electron microscopy. Both types of placode cells were less sensitive to both drugs than non-placodal cells. Cellular responses to pentobarbital were microvilli formation, reduction in cetylpyridinium chloride-stainable surface coat and epithelial dissociation with thinning of the basement membrane. Procaine treatment induced the formation of large cytoplasmic blebs and cytoskeletal condensations but did not affect the surface coat. Examination of head ectoderm appears to be of value in the evaluation and comparison of drug effects on differentiating tissues. Anaesthetics also form useful probes for structural and functional changes in the cells of such developing systems.

Animals↗

Observations on the role of ectodermal spreading in the early stages of lens placode invagination in the chick embryo.

The importance of differential epithelial spreading in the early stages of chick lens placode invagination in the chick has been demonstrated experimentally in two ways. Generalized swelling of the head caused by immersion in 50% ethanol and restricting the freedom of ectoderm in the eye region to spread by means of ligatures produce both precocious and exaggerated invagination. Inequality of spreading between the placode and surrounding ectoderm in normal development is caused by the adhesion of the former to the optic vesicle, while the ectoderm is free to spread and move over underlying tissues. Folds, i.e. invaginations, form at the boundary between the placode and its surroundings.

Animals↗

The ultrastructure of polygonal networks in chick embryonic cells in vitro.

Polygonal networks in cultured chick endoderm cells are ordered arrays of actin microfilaments situated just beneath the dorsal cell surface. Each strut is formed from a bundle of microfilaments and 5-7 bundles intersect at each node. Dense bodies are seen in nodes and some struts. At its periphery the network is attached to the substrate at the termini of long radial struts. Most of the network is resistant to detergent extraction. Sliding microfilaments can explain the observed behaviour of networks in live cells.

Animals↗

Organization of actin filaments in early chick embryo ectoderm: an ultrastructural and immunocytochemical study.

By combining transmission electron microscopy (TEM), scanning electron microscopy (SEM) and immunocytochemistry at both light and TEM levels the organization of actin in early chick ectoderm has been demonstrated. Every cell is encircled by a ring of actin filaments which are associated with apically situated intercellular junctions. In this way the actin ring of each individual cell is connected to that of surrounding cells and a continuous network is formed. As clearly shown by immunofluorescence and SEM studies on intact and Triton X-100 treated whole-mount preparations this network extends throughout the entire layer, interrupted only at the blastoderm margins and the primitive streak. A more diffuse arrangement was sometimes seen at cell bases. It is suggested that the network extending throughout the ectoderm gives it stability and cohesion and is important in gross morphogenetic movements involving the entire layer. The less-organized arrangement at cell bases is associated more with movements of individual cells.

Actins↗

Morphogenesis of human placental chorionic villi: cytoskeletal, syncytioskeletal and extracellular matrix proteins.

Immunocytochemical and ultrastructural methods were used to investigate the distribution of a family of structural proteins in the human placenta near term. These reveal the distribution of cytoskeletal and 'syncytioskeletal' components that may account for some of the more obvious micromorphological features of placental structure. In the syncytiotrophoblast a potentially supporting structure 'the syncytioskeletal layer' is described. It is an apparently continuous and complex polymeric network covering the villous tree, a surface of the order of 10 m2 in area in the full term placenta (Aherne & Dunnill 1966). It is suggested that this layer plays a part in morphogenesis of the villous tree.

Chorionic Villi↗

Propidium iodide as a nuclear marker in immunofluorescence. I. Use with tissue and cytoskeleton studies.

Some examples are given of immunofluorescence with tissue sections and microtubular cytoskeletons of cultured cells where the fluorescent dye propidium iodide (PI) has been used as marker of nuclei. The emission wave length of IP is longer than that of fluorescein, making it possible to use several different and commonly available filter combinations. The use of nuclei as positional indicators is often a more suitable method than phase microscopy combined with immunofluorescence because of low background illumination against which morphology is viewed, circumventing the need for often expensive phase optics.

Antibodies↗

Scanning electron microscopy of wound healing in Xenopus and chicken embryos.

Wound closure in the ectoderm of Xenopus early neurulae and chick primitive-streak embryos has been studied by scanning electron microscopy (SEM). Initial gaping of the wound and a cobble-stone appearance of cells peripheral to the wound in both Xenopus and chick confirm that the ectoderm is under lateral tension at these stages. Healing is rapid: in Xenopus embryos wound closure has started within 5 min of wounding; in chick healing is almost complete within 30 min in some cases. The SEM observations suggest that in Xenopus embryos changes in cell shape are the major mechanism for wound closure. In chick embryos wound healing is also accompanied by changes in the shape of the marginal cells, but evidence is presented that in this system cell proliferation is important. The mechanisms of wound healing in Xenopus and chick embryonic ectoderm are compared with those of wound healing in other tissues.

Animals↗

Differentiated regions of human placental cell surface associated with attachment of chorionic villi, phagocytosis of maternal erythrocytes and syncytiotrophoblast repair.

Scanning electron micrographs of human placental cell surface show: (1) Differentiated zones of trophoblast which may be covered by fewer 'microvilli' than the adjacent syncytial cell surface and which extend as a narrow, usually distal protrusion of the chorionic villus. This narrow outgrowth terminates as a fractured end. Presumably since preparations were obtained from therapeutic terminations of pregnancy or Caesarian deliveries these broken ends represent the yield point in the anchoring 'villi' ruptured as a result of surgery. Similar anchoring 'villi' with fractured ends were observed in unfixed material with the use of Nomarski interference contrast microscopy. (2) It appears that, during apparent phagocytic uptake of maternal erythrocytes by syncytiotrophoblast, cell surface lining the forming vacuole still retains an irregular microvillous surface. This observation indicates the potential location of phagocytosis receptors for red blood cells in the placental cell surface. (3) Areas of human placenta which appears to have been damaged and may be undergoing repair exhibit masses of cells with conspicuous microvillar cell surfaces. The origin of these cells is discussed in relation to the usual processes of syncytiotrophoblast formation.

Cell Membrane↗

Evidence for changes in cell shape from a 2-dimensional to a 3-dimensional substrate.

Chick embryo mesoderm cells were explanted to culture systems in vivo and in vitro and their subsequent movements were correlated with the external morphology as studied by SEM. In vitro cell movements are exaggerations of normal in vivo movements where a 2-dimensional substrate is encountered rather than a 3-dimensional environment.

Animals↗