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Biomedical subjects

S Humphreys

Publications and source records attributed to S Humphreys.

65 records · Page 4Linked to original sources
PubMed1976

Collagenous and other organizations in mature annelid cuticle and epidermis.

The mature annelid cuticle contains orthogonally oriented collagen in a matrix capped superficially by a dense epicuticle with external corpuscles. The underlying epidermis is a simple columnar epithelium with two major cell types, mucous-secreting cells which secrete through channels in the cuticle to the exterior of the worm, and "supportive" cells which presumably produce and increase the cuticle by secreting into it. The structures of supportive cells, previously interpreted as specialized for establishing interfibrillar collagen order, are revealed by glutaraldehyde fixation as common cellular components without the qualities deemed useful to align collagen. Cell processes which penetrate and sometimes pass completely through the cuticle are not stable, not in geometric order, and lack cilia-like structure. Cilia, unlike the ubiquitous cellular processes, are highly restricted to regions of the epidermis with specialized functions. Cellular control, or other control, of collagen fibrillogenesis remains unestablished.

Animals↗
PubMed1976

Collagen deposition on a preformed grid.

Appearance of collagen fibrils in the cuticle was seen by electron microscopy to be preceded by formation of a finely filamentous matrix material. At first, the fine filaments of the matrix are unorganized. However, signs of orthogonal ordering soon appear in the most superficial portion of the cuticle, and subsequently appear more basally and closer to the underlying epidermis. Meanwhile, fibrils of different staining properties and identifiable as collagen begin to be deposited in the superficial portion of the cuticle, the same region which first showed organized fine filaments. Then, like the fine filaments before them, the collagen fibrils polymerize more basally. Collagen appears to polymerize on the preformed skeleton of fine filaments as though the fine filaments lagen fibrils seems to require direct cellular intervention but occur first in that portion of the cuticle which is furthest away from the underlying epidermis. The fine filaments may be self ordering, extracellular macromolecules which in turn determine the polymerization of collagen fibrils.

Animals↗
PubMed1969

In vitro differentiation of a mouse neuroblastoma.

Mouse tumor C1300 has been established in tissue culture. The cells have a round cell morphology in both the subcutaneous tumor and in suspension culture. However, when given a surface on which to attach, they send out processes up to 3 mm in length and assume the morphology of mature neurons. The attached cells are stained by the Bodian silver procedure for neurons, whereas the cells grown in suspension are not. Electron microscopy reveals that the attached cells contain neurofilaments, neurotubules, and densecore vesicles indicative of nerve fibers. Both free-floating and attached cells have tyrosine hydroxylase activity characteristic of sympathetic nervous tissue. Apparently cell attachment can induce morphological differentiation from an anaplastic round cell to a cell which has many properties of a mature neuron.

Animals↗
PubMedDate not supplied

Congenital amaurotic idiocy--a pathological, histochemical, biochemical and ultrastructural study.

A case of congenital amaurotic idiocy, a subgroup of the neurovisceral lipidoses, is described. This is a rare condition of which only five cases have been reported previously. The brain was small and firm with marked neuronal loss and gliosis. Granular material with histochemical properties of the ceroid-lipofuscin group of lipopigments was found deposited within astrocytes, macrophages and residual brain stem neurons. Cells of the mononuclear phagocyte system within the liver, spleen, thymus and lungs contained similar material. Ultrastructurally this substance appeared as intracytoplasmic membranous and granular deposits within limiting membranes, and biochemical analysis of formalin-fixed tissue did not identify a specific material. Comparison is made with the Batten group of disorders.

Astrocytes↗
PubMedDate not supplied

Thoracic splenosis. Diagnosis of a case by fine needle aspiration cytology.

Fine needle aspiration cytology was used to study chest wall nodules in a patient who presented with fever, cough, pleuritic chest pain and cytomegalovirus infection and who had a previous history of abdominal trauma. The finding of splenic red pulp and white pulp in the aspirate, combined with the results of a radionucleotide liver-spleen scan, led to a diagnosis of thoracic splenosis, a relatively rare condition. Splenosis is thought to result from transplantation of splenic tissue after trauma and may provide some added protection against certain infectious conditions, both of which were present in this case.

Biopsy, Needle↗