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Biomedical subjects

E C Carlson

Publications and source records attributed to E C Carlson.

At least 73 records · Page 4Linked to original sources
PubMed1975

The development of proline-containing extracellular connective tissue fibrils by chick notochordal epithelium in vitro.

Notochords were isolated from Hamburger-Hamilton stages 13-15 chick embryos by trypsinization and microdissection. These were shown by electron microscopy to be completely devoid of extracellular materials or mesenchymal contaminants. Cultivation of notochordal isolates was carried out on a non-collagenous (Falcon Plastic) substratum for 0 to 48 hours. At 12 hours of in vitro incubation, a discontinuous basal lamina could be demonstrated on the surface of notochordal cells. This was followed by the appearance of microfibrils of various sizes and other components of the extracellular matrix. By 48 hours of in vitro incubation, the same extracellular materials which surround the notochord in vivo (notochord sheath) could be demonstrated in vitro. Autoradiographic studies show that tritiated proline is taken up by notochordal cells and secreted to the extracellular space where label is associated with basal lamina, microfibrils and ground substance. When cis-hydroxyproline, a known collagen-specific inhibitor is added to the system, tritiated proline label is located primarily intracellularly and fewer areas of active fibrillogenesis are noted. This suggests that ultrastructurally recognizable materials produced by notochordal cells in vitro may be at least partially collagenous. Significantly, these materials are produced in vivo at the same time (following stage 10) that notochordal tissues actively induce somite differentiation and cartilage formation. It seems reasonable that a biochemically or ultrastructurally identifiable component of the extracellular matrix may possibly mediate such induction.

Animals↗
PubMed1975

Properties and origins of infectious rhinovirus type 14 particles of different buoyant densities.

Isopycnic centrifugation of rhinovirus type 14 (RV14), purified from infected HeLa or KB cell cultures, into CsCl gradients resolved two bands of infectious virus particles with buoyant density values of 1.409 +/- 0.007 (H virus) and 1.386 +/- 0.004 (L virus) g/ml. Only H virus was detected by incorporation of radiolabeled uridine into viral RNA, and H virus accounted for the majority of infectivity in gradients. H and L virus could not be differentiated by plaque morphology, extent of neutralization by RV14-specific antiserum, or particle size. Electron microscope studies showed that most L-virus particles were associated with an amorphous material. Treatment of L virus with proteolytic enzymes or rebanding L virus in CsCl gradients resulted in recovery of the majority of infectivity as H virus. Virus purified from cell-free fluids from infected HeLa or KB cell cultures banded only as H virus. HeLa cell cultures challenged with purified H virus and harvested at 3 h postinoculation for virus purification yielded only infectious H virus. Both H and L viruses were detected in cell cultures that had been challenged with purified H virus and harvested at 12 h postinoculation. The data suggest that H virus represents progeny virus, whereas L virus represents sequestered infectious virus particles which become associated with an amorphous material and do not enter into viral replicative processes.

Adsorption↗
PubMed1975

Presence of modified fibroblasts in ischemic contracture of the intrinsic musculature of the hand.

Biopsies of fibrotic interosseous muscles were obtained from three patients with ischemic contracture of the intrinsic muscles of the hand. Control biopsies were taken from normal contralateral interossei and from normal interossei crushed three weeks earlier. Examination of the specimens from the affected muscles under the electron microscope demonstrated large numbers of modified fibroblasts with ultrastructural features of both fibroblasts and smooth muscle cells. The atypical fibroblasts observed resembled myofibroblasts seen in contracting wounds, Dupuytren's contracture, stenosing tenosynovitis, and idiopathic carpel tunnel syndrome. Biopsies from normal muscle and crushed normal muscle contained normal fibroblasts and smooth muscle cells but no modified fibroblasts. Active contraction of modified fibroblasts could be responsible for progressive muscle shortening seen in intrinsic contracture.

Adolescent↗