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Biomedical subjects

J W Fox

Publications and source records attributed to J W Fox.

At least 127 records · Page 7Linked to original sources
PubMed1980

Characterization of the collagenous domain of bovine glomerular basement membrane.

Bovine glomerular basement membrane was subjected to limited pepsin digestion and the solubilized collagenous polypeptides were characterized. Several electrophoresis systems were used which enabled an examination over a molecular weight range from 20,000 to greater than 10(6). A 0.1% SDS-5% polyacrylamide gel system resolves the reduced digestion product into 17 polypeptides ranging in molecular weight from 78,000 to 340,000. The larger collagenous components were resolved on a 0.1% SDS-2.5% agarose gel system. The nonreduced digestion product resolves into 13 components which vary in molecular weight from 85,000 to 5 million. Upon reduction, the majority of this material is converted to a 165,000 molecular weight component(s) and cross-linked (aldehyde derived) multimers of this component(s) containing as many as 6 cross-linked monomers. The digestion product was subjected to a second pepsin digestion after reduction and alkylation under nondenaturing conditions. This results in a conversion of a larger polypeptides to three lower molecular weight peptides, two of which exhibit an electrophoretic migration identical to alpha 1- and alpha 2-chains of collagen. The results indicate that the collagenous domain of glomerular basement membrane consists of various size collagen molecules connected by disulfide bonds and aldehyde-derived cross-links to form high molecular weight aggregates containing as many as 30 of these polypeptides, and that the larger collagenous polypeptides contain alpha-size segments within their structure.

Animals↗
PubMed1979

The hydrodynamic shape, conformation, and molecular model of Escherichia coli ribosomal 5 S RNA.

The structure of ribosomal 5 S RNA has been examined using several physical biochemical techniques. Hydrodynamic measurements yield a s020,omega and [eta] of 5.5 x 10(-13) x and 6.9 ml/g, respectively. Other parameters calculated from these values indicate the shape of 5 S RNA is consistent with that of a prolate ellipsoid 160 A in length and 32 A wide. Sedimentation equilibrium results show that 5 S RNA exists as a monomer in the reconstitution buffer with an apparent molecular weight of 44,000. Ultraviolet absorption difference spectra show that approximately 75% of the bases in 5 S RNA are involved in base pairing, and of these base pairs 70% are G-C and 30% are A-U. These results on the overall shape and secondary structure of 5 S RNA have been incorporated with the results of other investigators as to the possible location of single-stranded and double-stranded helical regions, and a molecular model for 5 S RNA is proposed. The molecular model consists of three double helices in the shape of a prolate ellipsoid, with two of the double helical regions at one end of the molecule. The structure is consistent with the available data on the structure and function of 5 S RNA and bears similarity to the molecular model proposed by Osterberg et al. ((1976) Eur. J. Biochem. 68, 481-487) based on small angle x-ray scattering results and the secondary structure proposed by Madison ((1968) Annu. Rev. Biochem. 37, 131-148).

Escherichia coli↗
PubMed1978

Structural changes of ribosome by the action of ethylene glycol.

The denaturation of ribosome and RNA by ethylene glycol (EG) has been studied in an attempt to further understand the conformation and stability of the ribosome. At high concentrations of EG, the ribosome, its subunits, and 16S RNA undergo drastic structural changes as shown by circular dichroism, ultraviolet absorption spectroscopy, and sedimentation velocity. Two separate conformational transitions were observed for the 30S subunit; one from 30 to 50% EG and another from 60 to 90% EG. This observation suggests the presence of two "domains" in the 30S subunit which differ in their stability. However, the 50S subunit undergoes a single sharp transition at 60 to 90% EG, consistent with the notion of a highly cooperative conformation. Association of the subunits stablizes part of the 30S subunit since the transition curve for the 70S ribosome does not exhibit significant change at the low EG concentration region as seen for the 30S subunit. Removal of proteins from the 30S subunit broadens the transition curve to lower EG concentrations and suggests the role of proteins in stabilizing the conformation of the 16S RNA.

Cell Fractionation↗
PubMed1978

Changes in the conformation and stability of 5 S RNA upon the binding of ribosomal proteins.

The binding of ribosomal proteins L25, L18, and L5 to 5 S RNA results in a conformational change and a destabilization of the 5 S RNA molecule. The changes observed in the near ultraviolet circular dichroism (CD) spectra and in the melting profiles indicate an increase in base stacking uith an accompanying increase in asymmetry of the bases and a decrease in the conformational stability of the 5 S RNA. These results are consistent with the interpretation that the binding of these proteins increases the stacking of specific single-stranded bases in 5 S RNA and aligns them in helical arrays, resulting in a conformation which facilitates base-pairing with nucleotide segment(s) of the ribosomal 23 S RNA or the transfer RNA (or both). The simple and precise difference CD method described here is potentially useful for studying subtle conformational changes of other nucleic acid-protein interactions.

Bacterial Proteins↗
PubMed1977

Nonoperative management of fingertip pulp amputation by occlusive dressings.

Nonoperative management of fingertip pulp amputations has been employed in eighteen adults. After wound cleansing and debridement, the wound was covered by an occlusive dressing. Healing of the amputated fingertip occurred within four weeks. The healed fingertip had an excellent sensory perception, normal range of motion and an acceptable cosmetic appearance. This satisfactory outcome was realized with less than ten days lost from work.

Aluminum↗
PubMed1977

An adjunct to mammoplasty: the pectoral muscle flap.

The pectoralis major muscle has overcome many of the complications of augmentation mammoplasty after subcutaneous mastectomy. It places the implant deep to prevent skin slough and irregularities in skin surface contour. The flap eliminates abnormal implant posture when the pectoralis major is contracted. The short (5 to 7 days) staging of the procedure allows sealing of the pocket from external innoculation of bacteria while preventing unretrievable skin and nipple shrinkage.

Breast↗
PubMed1976

Emergency tracheostomy.

On rare occasions, emergency tracheostomy is indicated to establish an airway. Using a large bore needle as a guide, tracheal intubation is assured with minimal damage to vital structures in the neck.

Airway Obstruction↗
PubMed1976

The use of drains in subcutaneous surgical procedures.

Continuous suction, negative pressure drains serve as an excellent "atmospheric bandage" in subcutaneous surgical procedures while helping to expedite wound healing and impede complications secondary to tissue plane dissection.

Dermatologic Surgical Procedures↗
PubMed1976

Contiguous cervical and deltopectoral flaps for skin lining and replacement with en bloc resection of cancer of the head and neck.

Contiguous cervical and deltopectoral flaps have several advantages in reconstruction of the head and neck after extirpation of cancer. The cervical skin provides an excellent color match for facial skin, and nonhair-bearing skin is available if lining of the oral cavity is required. The deltopectoral flap provides superior coverage for the carotid artery.

Adult↗