Search PubMed⌕ Search

Biomedical subjects

S C Marks

Publications and source records attributed to S C Marks.

At least 235 records · Page 13Linked to original sources
PubMed1975

Organ culture of osteopetrotic (ia) rat bone: evidence that the defect is cellular.

Calvarial bone from osteopetrotic (ia) rats and normal littermates has been cultured in a chemically defined medium supplemented with homologous serum to test for the presence of inhibitors or the absence of promoters of bone resorption in mutant serum. In addition, the response of mutant and normal bone to parathyroid extract and hydrocortisone was tested in vitro. The results indicate that mutant and normal serum do not differ with respect to their ability to support bone resorption and that ia bone responds to hydrocortisone but not parathyroid extract in organ culture. These data indicate that the skeletal defect in ia rats is not humoral but cellular.

Animals↗
PubMedDate not supplied

Blindness following bilateral radical neck dissection.

Blindness after bilateral radical neck dissection is a rare complication. A recent patient, who suffered total blindness after simultaneous bilateral radical neck dissection, is the fifth case reported. It is, however, the first with pathological study of the optic tracts. Detailed microscopic examination revealed bilateral intraorbital hemorrhagic optic nerve infarction without evidence of embolization or ophthalmic artery occlusion. The probable etiology of this event is an episode of prolonged hypotension. An additional etiologic factor may be increased resistance to blood flow caused by venous hypertension, resulting from bilateral internal jugular vein ligation.

Aged↗
PubMedDate not supplied

Eating utensil foreign bodies of the esophagus.

Large foreign bodies of the esophagus are uncommon. We report two unusual cases of eating utensil, esophageal, foreign bodies that occurred unintentionally following self-instrumentation of the oropharynx. The histories, radiographs, and clinical management of these cases are presented and discussed.

Adult↗
PubMedDate not supplied

The skeletal effects of colony-stimulating factor-1 in toothless (osteopetrotic) rats: persistent metaphyseal sclerosis and the failure to restore subepiphyseal osteoclasts.

Toothless (tl), one of four osteopetrotic mutations in the rat, is characterized by few osteoclasts, undetectable bone resorption, and failure of correction by bone marrow transplantation. We recently reported that CSF-1 treatment improves these skeletal problems but that metaphyseal sclerosis persists. In the present study we demonstrate that optimal reduction of the skeletal sclerosis in tl rats following CSF-1 treatment has lower and upper dosage thresholds and that skeletal sclerosis returns after CSF-1 withdrawal. Osteoclasts increase significantly in tl rats after CSF-1 treatment, but compared to untreated normal littermates, histochemical staining for characteristic enzymes and osteoclast number is reduced and no osteoclasts appear in the subepiphyseal areas of long bones. These data are interpreted to mean that there are dosage limits to the beneficial skeletal effects of CSF-1, that persistent sclerosis is related to the failure to restore subepiphyseal osteoclasts, that osteoclast or progenitor populations may be deficient or differ in their responses to CSF-1, and that the defect in tl rats is not merely lack of a circulating, biologically active form of CSF-1.

Animals↗
PubMedDate not supplied

Alveolar bone augmentation following the local administration of prostaglandin E1 by controlled-release pellets.

E-Series prostaglandins (PGE) are powerful osteogenic substances when given in vivo. The purpose of this work was to determine the ability of locally administered PGE1 to promote alveolar bone formation. Controlled-release pellets containing PGE1 were implanted on the lateral mandibular surface of Beagle dogs and tissues collected 4 weeks later. There was a dose-related increase in alveolar bone thickness and bone formation rates following PGE1 administration. In many cases, there was substantial new bone formation on the alveolar crest. Some increase in alveolar bone remodeling occurred with higher doses of PGE1. These results demonstrate that locally administered PGE1 may be useful for the augmentation of alveolar bone.

Alprostadil↗
PubMedDate not supplied

Local stimulation of new bone formation by prostaglandin E1: quantitative histomorphometry and comparison of delivery by minipumps and controlled-release pellets.

E-series prostaglandins (PGE) given systematically or locally in vivo can have powerful anabolic effects on bone. The comparative dose-response relationships from PGE1 given by osmotic minipump or controlled-release pellet on periosteal and intracortical bone envelopes were determined. Graded doses of PGE1 were delivered by osmotic minipump (0.0 to 16.7 mg PGE1/week) or controlled-release pellet (0.0 to 16.7 mg PGE1/week) to the lateral mandibular surface of adult dogs (2-5 years old). PGE1 was given for three weeks and tissues were collected for histology and histomorphometry one week later. At sites of maximal response, there were dose-related increases in the periosteal surface with new bone formation, average new bone thickness, maximum thickness, and new bone area. Subperiosteal bone formation was greater for comparable doses when PGE1 was delivered by minipumps. The proliferation of new bone at those sites treated with the pellets was greatest with the 8.3 mg PGE1/week/three week treatment. Periosteal bone formation did not appear to be preceded by a resorption phase, indicating that PGE1 treatment stimulated bone modeling in the formation mode. The new bone consisted of woven bone, particularly at sites with high accretion rates, and primary lamellar bone. There were some dose-related changes in intracortical remodeling indices including increases in cortical porosity, single and double-labeled surface, numbers of formation, reversal and resorption osteons, radial closure rate, and surface- and volume-referent bone formation rates. Increases in the bone formation rates indicate that PGE1 increased the recruitment of osteoblasts. Increases in the mineral appositional rate, observed at a higher dose, indicates that PGE1 stimulated bone production at the cellular level.(ABSTRACT TRUNCATED AT 250 WORDS)

Alprostadil↗