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Biomedical subjects

M K Roberts

Publications and source records attributed to M K Roberts.

7 recordsLinked to original sources

Synthesis of lactosaminoglycan-containing glycoproteins by vascular endothelial cells.

Human vascular endothelial cells synthesize lactosaminoglycan-type glycoproteins which are found both associated with cells and secreted into the culture medium. Pronase-derived glycopeptides prepared from [3H]glucosamine-labeled glycoproteins were found to contain about 10% of the labeled products as a large size (Mr greater than 5000) 3H-labeled glycopeptide. Digestion of these 3H-labeled glycopeptides with endo-beta-galactosidase resulted in the release of smaller size saccharides, which were characterized as having the structure sialic acid----Gal----GlcNAc----Gal. Treatment of [3H]glucosamine-labeled cells with melittin caused 3H-labeled glycoconjugates to be released from the cells. Separation of released glycoproteins from proteoglycans by DEAE-cellulose chromatography indicated that melittin had released 25% of the total 3H-labeled glycoproteins from the cell and 3% of the 3H-labeled proteoglycans. The 3H-labeled glycoproteins were digested with Pronase and the resulting 3H-labeled glycopeptides were fractionated on Sephadex G-50. The large size fraction (Mr greater than 5000) now comprised about 30% of these released 3H-labeled glycopeptides. These high molecular weight 3H-labeled glycopeptides were degraded with endo-beta-galactosidase but not with testicular hyaluronidase. Analysis of the released 3H-labeled glycoproteins indicated a preferential release of glycoproteins of 70-90 kDa enriched in lactosaminoglycan-type oligosaccharides.

Amino Sugars↗

Sulfated glycoproteins secreted by human vascular endothelial cells.

Endothelial cells incorporate 35SO4 into a class of glycoproteins which are released from the cell layer into the culture medium. The incorporated 35SO4 was localized on intact oligosaccharide chains which were released from the protein either chemically by hydrazinolysis or enzymatically by a peptide: N-glycosidase activity; thus these 35S-oligosaccharides are presumably N-glycosidically linked to protein. These 35S-oligosaccharides were also isolated and analyzed as labeled glycopeptides and found to contain the terminal trisaccharide sequence sialic acid leads to galactose leads to N-acetylglucosamine. After removal of these carbohydrate residues, the remainder of this 35S-glycopeptide was susceptible to alpha-mannosidase digestion yielding a smaller 35 S-glycopeptide containing GlcNAc35SO4. Monensin (10(-8) M), a monovalent cation ionophore, inhibited the sulfation (greater than 80%) and synthesis (greater than 60%) of endothelial cell-sulfated proteoglycans which were released into the culture medium. However, neither the synthesis nor sulfation of cell-released 35S-glycoproteins was affected at similar monensin concentrations. Higher concentrations of monensin (greater 5 X 10(-8) M) inhibited the incorporation of both [3H]glucosamine and 35SO4 into cell-released glycoproteins.U

Cells, Cultured↗

Whipple's disease involving the pericardium: Pathological confirmation during life.

Cardiac involvement in Whipple's disease has been a frequent autopsy finding but is rarely recognized clinically. We report here a patient, a 63-year-old man, in whom Whipple's disease was diagnosed in 1974, based on a seven-year history of arthralgia, one-year history of weight loss and steatorrhea, and diagnostic small bowel biopsy. Despite complete regression of all joint and bowel symptoms following a prolonged course of tetracycline therapy, the patient developed incapacitating congestive heart failure and signs of constrictive pericarditis, for which a thoracotomy and pericardectomy was performed. Histologic examination revealed fibrous pericarditis with mononuclear infiltrates, including PAS-positive histiocytes. The characteristic bacilliform bodies were identified by electron microscopy in the resected pericardium. This to our knowledge is the first such demonstration during life of Whipple's disease involving the heart.

Humans↗

Assortative mating by unwed biological parents of adopted children.

Analyses of data obtained from 662 unwed couples whose children were relinquished for adoption reveal that biological parents of adopted children mate assortatively. For physical characters, assortative mating of unwed parents was similar to that of wed parents; for behavior characters, however, there was less assortative mating by the unwed parents. Because assortative mating inflates estimates of genetic parameters in adoption studies, future studies should collect information on both biological parents.

Adoption↗

Fluid resuscitation in the adult trauma patient.

Successful fluid resuscitation of the trauma patient requires prompt assessment and initiation of fluid therapy. This article discusses the fluids and blood components that may be used in the resuscitation period for the adult trauma patient, as well as potential complications of fluid resuscitation therapy and nursing interventions.

Education, Nursing, Continuing↗