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Biomedical subjects

P Donaldson

Publications and source records attributed to P Donaldson.

48 records · Page 3Linked to original sources
PubMed1992

Reconstitution of channels from preparations enriched in lens gap junction protein MP70.

Detergent-solubilized ovine lens membrane proteins, enriched in the 70-kDa gap junction component (MP70), were reconstituted into planar lipid bilayers and analyzed for channel activities. Three distinct activities were found. Those showing conductance steps of 290 pS (symmetrical 150-mM KCl solutions) had properties similar to those reported earlier for MIP26 (Ehring, G.R., Zampighi, G., Horwitz, J., Bok, D., Hall, J.E. 1990. J. Gen. Physiol. 96:631-664.) of which minor amounts were normally present in the detergent-solubilized preparations. Two novel channel activities had unitary conductances of 90 and 45 pS, were halothane sensitive and did not discriminate between sodium and potassium ions. The 90-pS channel was asymmetrically voltage dependent, and its properties would be consistent with the expected properties of junctional hemichannels.

Animals↗
PubMed1991

Autoimmune chronic active hepatitis in a family.

A positive family history of autoimmune disease is common among patients with autoimmune chronic active hepatitis, but usually autoimmunity is directed at organs other than the liver. We document for the first time the multiple occurrence of autoimmune chronic active hepatitis in a family. Out of a sibship of seven, three sisters developed this, one sister developed coeliac and autoimmune thyroid disease, one sister showed serological signs of autoimmunity, while the two brothers were well with no signs of autoimmunity. HLA typing showed that in association with the female sex DR3 seems to be more important than B8 in conferring susceptibility to autoimmune chronic active hepatitis, at least in this family.

Adolescent↗
PubMed1976

Iron and aluminum lakes of Gallo blue E as nuclear and metachromatic mucin stains.

Gallo blue E, C. I. No. 51040, Mordant Violet 54, furnishes a blue black nuclear stain when applied to tissue sections in the form of its moderately stable iron lakes. This coloring combined well with such counterstains as orange G and eosin B. The Van Gieson stain tends to decolorize mucins, cartilage, and mast cells previously stained with this dye. Its aluminum lake solutions tend to gel in a few minutes to 24 hours depending on the solvent used and the amount of Al3+ present. Aluminum lake solutions give a moderately good blue to dark blue nuclear stain and a brilliant purplish red to dark purple stain to a variety of epithelial and connective tissue mucins. Acid dye counterstains are poorly tolerated. With either lake, nuclear staining is abolished by deoxyribonuclease digestion or relatively short mineral acid extraction of DNA.

Aluminum↗
PubMedDate not supplied

Two distinct levels of gap junction assembly in vitro.

The in vitro assembly of crystalline gap junctions from detergent-solubilized sheep lens fiber cell pore complexes in the presence of endogenous lipid is a two-step process. "Mini"-gap junctions containing about 10 pore complexes assembled within 12 hr of dialysis. The removal of detergent appeared to be the sole factor required to reach this level of assembly. Further growth to micrometer-sized crystalline gap junctions required cleaved connexin, MgCl2, elevated dialysis temperature, and dialysis for 3-5 days. Molecular interactions between adjacent pore structures laterally in the membrane are vital for the second phase of assembly but appear to be of minor importance for the formation of mini-gap junctions. Parallels exist between structural aspects of gap junction assembly in vitro and the 2-D crystallization of membrane proteins in general.

Animals↗
PubMedDate not supplied

Teaching infant CPR to mothers of cocaine-positive infants.

Cocaine abuse, a major problem in our society, has increased in women of childbearing age. Because cocaine-positive infants are at greater risk for apnea/sudden infant death syndrome (SIDS), their mothers need to be instructed in infant CPR. This study compared the use of a computerized interactive video learning system to the traditional infant CPR teaching method (lecture, video, and return demonstration) to determine the most effective method. This study indicated that mothers of cocaine-exposed infants can learn infant CPR in the immediate postpartum period and that the traditional method was found to be more effective. One unexpected positive outcome was the increase in these mothers' self-esteem.

Adult↗