Biomedical subjects

Donald R Bell

Publications and source records attributed to Donald R Bell.

3 recordsLinked to original sources

PubMed2002

Measurement of high-molecular-weight hyaluronan in solid tissue using agarose gel electrophoresis.

The size of hyaluronan in solid tissue was measured using a combination of agarose gel electrophoresis and a radiometric assay. Radiolabeled hyaluronan binding proteins, used in the radiometric assay, were also used to detect hyaluronan after transfer to a nylon membrane following gel electrophoresis. Lane intensity on the autoradiograph was linearly related to the amount applied to the gel between 10 and 100ng. The intensity was independent of the hyaluronan molecular weight for standards with molecular weights equal to or greater than 790,000. The radiometric assay was used to measure hyaluronan irrespective of size, while gel electrophoresis was used to measure hyaluronan with molecular weights greater than 0.79x10(6) or 4x10(6). Deferoxamine was used to inhibit depolymerization during the digestion of tissue samples with protease. The molecular weight pattern was similar for skin, skeletal muscle, heart, lung, small intestine, and large intestine despite large differences in hyaluronan content. For all tissues, 58% of the hyaluronan had a molecular weight greater than 4million. All tissues showed an absence of hyaluronan with a molecular weight below 790,000. The procedure can be used to study changes in hyaluronan size in tissue during inflammation and other pathological states.

Animals↗

PubMed2002

Relationship between lymph and tissue hyaluronan in skin and skeletal muscle.

The size of hyaluronan was compared between tissue and lymph using a combination of agarose gel electrophoresis and radiometric assay. Prenodal lymph was collected from heel skin and the gastrocnemius muscle in anesthetized rabbits. The major fraction of hyaluronan in both tissues had a molecular weight >4 million. Lymph contained primarily low-molecular-weight hyaluronan (<0.79 x 10(6)), which was absent from tissue. Volume loading produced a preferential increase in the flux of low-molecular-weight hyaluronan, indicating that tissue contains a small quantity of mobile, low-molecular-weight hyaluronan. The maximum daily removal of hyaluronan by lymph was <1% of the tissue content. The amount of lysosomal hyaluronidase activity in tissue was more than enough to account for a rapid turnover of hyaluronan. The data support the conclusion that lymph drainage is not significant in the normal catabolism of hyaluronan and may represent a small amount that becomes detached from the pericellular and extracellular matrixes.

Animals↗

PubMed2002

Ischemia-reperfusion does not cause significant hyaluronan depolymerization in skeletal muscle.

The size of hyaluronan in lymph and gastrocnemius muscle was measured to test the hypothesis that reperfusion of ischemic skeletal muscle leads to hyaluronan depolymerization. Prenodal lymph was collected from the gastrocnemius muscle in anesthetized rabbits. Hyaluronan size was measured using a combination of agarose gel electrophoresis and a radiometric assay. In control legs, muscle contained primarily high-molecular-weight hyaluronan (greater then 4 x 10(6)), while lymph contained primarily low-molecular-weight hyaluronan (less than 0.79 x 10(6)) which was absent from tissue. Following 3 h of ischemia and 8 h of reperfusion, the lymph flux for high-molecular-weight hyaluronan was 25 times the value from the control leg. Neither the size nor the content of hyaluronan in tissue decreased. Muscle albumin content from the reperfused leg was 2.3 times the value from the control leg, while lymph albumin flux was 4 times the control value. Measurements following 24 h of reperfusion confirmed the absence of changes in the size or content of hyaluronan in tissue although an increased albumin content and wet weight-to-dry weight ratio indicated sustained edema. The daily removal of hyaluronan by lymph was calculated to be 2-3% of the tissue content. Since the lymph drainage of hyaluronan represented only a very small fraction of tissue hyaluronan, the amount of depolymerization was too small to produce significant changes in the tissue.

Adjuvants, Immunologic↗