Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.

[Q]: Abstract: It has been assumed that the molecular weight (MW) cut-off of a newly fabricated polysulfone capillary dialyzer (F60, Fresenius, FRG) is similar to that of the human glomerulus. We recently tested the device in vivo and found this not to be so, based on the device's ability to eliminate substances of a MW of 10,000 to 60,000 daltons. One of the reasons for this discrepancy was found to be the influence of secondary membrane formation on solute permeability. Endogenous marker substances of a defined MW (beta 2-microglobulin, myoglobin, RBP, alpha 1-microglobulin, acid alpha 1-glycoprotein, alpha 1-antitrypsin, prealbumin, and albumin were measured by laser nephelometry or radioimmune assay; sieving coefficients (SC) and protein eliminations were calculated for each low MW protein.
[A]: Blood

[Q]: Abstract: Lymphoscintigraphy with Technetium antimony sulfur colloid (TASC) was used in four patients with malignant melanoma to identify the pattern of lymphatic drainage, allowing selective lymph node dissection. TASC is safe and predictive of lymph node drainage patterns. Using this technique allows visualization of multiple tiers of lymph nodes in 2 to 6 hours.
[A]: Adult

[Q]: Abstract: The metabolism of vitamin D3 was studied in chicks after experimental fractures were performed on their tibiae. The chicks were fed for 3 weeks a vitamin D-deficient diet but were supplemented with radioactive labeled vitamin D3. The chicks were then divided into two groups. In the first group the right tibia was fractured, whereas the second group served as nonfractured control group. During the following days of fracture healing, the metabolites of [3H]vitamin D3 were measured in callus, epiphysis, diaphysis, plasma, duodenum, and kidney. Histological examination of calluses and bones, measurements of intestinal absorption of calcium, and renal production of dihydroxylated metabolites of vitamin D3 were performed as well. The levels of the dihydroxylated metabolites were increased in the calluses and the levels of [3H]24,25-dihydroxyvitamin D3 were found to coincide with the formation of cartilaginous tissue and with the renal production of this steroid. In the duodenum of the fractured chicks, the levels of [3H]1,25-dihydroxyvitamin D3 dropped significantly during the first week after fracture, coinciding with reduction in the intestinal absorption of calcium. In the plasma during those 3 weeks of healing process the levels of [3H]1,25-dihydroxyvitamin D3 were far below normal. These findings indicate that during the process of fracture repair, changes in the metabolism and expression of vitamin D are taking place in order to meet the new requirements of the body under stress condition of skeletal fracture.
[A]:
Animal