Sensitive assay for plasminogen activator of transformed cells

A sensitive in situ assay for the plasminogen activator of transformed cells is described; it uses the fluorogenic molecule 3',6'-bis(4-guanidinobenzoyloxy)-5-(N'-4-carboxylphenyl)thioureidospiro[isobenz ofuran-1(3H),9'-[9H]xanthen]-3-one. This fluorescein derivative is an excellent active-site titrant of the esterase activity of plasmin. When transformed cells are incubated with purified plasminogen and the resulting plasmin is titrated with the fluorogenic substrate, the amount of plasmin formed is linearly proportional to time and cell number. The assay is sensitive enough to detect quantitatively the plasminogen activator activity of as few as 250 transformed cells. This substrate should be useful in studying quantitatively the correlation between increased levels of plasminogen activator activity and cellular transformation and as a general active site titrant of serine proteases.

Comparison of the membrane composition of Spiroplasma citri and the corn stunt Spiroplasma

Components of membranes isolated from Spiroplasma citri and corn stunt spiroplasma grown at 28 degrees C were analyzed. On a protein basis, lipid phosphorus was lower and cholesterol was higher in S. citri. Only minor differences between the two species were found in fatty acid composition, reduced nicotinamide adenine dinucleotide diaphorase, and adenosine triphosphatase.

Possible pathogenetic mechanisms producing bovine milk protein inducible malabsorption: a hypothesis

The feeding of bovine milk to five highly allergic pediatric patients with bilateral family histories of atopy led to transient malabsorption of glucose and fat as well as systemic autonomic functional changes which may be attributable to pharmacologic actions of histamine and/or acetylcholine. It is hypothesized that during allergic reactions endogenously released smooth muscle stimulating neuromediators could provide rapid propulsion of nutrients through the absorbing portion of the gut, leading to suboptimal absorption, and that bovine milk inducible malabsorption in the atopic patients has an immuno-pharmacologic basis in its pathogenesis.

Proximal small bowel transit pattern in patients with malabsorption induced by bovine milk protein ingestion

Seven allergic patients with bovine milk or milk protein-inducible transient intestinal malabsorption exhibited radiologic signs of rapid transit of ingested barium through the proximal small intestine hours following oral challenge with bovine milk or milk protein solution. Control studies in the same patients without prior milk challenge revealed significantly more leisurely progress of contrast medium in the proximal small bowel. The possible pathogenetic role of such hasty transit through the functionally most effective portion of the digestive tract in patients with malabsorption points up the physiologic importance of roentgen examination of motility patterns in this particular segment of small bowel.