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.

Ex Input:
Abstract: The intraperitoneal fibrin formation and its inhibition by intraperitoneal heparin (5000 U) was investigated in six patients on CAPD. The intraperitoneal heparin concentration decreased linearily from 1.78 U/ml to 1.13 U/ml during a 4-hour dwell time. The antithrombin III-concentration increased to 0.56 +/- 0.1 mg/dl, reaching 1.87% of normal plasma values. The antithrombin III-portion of total protein was 0.62% in plasma and 0.79% in dialysate. The fibrinopeptide A-concentration, a specific product of thrombin action on fibrinogen was 37.1 +/- 11.8 ng/ml in plasma (normal range: less than 2.5 ng/ml) and 153.4 +/- 16.8 ng/ml in dialysate during regular CAPD. After the addition of 5000 U heparin the fibrinopeptide A-concentration in dialysate decreased to 11.6 +/- 2.6 ng/ml during a 4-hour dwell time. In vitro experiments showed no remarkable inhibition of fibrin formation by heparin without antithrombin III in dialysate. We suggest that the fibrinopeptide A is produced intraperitoneally and the antithrombin III-concentration in dialysate is sufficient to inhibit the fibrin formation after acceleration by heparin.

Ex Output:
Antithrombin III

Ex Input:
Abstract: A carotid-cavernous fistula recurred 16 years after a Hamby procedure. The recurrence was manifested by subarachnoid hemorrhage originating from dilated draining pial veins. The fistula was closed with a balloon catheter introduced through a patent remnant of the cervical carotid artery. Patients who have previously undergone Hamby trapping and embolization should be reassessed for an occult fistula that could predispose them to intracranial bleeding.

Ex Output:
Adult

Ex Input:
Abstract: Cell cultures of human keratinocytes contain membrane-associated thioredoxin reductase that is extremely active in reducing radicals on the outer plasma membrane. This enzyme activity was confirmed by its purification from cultures of stratified human keratinocytes by affinity column chromatography. The enzyme was assayed both in vivo and in vitro using a spin-labeled quaternary ammonium compound as the substrate, under saturating conditions in free radical substrate. Specific activities were determined by monitoring the sequential decrease in the amplitude of the electron spin resonance signal per unit of cell protein. The following properties were found: Cultures of adult stratified cells have approximately twice the thioredoxin reductase activity of neonatal cells. The enzyme is inhibited by thioprotein inhibitors (i.e., parachloromecuribenzoate and dinitrochlorobenzene). The activity is regulated by calcium concentrations of the cell culture medium. Stratified keratinocytes are half as active in medium containing 2 mM Ca++ compared with 0.1 mM Ca++ concentration. Product inhibition of the enzyme occurs with oxidized coenzyme NADP+ (i.e., 87% inhibition of enzyme activity over 30 min). The enzyme is heat stable at temperatures of 70 degrees C for 10 min. It is inactivated at 75 degrees C. A comparative study of thioredoxin reductase activity on stratified differentiated and undifferentiated rapidly growing cells was performed. Also, enzyme activity was quantitated for cultured keratinocytes isolated from vitiliginous and normal skin of the same donor. The results of this study, and the connection between this enzyme activity and UV-generated free radicals are reconciled in terms of the mechanism of action and metabolic activity of thioredoxin reductase.

Ex Output:
Adult