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.

Abstract: We report the causes of obstructive jaundice in 56 black South African patients. Chronic pancreatitis and malignant biliary obstruction occurred with equal frequency. These two conditions may be difficult to differentiate clinically and radiologically, and only operative pancreatic biopsy may be diagnostic. Choledocholithiasis caused jaundice in only 7.1% of the patients, reflecting the relatively low prevalence of gallstones in this population.
Adult

Abstract: The ability of extracranial-intracranial bypass surgery to alter favorably the natural history of ischemic cerebrovascular disease remains in question. A recently completed prospective randomized multicenter cooperative trial failed to confirm the hypothesis that the procedure prevents further cerebral ischemia in patients with atherosclerotic internal carotid artery or middle cerebral artery disease. We analyze findings of the study in detail, including possible effects on the natural history of the disease beyond the immediate perioperative period. Potential sources of bias that may have unpredictably affected the study are discussed. These include observational bias (patient and therapist not blinded), "randomization-to-treatment" bias (high morbidity after randomization but before operation), and "prerandomization" or allocation bias (patients in the study representing a selected sample of the population with cerebrovascular disease). The extensive analysis of secondary subgroups with small numbers of patients is discussed in light of the statistical methods used. Two particular classes of patients not addressed in the study who might benefit from the procedure are defined. They are patients failing the best available medical therapy and patients with clearly documented hemodynamic compromise. Possible indications for bypass surgery are suggested for the various lesions in light of the trial and of recent reports on the natural history and pathophysiology of ischemic cerebrovascular disease. Selected cases illustrating these indications are presented.
Adult

Abstract: Neutron Activation Analysis (NAA) was used to investigate trace element patterns in serum, packed cells, and dialysate of CAPD patients. The concentrations of the elements Cs, Cu, Fe, and Mn in serum and packed cells appeared to be maintained within the normal range, while the levels of the non-essential element Br in both serum and packed cells were subnormal. The serum Cr values were extremely high (20 to 50 times higher than the normal serum level). The amount of Cr absorbed from the dialysate was calculated to be ten times higher than the daily dietary uptake. The Co concentrations were normal in packed cells but were significantly increased in serum. The Rb content in packed cells was slightly lower than normal, while the serum value was normal. Se was maintained within the normal range in packed cells, but the serum concentration was slightly lower than normal. The concentrations of Zn were low in serum and appeared to be higher than normal in packed cells. In conclusion, this analysis of the trace element status of CAPD patients reveals two major abnormalities. There is an apparent loss of Br from the blood towards the dialysate and on the other hand, a dramatic accumulation of Cr into the blood as a result of the very high Cr content in the dialysate.
Comparative Study