How practice produces suboptimal heuristics that render backup instruments ineffective.

The operation of machines typically requires attention to instruments that signal the state of the machine. One safeguard against primary instrument malfunction is to provide backup instruments, but this works only if the operators react to malfunction by switching attention to the backups. Little is known about the effect of negative outcomes or feedback on allocation of attention to backup instruments.

The value of axillary dissection in T1a breast cancer.

Background: Some authors have stated the undesirability of axillary lymph node dissections for very small breast cancers, because so few of their patients have lymph node metastases (3% for T1a lesions in one series).

Methods: Of 6,308 breast cancer cases reviewed from three large urban hospitals 3,077 single primary cases with both axillary dissection and accurate tumor measurements were statistically analyzed.

Results: For T1a lesions we found axillary metastases to be four times higher (12%) than others have reported.

Surgical treatment of cancer of the pancreas in large community hospitals.

A retrospective study compares the success rates of surgical treatment of cancer of the pancreas in large community hospitals. Although none of the surgeons averaged as many as two pancreaticoduodenal resections per year for the period of this study, their results compared well with other published series except for a few centers and surgeons who did a very high volume of such resections. Results of the study indicate that well trained surgeons in well staffed and well equipped community hospitals can provide acceptable results in pancreaticoduodenectomies for cancer of the pancreas.

A correlation with type of sulfonamide resistance gene in Escherichia coli and synergy between trimethoprim and sulfamethoxazole.

Plasmids carrying type I or II sulfonamide-resistance (Sur) genes were evaluated for their effect on synergy between trimethoprim (Tmp) and sulfamethoxyzole (Smx) in E. coli. Strain J53 containing each of three plasmids (R1, pSa, and R388) with the type I Sur gene displayed a synergistic response to Tmp/Smx; strain LE392 containing a plasmid (RSF1010) with the type II Sur gene displayed no synergy.