Response to therapy in acute myeloid leukaemia: An explanation of two unrelated findings

Androgen therapy prolongs complete remission in acute myeloid leukaemia (AML). (1,2) $\text{In}$$\text{vitro}$ studies of clone formation by myeloid leukaemia cells in semi-solid agar cultures have revealed a relationship between culture findings and response to chemotherapy. (3) These seemingly unrelated findings may be explained by the hypothesis proposed here which relates clone size in culture and sensitivity to regulators of granulopoiesis with level of differentiation in the granulocyte-monocyte pathway. This hypothesis not only suggests other means of therapy which may be equally or more effective while lacking the side effects of androgen therapy, but also predicts which patients are most likely to benefit from such therapy.     

Pasteurella multocida. Infections after domestic animal bites and scratches.

Pasteurella multocida is a common cause of infection followingbites or scratches caused by dogs and cats. However, it is rarely reported and appar-ently often overlooked as a pathogen. It causes the typical clinical manifestationsof a rapidly developing cellulitis at the site of injury. The infection is potentiallydangerous and can cause a chronic local infection of deep tissues and septicemia. However, it responds well to several antimicrobials, with penicillin being the drug ofchoice     

PCB levels in egg yolks associated with embryonic mortality and deformity of hatched chicks

The effect of exposing White Leghorn hens for six weeks to 50 ppm of Aroclor 1254 in water was investigated. While egg production decreased temporarily, no significant effects were noted on egg weights or fertility. Incubation of eggs from exposed hens indicated that this polychlorinated biphenyl (PCB) did not interfere with gametogenesis and fertilization. As Aroclor 1254 accumulated in the yolk, however, embryonic development was arrested at progressively earlier developmental stages. When PCB was removed from the water there was an initial rapid decline in the PCB content of the yolk and a slow return of the normal developmental pattern of the embryo. Leg, toe, and neck deformities were present in many of the chicks hatched from eggs in which yolk PCB level was 10–15 ppm or more. The gross appearance of the liver and the presence of hemorrhages suggest that the liver and the vascular elements may be targets for PCB action.     

The accuracy of binocular vergence for peripheral stimuli

Two experiments were conducted to investigate the roles of dark vergence and retinal eccentricity as factors influencing binocular vergence responses. A nonius alignment technique was used to measure vergence responses in total darkness (dark vergence) and for dim binocular stimuli presented at retinal eccentricities ranging from 2° to 8° over distances ranging from 28.5 to 342cm. The results indicate that vergence was progressively less accurate with stimuli at increasing retinal eccentricities and that errors of fixation were biased toward the individual's dark vergence position. The hypothesis that dark vergence represents the functional resting state of the vergence system which influences oculomotor fusional responses under a variety of conditions is discussed.