Skin blood flow during histamine flare using the clearance of epicutaneous applied Xenon-133 in diabetic and non-diabetic subjects

The increase in skin blood flow produced by both reactive hyperemia and histamine was examined in 8 normal, 8 diabetic and 3 cancer patients using the epicutaneous Xenon-133 clearance method. The histamine flare response in both diabetic and cancer groups was reduced compared to that in the normal group. There was no significant difference in the reactive hyperemia responses. It is concluded that the reduction in the histamine flare response is due to a defect in the sensory nerves mediating the axon reflex and not due to a change in the vascular response.

Exposure to polybrominated biphenyls. Some effects on personality and cognitive functioning

Twenty-one persons exposed to polybrominated biphenyls (PBB) were compared with hospital volunteers on a battery of tests measuring memory, motor strength and coordination, cortical-sensory perception, personality, and higher cognitive functioning. Patients exposed to PBB were selected for this study only if they had persistent medical complaints. The PBB adipose levels did not correlate with performance on any test in the battery. The two groups did differ on the Minnesota Multiphasic Personality Inventory, suggesting an adjustment reaction with depressive symptoms and somatizing defenses. Persons exposed to PBB were also impaired relative to control subjects on tests of prose recall, short-term memory, concentration, and cognitive flexibility. However these differences vanished when group differences on education and personality were statistically held constant. The selective admission criteria for this study limit the generalizability of these findings.

Interaction of ribosomes and the cell envelope of Escherichia coli mediated by lysozyme

Evidence is presented suggesting the existence of a natural ribosome-membrane complex. A reconstruction system is described wherein free ribosomes form a complex which appears to involve cell fragments. The reconstructed complex is similar in stability to the inferred natural complex. The reconstructed complex is generated by lysozyme, and it is concluded that at least part of the inferred natural complex is also generated by lysozyme. These results are discussed with reference to existing data concerning certain membrane-associated systems in bacteria.

Screening of Escherichia coli temperature-sensitive mutants by pretreatment with glucose starvation

A system for screening Escherichia coli temperature-sensitive mutants is described. The system involves glucose starvation and minimizes ambiguities introduced by the interdependencies of macromolecular synthesis during balanced growth. The system permits the quick recognition of protein synthesis mutants and their classification into two general catagories. Complete protein synthesis mutants are unable to make any polypeptide material, whereas partial protein synthesis mutants are able to produce inactive proteins. The phenotypes of several mutants are described.