Applications of acoustic charge transport.

The emerging technology of acoustic charge transport (ACT), which has enabled the implementation of powerful signal processors capable of handling high-speed RF and microwave signals in their natural analog domain, is reviewed. The development of ACT technology has led to the implementation of fully programmable analog signal processors capable of performing over 45 billion multiply-and-accumulate operations per second. These processors are finding application as adaptive filters and equalizers in a variety of commercial and military systems.

Cerebrovascular adaptations to high-altitude hypoxemia in fetal and adult sheep.

In the fetus and infant, high-altitude hypoxemia is associated with increased cerebrovascular morbidity. To test the hypothesis that this increased morbidity involves changes in cerebrovascular endothelial and smooth muscle function, we examined middle cerebral, posterior communicating, basilar, and common carotid arteries obtained from 23 normoxic fetuses, 19 hypoxemic fetuses maintained at high altitude (3,820 m) from 30 days gestation to near term (approximately 143 days), 55 normoxic non-pregnant adults, and 24 hypoxemic nonpregnant adults maintained at the same altitude and duration as the hypoxemic fetuses. Long-term hypoxemia was associated with several significant changes in both fetal and adult arteries, including a generalized increase in base-soluble protein (5-50%), a depression of the maximum potassium-induced tensions (16-49%), and a depression of the relaxation responses to S-nitroso-N-acetylpenicillamine (1-11%), which releases nitric oxide into solution upon hydration.

Impact of reimbursement regulations on patient management.

The Medicare End-Stage Renal Disease (ESRD) Program has saved the lives of thousands of patients with chronic renal failure; however, the absolute cost of the program has steadily increased since its inception in 1972 and quickly exceeded all budget estimates, although the actual cost per patient has increased only 69%, which is less than half the inflation rate. Cost-containment efforts have resulted in progressive reductions in reimbursement provided by Medicare to both physicians and dialysis centers. The reimbursement amount per dialysis treatment--the largest component of ESRD expenditures--has actually decreased from $138 in 1974 to approximately $54 in 1991 when measured in constant dollars.

Prevalence and correlates of hospital-based autologous blood programs: a statewide survey.

To identify potential barriers to use of autologous blood procurement to minimize homologous blood transfusion needs during elective surgery, the authors conducted a telephone survey of 120 blood bank directors, representing 138 Ohio hospitals. The prevalence of autologous blood procurement facilities, estimated volume of autologous blood, and attitudes and perceptions of the directors toward autologous blood predeposit programs were assessed. Analysis of the data indicated that 30% of Ohio hospitals have autologous blood procurement facilities; larger hospitals were more likely to have this facility.

Pregnancy-induced changes in ovine cerebral arteries.

We examined the effects of pregnancy on the ovine cerebral vasculature by comparing several characteristics of isolated endothelium-intact segments of three intracranial arteries including the middle cerebral (MCA), posterior communicating (PC), and basilar (BAS) arteries taken from pregnant sheep (138-143 days gestation, term approximately 145 days) and nonpregnant controls. For comparison, segments of the extracranial common carotid (COM) artery were also studied. With pregnancy, vessel water content increased (5.

Developmental changes in ovine cerebral artery composition and reactivity.

We have examined age-related changes in segments of common carotid (Com), basilar (Bas), posterior communicating (PC), and middle cerebral (MC) arteries taken from 14 near-term fetal lambs, 62 newborn lambs 3-7 days old, and 42 adult nonpregnant sheep. Transition from fetal to newborn life was associated with a decreased water content in all arteries ranging from 0.6% (Com) to 2.

Structural and functional analysis of the human neutrophil 1-15 antigen, an Mr 65,000 to 70,000 activation-associated membrane proteinase.

Previous studies with the anti-neutrophil/antichymotrypsin mAb 1-15 have identified an activation-associated, chymotrypsin-like activity within the membrane fraction of isolated human neutrophils (PMN). In the present study, the molecular and biochemical characteristics of mAb 1-15 Ag/proteinase were determined. On casein/acrylamide sizing gels, PMN membrane preparations were found to contain an Mr 58,000 to 84,000 band of Ca2(+)-dependent proteinase activity.