Myopathy associated with human immunodeficiency virus infection: report of a case

This paper explores nursing's current fascination with defining and exploring the term 'caring'. Fear of caring is proposed as the reason for this fascination. Factors at the root of this fear are identified and an expanded definition of caring (one which arises from the dispelling of such fear) is proposed. This expanded definition is given a new label--loving. For, as this author contends, has not loving always been at the heart of nursing?     

Noradrenergic abnormalities in the genetically epilepsy-prone rat

The genetically epilepsy-prone rat (GEPR) has central nervous system noradrenergic deficits as compared to normal rats. It is possible that these deficits contribute to seizure predisposition because they are exhibited by seizure-naive as well as by seizure-experienced GEPRs. On the basis of pharmacological studies, it is hypothesized that there is an inverse relation between seizure predisposition and levels of noradrenergic activity in brain. Neurochemical studies indicate that deficits exist in areas innervated by both the locus ceruleus and the lateral tegmental noradrenergic systems. These deficits exist in GEPRs without seizure experience and are more pronounced in the severe seizure strain as compared to the moderate seizure strain. We review eight experimental steps undertaken to identify more precisely the anatomical location of noradrenergic determinants of seizure predisposition. These steps illustrate the theoretical bases for the studies and describe the specific experiments completed. Evidence supports the hypothesis that noradrenergic deficits in the superior colliculus and/or ventrally adjacent regions are determinants of seizure predisposition.     

Factors influencing pressurization of the femoral canal during cemented total hip arthroplasty

Successful cement pressurization with total hip arthroplasty depends on the capacity of the cement gun and its ability to pressurize the canal and the integrity of the intramedullary plug and the proximal seal used to contain the cement bolus during pressurization. In the laboratory, the authors measured the volume of cement delivered by two cement guns (from Zimmer, Warsaw, IN, and Howmedica, Rutherford, NJ) in comparison with typical values for the volume of the medullary canal following standard surgical preparation. The two cement guns studied delivered 93 and 138 mL cement, respectively. In comparison, the volume of the intramedullary canal ranged from 35 to 70 mL using a standard femoral prosthesis (Precision Hip System, Howmedica). Peak pressures developed during cement injection using the cement guns were 73.6 +/- 27.1 psi for the Zimmer system and 47.3 +/- 16.9 psi for the Howmedica system. Both devices were able to sustain a minimum pressure of at least 6.5 psi through cementing when used in conjunction with a flexible pressurizing seal. The mechanical performance of five designs of intramedullary plugs was assessed by monitoring plug displacement during cement pressurization in reamed cortical specimens. The performance of each device was judged by its ability to withstand cement pressures of 50 psi without displacement within the medullary canal. On the basis of this test, the probability that these plugs would exceed this criterion when used with the femur was estimated to range from 24 to 94%. Few of the commercially available plugs were able to withstand cement pressures routinely generated using standard cement delivery systems.     

Capacity for red blood cell aggregation is higher in athletic mammalian species than in sedentary species

The purpose of this study was to show that two rheological parameters, red blood cell (RBC) sedimentation rate and apparent blood viscosity at low shear rate, characterizing the degree of RBC aggregation, correlate significantly with the maximal mass-specific rate of oxygen consumption or aerobic capacity (VO2max). Comparisons were made within two groups of similarly sized athletic and sedentary species: group 1, pronghorn antelope, dog, goat, and sheep; and group 2, horse and cow. The pronghorn antelope (Antilocapra americana) is one of the most athletic mammals, and we have obtained data on the rheological properties of blood from this species for the first time. The values of apparent viscosity at hematocrit = 40% and shear rate = 0.277 s-1 measured in a rotational viscometer were 59.5, 42.6, and 9.1 cP for antelope, dog, and sheep blood, respectively, and 55.3 and 11.5 cP for horse and cow blood, respectively. The viscosity values for antelope, dog, and sheep blood can be correlated with aerobic capacity: ln viscosity = 4.48-106.3 VO2(-1)max (r2 = 0.998; P < 0.05). The values of RBC sedimentation rate at hematocrit = 40% were 12.8, 7.0, and 0 mm/h for antelope, dog, and sheep blood, respectively, and 45.3 and 0.1 mm/h for horse and cow blood, respectively. Therefore, the data showed that the athletic species exhibit a consistently higher degree of RBC aggregation than do the corresponding nonathletic species.