Expression in music and literature

Thesis (M.A.)--Boston Universit

The Cost of Mupirocin Resistance in \u3cem\u3eStaphylococcus\u3c/em\u3e.

Control of antibiotic resistance in bacteria is based on the concept that resistance incurs a fitness cost in non-selective conditions. Fitness costs were assessed for low- and high-level mupirocin resistance in locally-derived Staphylococcus aureus and S. epidermidis. Costs of resistance were assessed in pure cultures by comparing growth curve characteristics and in mixed culture as the proportion of resistant cells surviving. Costs were not present in comparisons of growth rates among groups of naturally-occurring isolates from the different resistance categories. However, in S. aureus, growth rates within resistance categories differed by approximately 30 – 90%. Among near-isogenic pairs of strains, fitness costs ≥10% were present in three of eleven pairs under pure culture and in six of eleven pairs under competition in mixed culture. Differences in intrinsic growth rates could easily mask fitness costs of the magnitudes observed. Thus, clinical outcomes also depend on whether there is a mixed infection and if so, on the growth rates of strains present

What, for the University, is Solidarity? Catholic Higher Education and the Unfinished Reception of Gaudium et Spes

Introduction: Forty years ago, Jesuit philosopher and theologian Ignacio Ellacuría accepted an honorary doctorate from Santa Clara University and delivered a commencement address with which some of us here today are likely familiar. In the concise and penetrating speech, Ellacuría proposed a vision of the university as both a center of intellectual inquiry and cultural production, and as a “social force”—a place concerned with the transformation of social reality

The Effects of Xanthine Analogs on Neonatal Rat and Adult Mouse Respiration

Apnea, a prolonged cessation of breathing, is commonly seen in premature infants. This condition, in its severest form, can be lethal and is a suspected cause of sudden infant death syndrome (SIDS). Sometimes referred to as apnea of prematurity, recurrent apnea is presently being treated with respiratory stimulants known as methylxanthines (MX) such as theophylline and caffeine. The benefits of MXs are accompanied by central nervous system stimulation and cardiostimulation which may be detrimental to a premature infant. Theophylline (1,3-diMX) has been shown to produce some of its effects by antagonizing endogenous adenosine. Another xanthine, enprofylline (3-propylxanthine), is presently being investigated as an antiasthmatic drug due to its bronchodilating effects. Unlike theophylline it has no CNS toxicity nor does it antagonize adenosine, except in high concentrations. Due to its lack of antagonism one would deduce that enprofylline would not stimulate respiration. The present study focused on the effects of these two xanthines on the respiration of adult mice and newborn rats. Respiratory studies were conducted on newborn rats (4- to 7-days old) and adult mice (20-30 g), using the volume displacement body plethysmograph. Subcutaneous injections of aminophylline (the ethylenediamine salt of theophylline) or enprofylline were administered and the effects compared to baseline respiration. Aminophylline (20 mg/kg) significantly increased VE by 30% in adult mice with a peak effect at 20 min. This increase was due to significant increases in both VT (13%) and f (18%). Aminophylline significantly increased VE by 44% in neonatal rats with a peak effect at 20 min. The increase was due to increases in both VT (30%) and f (9%). Only f was significantly greater than saline controls. Enprofylline (20 mg/kg) showed no consistent pattern of effects nor nor were its effects significantly different from saline for adult mice or neonatal rats. There were no significant differences in VE between doses (10, 20 and 40 mg/kg) of aminophylline in mice. Enprofylline (20, 40 and 80 mg/kg) also showed no significant differences in VE between doses for mice. However, doses of enprofylline were significantly different from one another in neonatal rats. The trend shown by enprofylline (40 mg/kg) was a consistent respiratory depression whereas the 80 mg/kg dose showed a latent stimulation in respiration. During these experiments 7 of 8 pups died after injection of 80 mg/kg enprofylline. In summary aminophylline stimulated respiration in both adult mice and neonatal rat pups, while enprofylline did not stimulate respiration at any dose tested, except at a dose which was lethal to neonatal rats. These data support the hypothesis that theophylline stimulates respiration by adenosine antagonism

The Effects of Xanthine Analogs on Neonatal Rat and Adult Mouse Respiration

Apnea, a prolonged cessation of breathing, is commonly seen in premature infants. This condition, in its severest form, can be lethal and is a suspected cause of sudden infant death syndrome (SIDS). Sometimes referred to as apnea of prematurity, recurrent apnea is presently being treated with respiratory stimulants known as methylxanthines (MX) such as theophylline and caffeine. The benefits of MXs are accompanied by central nervous system stimulation and cardiostimulation which may be detrimental to a premature infant. Theophylline (1,3-diMX) has been shown to produce some of its effects by antagonizing endogenous adenosine. Another xanthine, enprofylline (3-propylxanthine), is presently being investigated as an antiasthmatic drug due to its bronchodilating effects. Unlike theophylline it has no CNS toxicity nor does it antagonize adenosine, except in high concentrations. Due to its lack of antagonism one would deduce that enprofylline would not stimulate respiration. The present study focused on the effects of these two xanthines on the respiration of adult mice and newborn rats. Respiratory studies were conducted on newborn rats (4- to 7-days old) and adult mice (20-30 g), using the volume displacement body plethysmograph. Subcutaneous injections of aminophylline (the ethylenediamine salt of theophylline) or enprofylline were administered and the effects compared to baseline respiration. Aminophylline (20 mg/kg) significantly increased VE by 30% in adult mice with a peak effect at 20 min. This increase was due to significant increases in both VT (13%) and f (18%). Aminophylline significantly increased VE by 44% in neonatal rats with a peak effect at 20 min. The increase was due to increases in both VT (30%) and f (9%). Only f was significantly greater than saline controls. Enprofylline (20 mg/kg) showed no consistent pattern of effects nor nor were its effects significantly different from saline for adult mice or neonatal rats. There were no significant differences in VE between doses (10, 20 and 40 mg/kg) of aminophylline in mice. Enprofylline (20, 40 and 80 mg/kg) also showed no significant differences in VE between doses for mice. However, doses of enprofylline were significantly different from one another in neonatal rats. The trend shown by enprofylline (40 mg/kg) was a consistent respiratory depression whereas the 80 mg/kg dose showed a latent stimulation in respiration. During these experiments 7 of 8 pups died after injection of 80 mg/kg enprofylline. In summary aminophylline stimulated respiration in both adult mice and neonatal rat pups, while enprofylline did not stimulate respiration at any dose tested, except at a dose which was lethal to neonatal rats. These data support the hypothesis that theophylline stimulates respiration by adenosine antagonism

Reinforcer Demand Elasticity Under Direct Competition Between Rats

Economic theory predicts that cost is an inverse function of the quantity of a commodity. This has also been shown in studies of behavioral economics (Dougan, 1992). According to the law of supply and demand, competition between organisms should drive prices up more rapidly. Previous studies with rats have failed to find an effect of competition; however, the competition was indirect in those studies (Johns, unpublished thesis). In the present experiment, twelve female rats actively competed in pairs for reinforcers on each of four modified fixed interval (FI) schedules: FI 30 s, FI 60 s, FI 120 s, and FI 240 s. A modified operant chamber was used and the animals were separated by a wire barrier. For each schedule, the animals were tested both with and without competition from another rat. Competition involved a pair of animals responding on separate bars where only one would receive reinforcement on a given trial. The non-competition days served as controls. As predicted by the law of supply and demand, the competition resulted in increased cost. The results have a variety of implications for schedule behavior in general and behavioral economics in particular

Malnutrition and gender relations in Western Kenya

Child malnutrition, which is an increasing problem in Western Kenya, is addressed primarily through efforts to reach the individual mother with information about proper feeding of her children. A study carried out in Siaya, Kisumu and Busia Districts showed that mothers perceived nutrition problems differently, emphasizing their embeddedness in gender and family relations. In situations of marital conflict, male labour migration, and impoverishment, women must rely on support from others; thus health education should be addressed to husbands, grandmothers and mothers-in-law as well as mothers