Preferred speed and cost of transport: the effect of incline.

Preferred speed is the behavioral tendency of animals to utilize a relatively narrow set of speeds near the middle of a much broader range that they are capable of using within a particular gait. Possible explanations for this behavior include minimizing musculoskeletal stresses and maximizing energetic economy. If preferred speed is determined by energetic economy (cost of transport, C(T)), then shifts in preferred speed should produce shifts in C(T). To test this hypothesis, preferred speeds were measured in trotting horses on the level and on an incline. The preferred trotting speed decreased from 3.29+/-0.24 m s(-)(1) on the level to 3.05+/-0.30 m s(-)(1) (means +/- s.d., N=6) on an 11.8 % incline. The rate of oxygen consumption was measured as a function of trotting speed on a treadmill and was a curvilinear function of speed in all horses under both conditions (level and 10 % incline). This curvilinear relationship resulted in a C(T) that was a U-shaped function of speed. The speed at which C(T) was minimal (i.e. at which trotting was most energetically economical) was very near the preferred speed on the level and decreased on the incline, again to a speed near the preferred speed on the incline.

Streptococcal necrotizing fasciitis complicating a conjunctival dacryocystorhinostomy.

Necrotizing fasciitis is a rare infection of the deep and subcutaneous tissue layers most commonly caused by group A beta-hemolytic Streptococcus. The disease begins as a typical cellulitis. Necrosis of the deeper tissues progresses rapidly, accompanied by a dusky, gray-blue skin discoloration with erythematous margins. Even with appropriate treatment, mortality rates remain as high as 36%. Most cases of necrotizing fasciitis have been reported in the general surgical literature, associated with trauma or as a postoperative wound infection after abdominal and gynecologic procedures. Of the 50 cases involving the eyelids reported in the literature, only three were reported to have occurred as a "postoperative" complication. This report is of the first known case of streptococcal necrotizing fasciitis complicating a conjunctival dacryocystorhinostomy.

The role of cultures in the management of ulcerative keratitis.

PURPOSE: To ascertain the importance of routine cultures and gram stains in the management of ulcerative keratitis. METHODS: We retrospectively reviewed 119 consecutive corneal ulcers seen at Sinai Hospital of Baltimore. Cultures were obtained of the corneal ulcer and of the lids and conjunctivae of both eyes. Gram stains were performed by the hospital microbiology department on corneal scrapings from each ulcer. RESULTS: Positive corneal cultures were obtained from 56 eyes (47.1%). Initial antibiotic therapy was changed based on culture results in 14.3% of culture-positive eyes that demonstrated a worsening clinical course. Gram stains were negative in all cases. The sensitivity and specificity of the lid and conjunctival cultures were determined. CONCLUSIONS: Corneal cultures are important in the management of ulcerative keratitis. Lid and conjunctival cultures have low sensitivity and specificity.

Fragmentation hemolysis: an unusual indication for valve replacement in native valve infective endocarditis.

Intravascular mechanical fragmentation of erythrocytes is an uncommon occurrence in native valve infective endocarditis. We report a case of fragmentation hemolysis in a patient with tricuspid valve endocarditis due to Staphylococcus aureus. She received transfusion of multiple units of packed red blood cells and ultimately required surgical removal of the affected valve to control the hemolytic process. We believe this to be only the fifth such reported case and the first in which surgical therapy was necessary to control the hemolytic process.