Acute effects of different phosphorus sources on calcium and bone metabolism in young women: a whole-foods approach.

The recommended dietary phosphorus intake is exceeded in the typical Western diet. However, few studies have been conducted on the bioavailability and metabolic consequences of dietary phosphorus from different food sources. In this study, acute effects of dietary phosphorus from three different food sources and a phosphate supplement on calcium and bone metabolism were investigated. Sixteen healthy women aged 20-30 years were randomized to five controlled 24-hour study sessions, each subject serving as her own control. At the control session, calcium intake was ca. 250 mg and phosphorus intake ca. 500 mg. During the other four sessions, phosphorus intake was about 1,500 mg, 1,000 mg of which was obtained from meat, cheese, whole grains, or a phosphate supplement, respectively. The foods served were exactly the same during the phosphorus sessions and the control session; only phosphorus sources varied. Markers of calcium and bone metabolism were followed. Analysis of variance with repeated measures was used to compare the study sessions. Only the phosphate supplement increased serum parathyroid hormone (S-PTH) concentration compared with the control session (P = 0.031). Relative to the control session, meat increased markers of both bone formation (P = 0.045) and bone resorption (P = 0.049). Cheese decreased S-PTH (P = 0.0001) and bone resorption (P = 0.008). These data suggest that the metabolic response was different for different foods.

Rat lab for fun and profit.

Many applied behavior analysts have little or no personal exposure to the basic animal experimentation that provided the foundation for applied behavior analysis. However, personal experience in the animal laboratory provides many benefits to students of applied behavior analysis. Animal laboratory experience provides convincing, vivid illustrations of basic principles of learning and facilitates generalization and application of the basic principles. The laboratory experience also teaches interpersonal skills that may be important in future employment in applied fields. The animal laboratory can also provide public relations opportunities, especially with university-sponsored events such as the Rat Olympics. These points, as well as concerns about the resources needed for an animal laboratory and compliance with federal animal-use guidelines, are addressed. It is concluded that the animal laboratory offers many educational profits to students while making learning fun for a reasonable outlay of effort and resources.

Intracortical fissuring in osteomyelitis.

Cortical fissuring, a well-recognized radiographic sign of osteomyelitis, represents spread of infection through the haversian system with osteoclastic bone resorption. In the proper clinical setting this finding may be recognized before there is other evidence of bone destruction or periosteal reaction. Three cases are presented that illustrate the sign at a relatively early stage in the progress of the osteomyelitis. While fissuring was previously considered evidence of sickle cell anemia, only one of our patients had sickle hemoglobin.