Biomedical subjects
Publications and source records attributed to R Vowles.
Parenchymatous parotid tuberculosis diffusely affecting the entire gland is very rare. We present a case, associated with a primary pulmonary focus, that was confirmed after positive identification of alcohol and acid-fast bacilli in gastric washings. Both sites of infection resolved with quadruple anti-tuberculous chemotherapy.
Growth factors enhance tensile strength, angiogenesis and collagen synthesis in skin wounds. The effects were studied of a continuous intraperitoneal infusion of epidermal growth factor (EGF) on the mechanical properties of healing in linear full-thickness wounds of the stomach, ileum and colon of young pigs (n = 16, mean(s.d.) body-weight 20.1(1.9)kg). In half the animals an osmotic minipump was implanted into the peritoneal cavity to deliver recombinant human EGF at a rate of 0.5 micrograms kg-1 24 h-1. Animals were killed at 5 days and the integrity of a 20-mm ring of intestine was tested for tensile strength. Breaking strength (g mm-2) of the intestinal wounds in untreated pigs (n = 8) was: stomach 28.0(2.0), ileum 46.8(4.8), colon 85.6(4.2). Intestinal wounds in pigs (n = 8) receiving supplemental EGF had significantly increased breaking strength: stomach 32.4(2.2) (P less than 0.05), ileum 56.8(5.4) (P less than 0.05), colon 96.0(3.8) (P less than 0.01) compared with untreated animals. At 5 days after the initial injury intraperitoneal EGF increases the tensile strength of intestinal wounds in pigs.
Short-red chevron-notch samples of seven composite materials were thermal-cycled between 0 degrees C and 60 degrees C. The stress intensification factor, KIC, was found for four sample groups subjected to 10(1)-10(4) cycles, respectively. One group of uncycled samples was tested at the commencement of the investigation and another group after exposure to water for the equivalent time taken by 10(4) cycles (42 days). The KIC decreased for all materials, but the decrease after 10(4) cycles was not significantly different from that after storage in water for an equivalent period of time. These results indicate that, in the determination of KIC, the filler/matrix bond is of secondary importance to the presence of fillers. The effects of cyclic temperature changes likely to be encountered in the mouth are not a significant factor in reduction of the fracture strength of composite filling materials.