Biomedical subjects
Publications and source records attributed to G Shybut.
We describe a patient with systemic lupus erythematosus who developed osteonecrosis. The case is unusual because the osteonecrosis occurred in an unusual location, in the distal tibia. The patient had earlier developed recurrent pyarthrosis, and biopsy and culture were required to exclude osteomyelitis.
We report the use of distraction osteogenesis for segmental mandibular regeneration. This technique has been used in thousands of patients in the Soviet Union to regenerate as much as 30 cm of tubular bone in the extremities. However, we are unaware of previous experimental or clinical reports of segmental mandibular regeneration by distraction osteogenesis. In a canine model, 2.5-cm segmental mandibular defects were filled with regenerate bone in 25 days at a rate of 1.0 mm/d using bifocal distraction osteogenesis. The diameters of the regenerate segments were comparable with preexisting mandible, and all animals resumed normal oromandibular function following regeneration. The regenerate bone was evaluated radiographically, angiographically, and histologically. In the control group without distraction osteogenesis, the segmental defects failed to fill with regenerate bone. The theoretical basis for distraction osteogenesis, a detailed description of the technique, and a review of previous studies on experimental mandibular lengthening are presented.
d-N-Alkylated amphetamines were synthesized in a series up to and including d-N-butylamphetamine and potencies of these compounds were compared in (1) rhesus monkeys allowed to respond for intravenous infusions of the drugs, (2) rats allowed to drink a milk solution for 15 minutes each day and (3) isolated, spontaneously beating guinea-pig atria. In the self-administration procedure, d-amphetamine (A), d-N-methylamphetamine (NMA), and d-N-ethylamphetamine (NEA) were self-administered above saline levels at two or more doses by all animals. For these three drugs, maximal response rates were found at similar doses in all animals. However, maximal rates were generally higher in animals maintained on pentobarbital than in animals maintained on cocaine under control conditions. d-N-propylamphetamine (NPA) was self-administered above saline levels by three of four animals at one or more doses. Maximal response rates for NPA were about 1/2 of that of A, NMA and NEA, and the dose-response curve was shifted to the right of these compounds by about 4 times. d-N-butylamphetamine (NBA) maintained responding above saline levels at two doses in only one of three animals. In rats, all of the compounds decreased milk intake in a dose-related manner. A, NMA and NEA were equipotent in disrupting intake, while NPA and NBA were, respectively, 1/4 and 1/6 as potent as the shorter-chain compounds. With the exception of NBA, all compounds increased the rate of beating of the guinea-pig atrium over the range of concentrations tested. In general, for substituents larger than ethyl, potency of d-N-alkylated amphetamines was inversely related to N-alkyl length.