Tilmicosin as a single injection treatment for respiratory disease of feedlot cattle.

Tilmicosin, a new semi-synthetic macrolide antibiotic, was evaluated in eight field trials as a single subcutaneous injection at dosages of 0 (placebo), 5, 10 and 20 mg/kg for the treatment of naturally occurring respiratory disease in feedlot cattle. Animals for these trials were selected from large groups of recently-shipped feeder cattle at the time clinical signs of respiratory disease and body temperature of 40.6 degrees C or higher were observed. Treated animals were evaluated daily for 10 days and finally at day 28. Each animal was weighed on the first day and again on day 28. Animals that died were necropsied. All treatment dosages were effective in significantly lowering mortality, improving weight gains, lowering body temperature, and reducing the severity of clinical signs when compared to the placebo-treated controls. Body temperature was the only variable with statistically significant differences among the dose levels.

Effect of monensin and tylosin on average daily gain, feed efficiency and liver abscess incidence in feedlot cattle.

Fourteen trials were conducted to evaluate the effects of feeding monensin at 33 ppm alone, tylosin at 11 ppm alone and the two feed additives in combination on the average daily gain, average daily feed intake, feed:gain ratio and the incidence of liver abscesses in feedlot cattle. Monensin reduced feed intake and improved feed efficiency (P less than .05), and had no effect on average daily gain. Tylosin improved average daily gain (P less than .05) and had no effect on daily feed intake. The effect of tylosin on feed efficiency approached significance. The interaction of monensin and tylosin was nonsignificant for daily gain, daily feed intake and feed:gain ratio. Monensin had no effect on liver abscess incidence, while tylosin reduced abscess incidence from 27 to 9%.

Factors affecting retention of estradiol-17 beta silicone rubber implants in ears of steers.

A series of trials were conducted to identify the factors causing loss of estradiol-17 beta (E2-beta) silicone rubber implants from the ears of cattle and to evaluate methods of reducing this loss. Surface application of cattle feces to the ears before implanting resulted in an increase in loss of implants compared with the loss from dry, clean ears (30.6 vs 8.6%; P less than .05). Washing ears with a povidone-iodine antiseptic solution before implanting or treating implant sites with an antibiotic after implanting reduced (P less than .05) implant loss when ears were coated with the fecal slurry. Coating silicone rubber implants with .5 to 2 mg of oxytetracycline hydrochloride (OTC) reduced (P less than .0001) implant loss from 39.8 to 13.8% when ears were coated with fecal slurry. When silicone rubber implants with a 1.5-mg coating of OTC were implanted in cattle before submerging in a dipping vat, implant loss was reduced from 6.2 to 2.7%. In studies designed to evaluate mechanical factors affecting implant loss, implants that were placed in the middle of the ear in tight skin moved .79 cm toward the insertion site during a 14-d period after administration compared with 2.82 cm when placed in the base of the ear. When placed in the middle of the ear in tight skin, only 2 of 399 (.5%) implants were lost from steers submerged in a dipping vat immediately following implantation compared with 42 of 394 (10.7%) when placed in the base of the ear (P less than .0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Phorbol myristate acetate induced colony growth in Hodgkin's disease.

Discrete pleomorphic colonies were cultured from a lymph node of a patient with Hodgkin's disease using phorbol myristate acetate in semi-solid media. A mean of 216 colonies were counted after 10 days incubation. No colonies were noted after similar incubation with pokeweed mitogen or lymphocyte conditioned medium. A gradation in morphology from small lymphoid cells to giant multinucleated cells was noted. The majority (80%) of the cultured cells bore T lymphoid surface markers. The use of phorbol myristate acetate as a stimulant for colony growth of cells from the lymph nodes of Hodgkin's disease patients would appear to be of value.

A comparison of phorbol myristate acetate with phytohemgglutinin as a stimulator of in vitro colony growth of peripheral human leucocytes.

Peripheral blood mononuclear cells from normal individuals were cultured in soft agar (0.3%) with either phytohaemagglutinin (PHA) or the tumor promoter phorbol myristate acetate (PMA). PMA was found to induce colony growth under these conditions as well as that achieved by PHA. The colonies from PHA stimulation were entirely lymphoid but with PMA the type of cell was more varied with some cells that appeared to be of the granulocytic-macrophage line. PMA thus appears to have the ability to promote growth in cells other than lymphocytes in the peripheral blood under these conditions.

The checkup center as part of an ongoing medical practice.

This is a six month study of a check-up program in a group practice of eight family physicians working in partnership with consultants in many specialties. The practice size is estimated at 20,000 people. The authors discuss the value of a modified self-administered history, and present the results of laboratory, electrocardiogram and chest X-ray screens, and the conclusions reached.The cost of this service to the taxpayer is also calculated.