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Biomedical subjects

J R Cooper

Publications and source records attributed to J R Cooper.

178 records · Page 10Linked to original sources
PubMedDate not supplied

Developmental toxicity of JP-8 jet fuel in the rat.

JP-8 aviation fuel is being phased in as a replacement for both JP-4 and JP-5 jet fuels presently in use by the Air Force and Navy, respectively. At the present time, 11% of active-duty Air Force personnel are women of child-bearing age. This study was undertaken to determine the threat posed to the unborn fetus should female active-duty personnel come in contact with JP-8 while pregnant. Time-mated Sprague-Dawley rats were dosed orally with JP-8 at 0, 500, 1000, 1500 and 2000 mg kg-1 day-1 on days 6-15 of pregnancy. The number and type of fetal malformations and variations observed did not differ significantly between dose groups. Dams in the 1000, 1500 and 2000 mg kg-1 day-1 groups gained significantly less body weight during pregnancy than did control dams. Embryo toxicity was indicated by a significant reduction in fetal body weight in the 1500 and 2000 mg kg-1 day-1 dose groups.

Animals↗
PubMedDate not supplied

Teratologic evaluation of liquid propellant (XM46) in the rat.

The Army has proposed using a liquid propellant (XM46) composed of hydroxylammonium nitrate (HAN) and triethanolammonium nitrate (TEAN) in its Advanced Field Artillery System. This study was undertaken to determine the potential threat to the unborn fetus should female Army personnel become exposed to this compound during pregnancy. Timed pregnant rats (Crl:CD Charles River Laboratories, Inc.) were purchased on day 4 of pregnancy and divided into a control and four dose groups of 25-28 animals each. Animals were dosed orally with XM46 on days 6-15 of pregnancy at the rate of 0.0, 162.5, 325 and 650 mg kg-1 body wt day-1. Cesarean section was performed on gestation day 20. Maternal body weight was significantly reduced in the 650 mg kg-1 day-1 dose group on days 5-20 of pregnancy. Likewise, maternal food consumption was significantly reduced in the high-dose animals during the dosing period. There were no exposure-related differences in fetal weight, number, sex or frequency of malformations observed in fetuses between control and treated dams. The results of this study indicate that XM46 is not a teratogen in the rat.

Administration, Oral↗
PubMedDate not supplied

Developmental toxicity of OTTO Fuel II in the rat and rabbit.

OTTO Fuel II (OFII) is a propellent used by the United States Navy in its Mk 46 and Mk 48 torpedoes. Owing to the possibility of human exposure during fueling and defueling operations, studies were initiated to determine if OFII was a developmental toxin. Phase I of the investigation involved dosing four groups of time-mated Fischer-344 rats with OFII. The fuel was administered dermally at the rate of 0, 400, 2000 and 4000 mg kg-1 day-1. A significant reduction in body weight was seen at necropsy in dams receiving 2000 and 4000 mg kg-1 day-1 of OFII. Fetuses from these dams also weighed significantly less than control fetuses. Phase II of the investigation involved dosing of artificially inseminated rabbits with OFII. The fuel was administered to the skin of the animal's back at the rate of 0, 100, 316 and 1000 mg kg-1 day-1. Maternal toxicity was evidenced by a significant reduction in body weight of the dams in the 1000 mg kg-1 day-1 dose group on days 20 and 25 of gestation. There were no significant differences observed in maternal weight or fetal weight at necropsy. Morphological examination of both rat and rabbit fetuses failed to reveal significant evidence of fetal malformations.

Animals↗
PubMedDate not supplied

The effects of JP-8 jet fuel on male Sprague-Dawley rats after a 90-day exposure by oral gavage.

The U.S. Air Force is converting from JP-4 jet fuel to the less volatile JP-8 jet fuel, which is similar to commercial Jet Fuel A. Our previous 90-day inhalation study with JP-8 vapor, using F-344 rats and C57BL/6 mice, resulted in no treatment-related adverse effects other than alpha 2-microglobulin nephropathy in male rats (Mattie et al., 1991). In the present study, male rats were dosed with neat JP-8 (0, 750, 1500, 3000 mg/kg) daily by gavage for 90 days in an effort to characterize the kidney lesion and assess further any additional adverse effects associated with prolonged oral exposure to this fuel. Results of this study revealed a significant dose-dependent decrease in body weights of rats exposed to JP-8. Male rat-specific alpha 2-microglobulin nephropathy was observed by histopathologic examination. A number of significant changes were also seen in blood and urine that were not dose-dependent. Additional treatment-related effects were a gastritis and a perianal dermatitis. Although there were no histopathological or weight changes in the livers of exposed rats, there was an increase in the liver enzymes AST and ALT. The elevated enzymes did not increase with increasing dose of JP-8.

Aircraft↗
PubMedDate not supplied

Ceramic bearing surfaces in total artificial joints: resistance to third body wear damage from bone cement particles.

Studies of explanted Charnley hip prostheses have shown damage or scratching of the polished stainless steel femoral heads. This surface damage is probably due to third body wear by bone cement particles. Damaged femoral heads will produce increased wear rates of ultra high molecular weight polyethylene (UHMWPE) acetabular cups. Sliding wear tests carried out in the laboratory have shown that alumina ceramic counterfaces are more resistant to third body damage from bone cement particles than stainless steel counterfaces. The use of the ceramic femoral heads in artificial hip joints will help to preserve the smooth surface finish on the femoral bearing surface, which is necessary to ensure low wear rates of the UHMWPE cup throughout the lifetime of the prosthesis.

Biocompatible Materials↗
PubMedDate not supplied

Pitfalls in radiological diagnosis of lower limb injuries.

Correct evaluation of trauma requires the radiological examination to be tailored to the clinical assessment which determines not only the area imaged and projections obtained, but on occasion further imaging even in the absence of plain film abnormality. We illustrate these principles in the lower limb, and area where accurate diagnosis can be both difficult and important.

Age Factors↗
PubMedDate not supplied

Methadone treatment and acquired immunodeficiency syndrome.

In light of the recent growth in public financial support for the rapid expansion of drug abuse treatment capacity, the unique effectiveness of methadone hydrochloride treatment in reducing intravenous opioid abuse and the associated sharing of injection equipment is reviewed and discussed, and its potential effect on preventing the spread of acquired immunodeficiency syndrome is examined. In addition to methadone, treatment variables that clinical research suggests are integral to effective treatment are identified. Methadone treatment is one of the most helpful means of reducing the risk of acquired immunodeficiency syndrome available, provided that programs of quality are expanded. The medical profession and universities are urged to take steps to ensure quality effort in prevention and treatment.

Acquired Immunodeficiency Syndrome↗