Publications by authors named "Highfill J"

Objective: The objective of the study was to determine if postpartum contraceptive choices by primiparous women differ by ethnicity.

Study Design: Retrospective nested cohort study analyzing women's characteristics and contraceptive choice.

Results: Of 652 participants, 312 (47.

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Although venous thromboembolism is an important cause of morbidity and mortality within the hospital, a significant proportion of at-risk inpatients do not receive measures known to reduce the risk of deep vein thrombosis and pulmonary embolism. The objective of the present study was to determine whether a pharmacy-driven alert system would, compared to usual care, be associated with a higher rate of adequate venous thromboembolism prevention measures among at-risk inpatients on a general internal medicine service. The study was a prospective, controlled trial set at a university-based teaching hospital.

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The relationship of exposure and tissue concentration of parent chemical and metabolites over prolonged exposure is a critical issue for chronic toxicities mediated by metabolite(s) rather than parent chemical alone. This is an issue for AsV because its trivalent metabolites have unique toxicities and relatively greater potency compared to their pentavalent counterparts for many endpoints. In this study, dose-dependency in tissue distribution and urinary excretion for inorganic arsenic and its methylated metabolites was assessed in female C57Bl/6 mice exposed to 0, 0.

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Toluene is found in petroleum-based fuels and used as a solvent in consumer products and industrial applications. The critical effects following inhalation exposure involve the brain and nervous system in both humans and experimental animals, whether exposure duration is acute or chronic. The goals of this physiologically based pharmacokinetic (PBPK) model development effort were twofold: (1) to evaluate and explain the influence of feeding status and activity level on toluene pharmacokinetics utilizing our own data from toluene-exposed Long Evans (LE) rats, and (2) to evaluate the ability of the model to simulate data from the published literature and explain differing toluene kinetics.

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Several studies have reported health effects of concentrated ambient particles (CAP) in rodents and humans; however, toxicity end points in rodents have provided inconsistent results. In 2000 we conducted six 1-day exposure studies where spontaneously hypertensive (SH) rats were exposed to filtered air or CAPs (< or = 2.5 microm, 1,138-1,765 microg/m3) for 4 hr (analyzed 1-3 hr afterward).

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Pollutants originating from the destruction of the World Trade Center (WTC) in New York City on 11 September 2001 have been reported to cause adverse respiratory responses in rescue workers and nearby residents. We examined whether WTC-derived fine particulate matter [particulate matter with a mass median aerodynamic diameter < 2.5 microm (PM2.

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Previous studies from this laboratory showed that the decreases in Tco and associated functional parameters often observed in rodents following exposure to xenobiotic agents are capable of modulating the subsequent toxic response and that the magnitude of this induced hypothermic response may itself be modified by a number of experimental conditions. A moderate hypothermic response, characterized by a temperature drop of approximately 2 degrees C, appears to afford the optimal protection. Studies in which exposures occur through inhalation of harmful gases or particles present a special set of problems.

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Pulmonary toxicity of ozone (O3) was examined in adult male Fischer 344 rats exposed to 0.5 parts/million O3 for either 6 or 23 h/day over 5 days while maintained at an ambient temperature (Ta) of either 10, 22, or 34 degrees C. Toxicity was evaluated by using changes in lung volumes and the concentrations of constituents of bronchoalveolar lavage fluid that signal lung injury and/or inflammation.

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Large-scale cultivation of murine bone marrow cells was accomplished in an airlift packed bed bioreactor system designed to mimic the in vivo bone marrow environment. The attachment-dependent stromal cell population, which provides the necessary microenvironment, including growth factors for subsequent hematopoietic activity, was first established within the bioreactor. This attachment-dependent cell growth occurred on the fiber-glass matrix packed in the annular region of the bioreactor.

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Previous studies from this laboratory have demonstrated a concentration-related hypothermia and increases in bronchoalveolar lavage (BAL) fluid indexes of toxicity in the rat after exposure to environmentally relevant levels of ozone (O3). In similar studies with C57BL/6J (B6) and C3H/HeJ (C3) mice, other investigators have reported differential effects on BAL toxicity indexes between the two strains after O3 exposure. The present study investigated the relationship between the reported strain differences in BAL parameters in B6 and C3 mice exposed to O3 and the induced hypothermic response.

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Previous studies involving exposures to xenobiotic agents have demonstrated decreases in physiological parameters such as heart rate (HR) and core body temperature (Tco) and have shown that these toxic responses are modulated by changes in ambient temperature (Ta). We recently published the results of a study in which male Fischer 344 rats were implanted with radiotelemetry transmitters that permitted continuous monitoring of HR, Tco, and motor activity. These animals were divided into nine treatment groups (n = 4-5/group) composed of combinations of one of three O3-exposure regimens [0.

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These studies examined the effects of exposure to near environmental levels of ozone (O3) on the unanesthetized unrestrained rat as well as the influence of changes in ambient temperature (Ta) on the observed responses. Male Fischer 344 rats were implanted with radiotelemetry transmitters that permitted continuous monitoring of electrocardiogram, heart rate, core body temperature (Tco), and activity. Telemetry animals (n = 4-5/group) were combined with nontelemetry animals to produce nine treatment groups (n = 44-50/group) composed of combinations of one of three O3 exposure regimens (0.

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Exposure of humans or animals to ozone (O3) alters spirometric and permeability functions of the lung. While these responses show clear concentration (C) dependency, the interactive role of exposure duration (T) has not been well defined. Ozone-induced alterations in forced expiratory volume in 1 s (FEV1) obtained from human studies and in levels of bronchoalveolar lavage fluid protein (BALP) obtained from studies of rats and guinea pigs were used to compare the utility of several proposed response models as functions of C and T.

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The freshwater dinoflagellate Glenodiniopsis steinii Wolsoszyńska was examined using computer-assisted three-dimensional reconstruction of serially sectioned cells observed with the transmission electron microscope and images from the scanning electron microscope. Vegetative cells contain ultrastructure typical of freshwater dinoflagellates including trichocysts, mitochondria, Golgi bodies, starch grains, and lipid bodies. The chloroplast is a single, multilobed structure, not multiple discoid chloroplasts as previously described.

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This study examined the relationship between inhibition of cholinesterase activity (CA) and thermoregulatory response in the rat following exposure to the organophosphate (OP), diisopropyl fluorophosphate (DFP). Male Long-Evans rats were injected with DFP dissolved in peanut oil in doses ranging from 0 to 1.5 mg/kg (s.

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Experiments were designed to assess the mechanisms of diisopropyl fluorophosphate (DFP)-induced changes in thermoregulation of the rat. In one study, male rats of the Long-Evans strain were injected with DFP (s.c.

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To investigate the practicality of hypothermia and hypometabolism as sensitive indices of toxicity in the mouse, oxygen consumption was monitored continuously and body temperature was measured at 30 min postinjection following the intraperitoneal administration of various metal salts. Eleven metal ions were tested: Al3+, Cd2+, Co2+, Cr2+, Cu2+, Hg2+, Mg2+, Mn2+, Ni2+, Pb2+, and Zn2+. All metals induced dose-dependent reductions in both oxygen consumption (hypometabolism) and deep body (colonic) temperature.

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Previous studies from this laboratory have demonstrated significant deficits in cardiovascular function in rats exposed to the pesticide chlordimeform (CDM) when body core temperature (TCO) was maintained at 37 degrees C. To investigate the role of TCO on CDM toxicity, similar experiments were conducted over a range of TCO values. Adult rats (n = 30) were anesthetized with sodium pentobarbital (35 mg/kg) and randomly assigned to one of six equal groups.

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Several reports in the literature suggest a relationship between lead intoxication and thermoregulatory capacity. To investigate the effects of lead on the control of body temperature, mice of the BALB/c strain were injected intraperitoneally with lead acetate (0 to 100 mg/kg) while colonic temperature was measured 30, 60, and 90 min post-injection at ambient temperatures (Ta) of 20 and 30 degrees C. Lead acetate caused a transient hypothermia, an effect which was augmented at cooler Ta's.

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