Publications by authors named "Fields C"

Recent risk assessments of environmental perchlorate have been subject to much debate. A particular concern is whether appropriate susceptible sub-populations have been identified. Iodine-deficient pregnant women, especially vegetarians, have been proposed as such a potential susceptible sub-population, but there is no evidence of iodine deficiency in the US population and the adequacy of iodine nutrition has not been studied in US vegetarians.

View Article and Find Full Text PDF

PyrR is a protein that regulates the expression of genes and operons of pyrimidine nucleotide biosynthesis (pyr genes) in many bacteria. PyrR acts by binding to specific sequences on pyr mRNA and causing transcriptional attenuation when intracellular levels of uridine nucleotides are elevated. PyrR from Bacillus subtilis has been purified and extensively studied.

View Article and Find Full Text PDF

We report a patient treated for infection of an ascending aorta to bilateral common carotid artery bypass graft. The superficial femoral arteries were used for the reconstruction after local treatment failed. The patient is free from infection and the grafts are patent 4 years after operation.

View Article and Find Full Text PDF

Background: Violence is a large contributor to morbidity and mortality among adolescents. Most studies assessing markers for violent injury are cross-sectional. To guide intervention, we conducted a case-control study to explore factors associated with assault injury and locations to reach at-risk adolescents.

View Article and Find Full Text PDF

Mice represent a valuable species for studies of development and disease. With the availability of transgenic models for retinal degeneration in this species, information regarding development and structure of mouse retina has become increasingly important. Of special interest is the differentiation and synaptogenesis of photoreceptors since these cells are predominantly involved in hereditary retinal degenerations.

View Article and Find Full Text PDF

Sulfated steroids like pregnenolone sulfate (PS) are found endogenously in the central nervous system where they may modulate GABAA receptors. Understanding the mechanism of steroid inhibition is important for understanding the conditions under which endogenous steroids modulate GABAA receptor function, assessing their potential clinical utility, and for evaluating sulfated steroids as probes of receptor behaviour. Some previous studies suggest that sulfated steroid inhibition exhibits activation dependence, whilst other studies suggest only slow, time-dependent inhibition, perhaps reflecting slow PS association with receptors.

View Article and Find Full Text PDF

Purpose: The purpose of this study was to evaluate the extent (luminal coverage) of the endothelial cell (EC) lining/neointimal development and the thromboresistance of electrostatically EC seeded small diameter e-PTFE vascular grafts.

Methods: This evaluation consisted of harvesting autologous, canine jugular vein ECs, electrostatically EC seeding the e-PTFE grafts (4 mm GORE-TEX, Length = 6 cm), implanting the grafts in a canine femoral artery model for six weeks, and excising the graft for histological and scanning electron microscopy evaluations.

Results: The results of the histological evaluation (mid-graft region only) indicated that the electrostatic EC seeding significantly affected neointimal development (p < 0.

View Article and Find Full Text PDF

We evaluated the extent (luminal coverage) of the endothelial cell (EC) lining/neointimal development and the thromboresistance of electrostatically EC seeded small diameter ChronoFlex-polyurethane vascular grafts. The evaluation consisted of harvesting autologous, canine jugular vein ECs, electrostatically seeding the polyurethane grafts (4-mm I.D.

View Article and Find Full Text PDF

Endogenous neurosteroids have rapid actions on ion channels, particularly GABA(A) receptors, which are potentiated by nanomolar concentrations of 3alpha-hydroxypregnane neurosteroids. Previous evidence suggests that 3beta-hydroxypregnane steroids may competitively antagonize potentiation induced by their 3alpha diastereomers. Because of the potential importance of antagonists as experimental and clinical tools, we characterized the functional effect of 3beta-hydroxysteroids.

View Article and Find Full Text PDF

Purpose: Migration of retinal pigment epithelial (RPE) cells can be triggered by disruption of the RPE monolayer or injury to the neural retina. Migrating cells may re-establish a confluent monolayer, or they may invade the neural retina and disrupt visual function. The purpose of this study was to examine the role of endogenous polyamines in mechanisms of RPE migration.

View Article and Find Full Text PDF

Upper extremity vascular injuries are common in trauma. The mortality rate from these injuries is quite low; however, the morbidity rate is quite significant. Prompt diagnosis and treatment can reduce the amputation rate for these injuries to minimal.

View Article and Find Full Text PDF

Purpose: The purpose of this study was to evaluate the persistence of electrostatically seeded endothelial cells (ECs) lining an expanded polytetrafluorethylene (e-PTFE) graft after one week exposure to in vivo circulation in a canine femoral artery bypass model. This was accomplished by visualizing the PKH 26 (red fluorescent) label placed in the EC membranes prior to the seeding procedure. Furthermore, this study was performed to confirm that the source of the ECs lining the graft were those from the initial inoculum.

View Article and Find Full Text PDF

Giant bullae occur most often in individuals who chronically inhale tobacco smoke. The natural history of these bullae is unpredictable, although the majority of them increase gradually in size and cause worsening respiratory function. Complete spontaneous resolution of a giant bulla is a rare occurrence, with only eight cases reported in English literature.

View Article and Find Full Text PDF

Simvastatin, a hydroxymethyl glutarate coenzyme A (HMG-CoA) reductase inhibitor, is a commonly used cholesterol lowering agent. The long-term safety profile of simvastatin, established over ten-years of clinical use, is excellent. Both rhabdomyolysis and hepatitis, however, are recognized toxic effects of this medication, and generally occur when the patients are taking more than 40 mg of simvastatin a day.

View Article and Find Full Text PDF

Pasteurella multocida typically causes cutaneous infections in humans following animal bites or scratches. Primary pulmonary disease, however, can occur in humans after inhalation of airborne particles or by aspiration of colonized or infected nasopharyngeal secretions containing this organism. Symptoms of P.

View Article and Find Full Text PDF

Study Objective: Adolescent homicide rates are decreasing nationally for unclear reasons. We explore changes in intentional injury morbidity and mortality within the context of other injuries and specific causes.

Methods: We performed surveillance of hospital, medical examiner, and vital records for nonfatal injury among adolescents age 10 to 19 years living in the District of Columbia from June 15, 1996, to June 15, 1998, and fatal injury from 1989 to 1998.

View Article and Find Full Text PDF

Influenza A pneumonia accounts for a significant number of the community-acquired pneumonias in the United States. While myalgia is a common complaint in influenza A infection, few cases of rhabdomyolysis associated with this virus have been described. Although it has been recently recognized that rhabdomyolysis complicating certain bacterial pneumonias has important prognostic implications, rhabdomyolysis in the setting of influenza A pneumonia does not appear to carry the same prognostic significance.

View Article and Find Full Text PDF

Tracheobronchomegaly (TBM) is a disorder of the major airways characterized by an enlargement of the trachea and main stem bronchi. It is thought to result from a congenital connective tissue defect that results in the trachea and main bronchi becoming flaccid. Although TBM is considered rare, it may be more common than is generally recognized, and may be a seldom-diagnosed cause of chronic lung disease.

View Article and Find Full Text PDF

Background: Studies suggest that the selective use of anaerobic blood cultures may represent a more cost-effective laboratory approach when anaerobic bacterial infection is suspected.

Methods: A 5-year retrospective study was done at a Veterans' Affairs hospital to determine the utility of routinely including anaerobic blood culture when sampling for bacteremia.

Results: A total of 22,075 anaerobic blood cultures were collected from our adult population.

View Article and Find Full Text PDF

Objective: To evaluate the safety, tolerability, and anti-HIV activity of ritonavir-nelfinavir (RTV-NFV).

Design: Single-site, open-label, nonrandomized, multiple-dose trial of RTV combined with two doses of NFV in protease inhibitor (PI)-naive, HIV-infected patients.

Methods: Mean baseline HIV RNA was 39,500 copies/ml; mean baseline CD4 count was 323 cells/mm3.

View Article and Find Full Text PDF

Patients with common variable immunodeficiency (CVID) are occasionally recognized to have a concurrent noncaseating granulomatous disease. The granulomatous disease (GD) associated with CVID shares many clinical properties typical of sarcoidosis. Some investigators speculate that the GD-CVID is actually sarcoidosis that is expressed atypically because of the patient's immunodeficiency.

View Article and Find Full Text PDF

Primary tracheal lipomas are extremely rare neoplasms. The typical patient is a middle-aged man with complaints of cough and shortness of breath. Often, the diagnosis is delayed, and patients are treated for asthma or bronchitis.

View Article and Find Full Text PDF