Showing papers by "University of Maryland, Baltimore published in 2004"

Pathogenic Escherichia coli

Abstract: Few microorganisms are as versatile as Escherichia coli. An important member of the normal intestinal microflora of humans and other mammals, E. coli has also been widely exploited as a cloning host in recombinant DNA technology. But E. coli is more than just a laboratory workhorse or harmless intestinal inhabitant; it can also be a highly versatile, and frequently deadly, pathogen. Several different E. coli strains cause diverse intestinal and extraintestinal diseases by means of virulence factors that affect a wide range of cellular processes.

Effect of Intensive Compared With Moderate Lipid-Lowering Therapy on Progression of Coronary Atherosclerosis A Randomized Controlled Trial

Abstract: ContextStatin drugs reduce both atherogenic lipoproteins and cardiovascular morbidity and mortality. However, the optimal strategy and target level for lipid reduction remain uncertain.ObjectiveTo compare the effect of regimens designed to produce intensive lipid lowering or moderate lipid lowering on coronary artery atheroma burden and progression.Design, Setting, and PatientsDouble-blind, randomized active control multicenter trial (Reversal of Atherosclerosis with Aggressive Lipid Lowering [REVERSAL]) performed at 34 community and tertiary care centers in the United States comparing the effects of 2 different statins administered for 18 months. Intravascular ultrasound was used to measure progression of atherosclerosis. Between June 1999 and September 2001, 654 patients were randomized and received study drug; 502 had evaluable intravascular ultrasound examinations at baseline and after 18 months of treatment.InterventionsPatients were randomly assigned to receive a moderate lipid-lowering regimen consisting of 40 mg of pravastatin or an intensive lipid-lowering regimen consisting of 80 mg of atorvastatin.Main Outcome MeasuresThe primary efficacy parameter was the percentage change in atheroma volume (follow-up minus baseline).ResultsBaseline low-density lipoprotein cholesterol level (mean, 150.2 mg/dL [3.89 mmol/L] in both treatment groups) was reduced to 110 mg/dL (2.85 mmol/L) in the pravastatin group and to 79 mg/dL (2.05 mmol/L) in the atorvastatin group (P<.001). C-reactive protein decreased 5.2% with pravastatin and 36.4% with atorvastatin (P<.001). The primary end point (percentage change in atheroma volume) showed a significantly lower progression rate in the atorvastatin (intensive) group (P = .02). Similar differences between groups were observed for secondary efficacy parameters, including change in total atheroma volume (P = .02), change in percentage atheroma volume (P<.001), and change in atheroma volume in the most severely diseased 10-mm vessel subsegment (P<.01). For the primary end point, progression of coronary atherosclerosis occurred in the pravastatin group (2.7%; 95% confidence interval [CI], 0.2% to 4.7%; P = .001) compared with baseline. Progression did not occur in the atorvastatin group (−0.4%; CI −2.4% to 1.5%; P = .98) compared with baseline.ConclusionsFor patients with coronary heart disease, intensive lipid-lowering treatment with atorvastatin reduced progression of coronary atherosclerosis compared with pravastatin. Compared with baseline values, patients treated with atorvastatin had no change in atheroma burden, whereas patients treated with pravastatin showed progression of coronary atherosclerosis. These differences may be related to the greater reduction in atherogenic lipoproteins and C- reactive protein in patients treated with atorvastatin.

Aerosol properties over bright-reflecting source regions

Abstract: Retrieving aerosol properties from satellite remote sensing over a bright surface is a challenging problem in the research of atmospheric and land applications. In this paper we propose a new approach to retrieve aerosol properties over surfaces such as arid, semiarid, and urban areas, where the surface reflectance is usually very bright in the red part of visible spectrum and in the near infrared, but is much darker in the blue spectral region (i.e., wavelength <500 nm). In order to infer atmospheric properties from these data, a global surface reflectance database of 0.1/spl deg/ latitude by 0.1/spl deg/ longitude resolution was constructed over bright surfaces for visible wavelengths using the minimum reflectivity technique (e.g., finding the clearest scene during each season for a given location). The aerosol optical thickness and aerosol type are then determined simultaneously in the algorithm using lookup tables to match the satellite observed spectral radiances. Examples of aerosol optical thickness derived using this algorithm over the Sahara Desert and Arabian Peninsula reveal various dust sources, which are important contributors to airborne dust transported over long distances. Comparisons of the satellite inferred aerosol optical thickness and the values from ground-based Aerosol Robotic Network (AERONET) sun/sky radiometer measurements indicate good agreement (i.e., within 30%) over the sites in Nigeria and Saudi Arabia. This new algorithm, when applied to Moderate Resolution Imaging Spectroradiometer (MODIS), Sea-viewing Wide Field of view Sensor (SeaWiFS), and Global Imager (GLI) satellite data, will provide high spatial resolution (/spl sim/1 km) global information of aerosol optical thickness over bright surfaces on a daily basis.

The Schizophrenia Patient Outcomes Research Team (PORT): Updated Treatment Recommendations 2003

Abstract: Since publication of the original Schizophrenia Patient Outcomes Research Team (PORT) treatment recommendations in 1998, considerable scientific advances have occurred in our knowledge about how to help persons with schizophrenia. Today an even stronger body of research supports the scientific basis of treatment. This evidence, taken in its entirety, points to the value of treatment approaches combining medications with psychosocial treatments, including psychological interventions, family interventions, supported employment, assertive community treatment, and skills training. The most significant advances lie in the increased options for pharmacotherapy, with the introduction of second generation antipsychotic medications, and greater confidence and specificity in the application of psychosocial interventions. Currently available treatment technologies, when appropriately applied and accessible, should provide most patients with significant relief from psychotic symptoms and improved opportunities to lead more fulfilling lives in the community. Nonetheless, major challenges remain, including the need for (1) better knowledge about the underlying etiologies of the neurocognitive impairments and deficit symptoms that account for much of the disability still associated with schizophrenia; (2) treatments that more directly address functional impairments and that promote recovery; and (3) approaches that facilitate access to scientifically based treatments for patients, the vast majority of whom currently do not have such access.

Mitochondrial α-Ketoglutarate Dehydrogenase Complex Generates Reactive Oxygen Species

Abstract: Mitochondria-produced reactive oxygen species (ROS) are thought to contribute to cell death caused by a multitude of pathological conditions. The molecular sites of mitochondrial ROS production are not well established but are generally thought to be located in complex I and complex III of the electron transport chain. We measured H2O2 production, respiration, and NADPH reduction level in rat brain mitochondria oxidizing a variety of respiratory substrates. Under conditions of maximum respiration induced with either ADP or carbonyl cyanide p-trifluoromethoxyphenylhydrazone,α-ketoglutarate supported the highest rate of H2O2 production. In the absence of ADP or in the presence of rotenone, H2O2 production rates correlated with the reduction level of mitochondrial NADPH with various substrates, with the exception of α-ketoglutarate. Isolated mitochondrial α-ketoglutarate dehydrogenase (KGDHC) and pyruvate dehydrogenase (PDHC) complexes produced superoxide and H2O2. NAD+ inhibited ROS production by the isolated enzymes and by permeabilized mitochondria. We also measured H2O2 production by brain mitochondria isolated from heterozygous knock-out mice deficient in dihydrolipoyl dehydrogenase (Dld). Although this enzyme is a part of both KGDHC and PDHC, there was greater impairment of KGDHC activity in Dld-deficient mitochondria. These mitochondria also produced significantly less H2O2 than mitochondria isolated from their littermate wild-type mice. The data strongly indicate that KGDHC is a primary site of ROS production in normally functioning mitochondria.

Effectiveness of acupuncture as adjunctive therapy in osteoarthritis of the knee: a randomized, controlled trial.

Abstract: Background Evidence on the efficacy of acupuncture for reducing the pain and dysfunction of osteoarthritis is equivocal. Objective To determine whether acupuncture provides greater pain relief and improved function compared with sham acupuncture or education in patients with osteoarthritis of the knee. Design Randomized, controlled trial. Setting Two outpatient clinics (an integrative medicine facility and a rheumatology facility) located in academic teaching hospitals and 1 clinical trials facility. Patients 570 patients with osteoarthritis of the knee (mean age [+/-SD], 65.5 +/- 8.4 years). Intervention 23 true acupuncture sessions over 26 weeks. Controls received 6 two-hour sessions over 12 weeks or 23 sham acupuncture sessions over 26 weeks. Measurements Primary outcomes were changes in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and function scores at 8 and 26 weeks. Secondary outcomes were patient global assessment, 6-minute walk distance, and physical health scores of the 36-Item Short-Form Health Survey (SF-36). Results Participants in the true acupuncture group experienced greater improvement in WOMAC function scores than the sham acupuncture group at 8 weeks (mean difference, -2.9 [95% CI, -5.0 to -0.8]; P = 0.01) but not in WOMAC pain score (mean difference, -0.5 [CI, -1.2 to 0.2]; P = 0.18) or the patient global assessment (mean difference, 0.16 [CI, -0.02 to 0.34]; P > 0.2). At 26 weeks, the true acupuncture group experienced significantly greater improvement than the sham group in the WOMAC function score (mean difference, -2.5 [CI, -4.7 to -0.4]; P = 0.01), WOMAC pain score (mean difference, -0.87 [CI, -1.58 to -0.16];P = 0.003), and patient global assessment (mean difference, 0.26 [CI, 0.07 to 0.45]; P = 0.02). Limitations At 26 weeks, 43% of the participants in the education group and 25% in each of the true and sham acupuncture groups were not available for analysis. Conclusions Acupuncture seems to provide improvement in function and pain relief as an adjunctive therapy for osteoarthritis of the knee when compared with credible sham acupuncture and education control groups.

Repetitive Bilateral Arm Training and Motor Cortex Activation in Chronic Stroke: A Randomized Controlled Trial

Abstract: Hemiparesis represents the dominant functionally limiting symptom in 80% of patients with acute stroke.1 Within 2 to 5 months after a stroke, patients recover a variable degree of function, depending on the magnitude of the initial deficit.1 Several studies have demonstrated that recovery is associated with reorganization of central nervous system networks.2,3 Functional brain imaging of paretic movement during the recovery period has shown recruitment of cortex immediately adjacent to the stroke cavity along with intact cortical areas within the lesioned and in the uninjured contralesional hemisphere.4,5 The pattern of recruitment depends on the severity of impairment,6 lesion location,7 and time since stroke.8 The factors that initiate and maintain cortical reorganization are not known. Imaging data suggest that circuitry in motor cortices on both sides of the brain is modified during recovery.2 Even with traditional rehabilitation therapy, 50% to 95% of stroke survivors remain impaired.9-11 For some patients, recently developed repetitive active training therapies provide additional benefit.12 Bilateral arm training with rhythmic auditory cueing (BATRAC), a rehabilitation therapy based on the concept that bilateral movement permits interhemispheric facilitation of the limbs,13 is one such intervention. We previously showed that BATRAC improves arm function in chronic stroke survivors with fixed upper extremity deficits.14 We hypothesized that BATRAC may be associated with reorganization of brain regions involved in motor control.

Association of timing of surgery for hip fracture and patient outcomes.

Abstract: ContextPrevious studies of surgical timing in patients with hip fracture have yielded conflicting findings on mortality and have not focused on functional outcomes.ObjectiveTo examine the association of timing of surgical repair of hip fracture with function and other outcomes.DesignProspective cohort study including analyses matching cases of early (≤24 hours) and late (>24 hours) surgery with propensity scores and excluding patients who might not be candidates for early surgery.SettingFour hospitals in the New York City metropolitan area.ParticipantsA total of 1206 patients aged 50 years or older admitted with hip fracture over 29 months, ending December 1999.Main Outcome MeasuresFunction (using the Functional Independence Measure), survival, pain, and length of stay (LOS).ResultsOf the patients treated with surgery (n = 1178), 33.8% had surgery within 24 hours. Earlier surgery was not associated with improved mortality (hazard ratio, 0.75; 95% confidence interval [CI], 0.52-1.08) or improved locomotion (difference of −0.04 points; 95% CI, –0.49 to 0.39). Earlier surgery was associated with fewer days of severe and very severe pain (difference of −0.22 days; 95% CI, −0.41 to −0.03) and shorter LOS by 1.94 days (P<.001), but postoperative pain and LOS after surgery did not differ. Analyses with propensity scores yielded similar results. When the cohort included only patients who were medically stable at admission and therefore eligible for early surgery, the results were unchanged except that early surgery was associated with fewer major complications (odds ratio, 0.26; 95% CI, 0.07-0.95).ConclusionsEarly surgery was not associated with improved function or mortality, but it was associated with reduced pain and LOS and probably major complications among patients medically stable at admission. Additional research is needed on whether functional outcomes may be improved. In the meantime, patients with hip fracture who are medically stable should receive early surgery when possible.

Socioeconomic Position and Major Mental Disorders

Abstract: Psychiatric epidemiologists were among the first to use the term “social epidemiology” (1), and the role of the social environment in the etiology and course of major mental disorders continues to be investigated (2–5). A number of reviews published in the late 1990s documented the associations between socioeconomic position (SEP) and specific mental disorders (6–9); in 2003, a comprehensive meta-analysis of the research on SEP and depression (10) concluded that both prevalence and incidence studies show that persons of low SEP (i.e., low educational and low income levels) are at a higher risk of depression.

From the archives of the AFIP: benign musculoskeletal lipomatous lesions.

Abstract: Benign lipomatous lesions involving soft tissue are common musculoskeletal masses that are classified into nine distinct diagnoses: lipoma, lipomatosis, lipomatosis of nerve, lipoblastoma or lipoblastomatosis, angiolipoma, myolipoma of soft tissue, chondroid lipoma, spindle cell lipoma and pleomorphic lipoma, and hibernoma. Soft-tissue lipoma accounts for almost 50% of all soft-tissue tumors. Radiologic evaluation is diagnostic in up to 71% of cases. These lesions are identical to subcutaneous fat on computed tomographic (CT) and magnetic resonance (MR) images and may contain thin septa. Lipomatosis represents a diffuse overgrowth of mature fat affecting either subcutaneous tissue, muscle or nerve, and imaging is needed to evaluate lesion extent. Lipoblastoma is a tumor of immature fat occurring in young children, and imaging features may reveal a mixture of fat and nonadipose tissue. Angiolipoma, myolipoma, and chondroid lipoma are rare lipomatous lesions that are infrequently imaged. Spindle cell and pleomorphic lipoma appear as a subcutaneous lipomatous mass in the posterior neck or shoulder, with frequent nonadipose components. Hibernoma appears as a lipomatous mass with serpentine vascular elements. Benign lipomatous lesions affecting bone, joint, or tendon sheath include intraosseous lipoma, parosteal lipoma, liposclerosing myxofibrous tumor, discrete lipoma of joint or tendon sheath, and lipoma arborescens. Intraosseous and parosteal lipoma have a pathognomonic CT or MR appearance, with fat in the marrow space or on the bone surface, respectively. Liposclerosing myxofibrous tumor is a rare intermixed histologic lesion commonly located in the medullary canal of the intertrochanteric femur. Benign lipomatous lesions may occur focally in a joint or tendon sheath or with diffuse villonodular proliferation in the synovium (lipoma arborescens) and are diagnosed based on location and identification of fat. Understanding the spectrum of appearances of the various benign musculoskeletal lipomatous lesions improves radiologic assessment and is vital for optimal patient management.

MHC Class I Peptides as Chemosensory Signals in the Vomeronasal Organ

Abstract: The mammalian vomeronasal organ detects social information about gender, status, and individuality. The molecular cues carrying this information remain largely unknown. Here, we show that small peptides that serve as ligands for major histocompatibility complex (MHC) class I molecules function also as sensory stimuli for a subset of vomeronasal sensory neurons located in the basal Gao- and V2R receptor-expressing zone of the vomeronasal epithelium. In behaving mice, the same peptides function as individuality signals underlying mate recognition in the context of pregnancy block. MHC peptides constitute a previously unknown family of chemosensory stimuli by which MHC genotypic diversity can influence social behavior.

Osteoporosis and Fracture Risk in Women of Different Ethnic Groups

Abstract: Osteoporosis and 1-year fracture risk were studied in 197,848 postmenopausal American women from five ethnic groups. Weight explained differences in BMD, except among blacks, who had the highest BMD. One SD decrease in BMD predicted a 50% increased fracture risk in each group. Despite similar relative risks, absolute fracture rates differed. Introduction: Most information about osteoporosis comes from studies of white women. This study describes the frequency of osteoporosis and the association between BMD and fracture in women from five ethnic groups. Materials and Methods: This study was made up of a cohort of 197,848 community-dwelling postmenopausal women (7784 blacks, 1912 Asians, 6973 Hispanics, and 1708 Native Americans) from the United States, without known osteoporosis or a recent BMD test. Heel, forearm, or finger BMD was measured, and risk factor information was obtained; 82% were followed for 1 year for new fractures. BMD and fracture rates were compared, adjusting for differences in covariates. Results: By age 80, more than one-fifth of women in each ethnic group had peripheral BMD T scores <−2.5. Black women had the highest BMD; Asian women had the lowest. Only the BMD differences for blacks were not explained by differences in weight. After 1 year, 2414 new fractures of the spine, hip, forearm, wrist, or rib were reported. BMD at each site predicted fractures equally well within each ethnic group. After adjusting for BMD, weight, and other covariates, white and Hispanic women had the highest risk for fracture (relative risk ‘RR’ 1.0 ‘referent group’ and 0.95, 95% CI, 0.76, 1.20, respectively), followed by Native Americans (RR, 0.87; 95% CI, 0.57, 1.32), blacks (RR, 0.52; 95% CI, 0.38, 0.70), and Asian Americans (RR, 0.32; 95% CI, 0.15, 0.66). In age- and weight-adjusted models, each SD decrease in peripheral BMD predicted a 1.54 times increased risk of fracture in each ethnic group (95% CI, 1.48-1.61). Excluding wrist fractures, the most common fracture, did not materially change associations. Conclusions: Ethnic differences in BMD are strongly influenced by body weight; fracture risk is strongly influenced by BMD in each group. Ethnic differences in absolute fracture risk remain, which may warrant ethnic-specific clinical recommendations.

Food Insecurity Is Associated with Adverse Health Outcomes among Human Infants and Toddlers

Abstract: The U.S. Household Food Security Scale, developed with federal support for use in national surveys, is an effective research tool. This study uses these new measures to examine associations between food insecurity and health outcomes in young children. The purpose of this study was to determine whether household food insecurity is associated with adverse health outcomes in a sentinel population ages < or = 36 mo. We conducted a multisite retrospective cohort study with cross-sectional surveys at urban medical centers in 5 states and Washington DC, August 1998-December 2001. Caregivers of 11,539 children ages < or = 36 mo were interviewed at hospital clinics and emergency departments (ED) in central cities. Outcome measures included child's health status, hospitalization history, whether child was admitted to hospital on day of ED visit (for subsample interviewed in EDs), and a composite growth-risk variable. In this sample, 21.4% of households were food insecure (6.8% with hunger). In a logistic regression, after adjusting for confounders, food-insecure children had odds of "fair or poor" health nearly twice as great [adjusted odds ratio (AOR) = 1.90, 95% CI = 1.66-2.18], and odds of being hospitalized since birth almost a third larger (AOR = 1.31, 95% CI = 1.16-1.48) than food-secure children. A dose-response relation appeared between fair/poor health status and severity of food insecurity. Effect modification occurred between Food Stamps and food insecurity; Food Stamps attenuated (but did not eliminate) associations between food insecurity and fair/poor health. Food insecurity is associated with health problems for young, low-income children. Ensuring food security may reduce health problems, including the need for hospitalizations.

Morphologic Findings of Coronary Atherosclerotic Plaques in Diabetics. A Postmortem Study

Abstract: Objective— Coronary atherosclerotic plaque composition of diabetic subjects and localization of receptor for advanced glycation end products (RAGE) and its ligands have not been extensively studied. Methods and Results— Hearts from diabetic subjects and age, race, and sex-matched nondiabetic subjects dying suddenly were examined. Coronary arteries were dissected and lesions were evaluated for plaque burden, necrotic core size, and inflammatory infiltrate. The expression of RAGE, the RAGE-binding protein (S100-A12, EN-RAGE), and cell death (apoptosis) were also determined. Lesions from type II diabetic subjects had larger mean necrotic cores (P=0.01) and greater total and distal plaque load (P<0.001) than nondiabetic subjects. Necrotic core size correlated positively with diabetic status, independent of other risk factors. Intimal staining for macrophages, T-cells, and HLA-DR was also significantly greater in diabetic subjects (P=0.03, P=0.003, and P<0.0001), respectively. The association of increased macr...

T cells express a phagocyte-type NADPH oxidase that is activated after T cell receptor stimulation

Abstract: T cell receptor (TCR) stimulation induces rapid generation of reactive oxygen species, although the mechanisms for this are unclear. Here we found that T cells expressed a functional phagocyte-type nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. TCR crosslinking induced oxidase activation through the recruitment of preformed Fas ligand and Fas. TCR stimulation induced three separable events generating reactive oxygen species: rapid hydrogen peroxide production independent of Fas or NADPH oxidase; sustained hydrogen peroxide production dependent on both Fas and NADPH oxidase; and delayed superoxide production that was dependent on Fas ligand and Fas yet independent of NADPH oxidase. NADPH oxidase-deficient T cells showed enhanced activation of the kinase Erk and a relative increase in T helper type 1 cytokine secretion. Thus, mature T cells express a phagocyte-type NADPH oxidase that regulates elements of TCR signaling.

Clinical Microbiology of Bacterial and Fungal Sepsis in Very-Low-Birth-Weight Infants

Abstract: Twenty percent of very-low-birth-weight (<1500 g) preterm infants experience a serious systemic infection, and despite advances in neonatal intensive care and antimicrobials, mortality is as much as threefold higher for these infants who develop sepsis than their counterparts without sepsis during their hospitalization. Outcomes may be improved by preventative strategies, earlier and accurate diagnosis, and adjunct therapies to combat infection and protect the vulnerable preterm infant during an infection. Earlier diagnosis on the basis of factors such as abnormal heart rate characteristics may offer the ability to initiate treatment prior to the onset of clinical symptoms. Molecular and adjunctive diagnostics may also aid in diagnosing invasive infection when clinical symptoms indicate infection but no organisms are isolated in culture. Due to the high morbidity and mortality, preventative and adjunctive therapies are needed. Prophylaxis has been effective in preventing early-onset group B streptococcal sepsis and late-onset Candida sepsis. Future research in prophylaxis using active and passive immunization strategies offers prevention without the risk of resistance to antimicrobials. Identification of the differences in neonatal intensive care units with low and high infection rates and implementation of infection control measures remain paramount in each neonatal intensive care unit caring for preterm infants.