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Biomedical subjects

D Levine

Publications and source records attributed to D Levine.

At least 19 recordsLinked to original sources
PubMed2006

The effects of esomeprazole combined with aspirin or rofecoxib on prostaglandin E2 production in patients with Barrett's oesophagus.

BACKGROUND: Reducing mucosal cyclo-oxygenase-2 and prostaglandin E(2) production and suppressing intraoesophageal acid may be effective chemopreventive strategies in patients with Barrett's oesophagus. AIM: To compare the effects of aspirin and rofecoxib when administered with esomeprazole on prostaglandin E(2) production, cyclo-oxygenase-2 expression and proliferating cell nuclear antigen expression in patients with Barrett's oesophagus. METHODS: This exploratory, multicentre, randomized, open-label, four-way crossover study in 45 patients with Barrett's oesophagus evaluated prostaglandin E(2) content, proliferating cell nuclear antigen expression, and cyclo-oxygenase-2 expression after 10 days of sequential treatments with: esomeprazole 40 mg twice daily plus aspirin 325 mg once daily (E40 b.d. + A325); E40 b.d. plus rofecoxib 25 mg once daily (E40 b.d. + R25); E40 b.d.; and rofecoxib 25 mg once daily (R25). RESULTS: Prostaglandin E(2) content reduction in Barrett's oesophagus tissue was significantly greater with E40 b.d. + A325 compared with E40 b.d. + R25, E40 b.d. or R25 (P < 0.05). All treatments containing E40 b.d. significantly decreased proliferating cell nuclear antigen expression from baseline (P < 0.05). None of the treatments significantly reduced cyclo-oxygenase-2 expression. CONCLUSIONS: The combined treatment of esomeprazole 40 mg b.d. and aspirin 325 mg significantly decreased mucosal prostaglandin E(2) content and all treatments containing esomeprazole significantly reduced proliferating cell nuclear antigen expression in patients with Barrett's oesophagus.

Adult↗
PubMed2004

Fetal magnetic resonance imaging.

Fast magnetic resonance imaging (MRI) has revolutionized our ability to image the fetus. Using fast scanning techniques, individual images are obtained in 300-400 ms, allowing for imaging of the fetus without sedation. MRI is most useful for evaluation of the anomalous fetal central nervous system, for further characterization of complex anomalies not fully elucidated by ultrasound and for evaluation of patients desiring fetal surgery. This review describes the history of fetal MRI, discusses current applications and mentions developments on the horizon.

Central Nervous System↗
PubMed2003

Esomeprazole resolves chronic heartburn in patients without erosive oesophagitis.

BACKGROUND: Patients with chronic heartburn but with no endoscopic evidence of erosive oesophagitis require gastric acid suppression to relieve symptoms. AIM: To assess the efficacy and safety of esomeprazole in patients with frequent heartburn for >or = 6 months and no evidence of erosive oesophagitis on endoscopy. METHODS: Two randomized, double-blind, 4-week, multi-centre trials with identical methodology compared once-daily esomeprazole, 40 mg (n = 241) or 20 mg (n = 234), with placebo (n = 242) for the rigorous end-point of complete resolution of heartburn. Secondary end-points included the percentage of heartburn-free days and the time to first and sustained resolution of heartburn. RESULTS: Patients treated with either dose of esomeprazole were two to three times more likely to achieve complete resolution of heartburn than patients treated with placebo (P < 0.001). The percentage of heartburn-free days was significantly higher with esomeprazole 40 mg (63%, 66%) or 20 mg (63%, 68%) than with placebo (46%, 36%; P < or = 0.001) in each of the two studies. Esomeprazole was associated with a significantly shorter mean time to first (6-7 days) and sustained (12-17 days) resolution of heartburn compared with placebo (first, 10-12 days; sustained, 21-22 days; P < or = 0.008). The spectrum and frequency of adverse events with esomeprazole were similar to those with placebo. CONCLUSIONS: Esomeprazole, at daily doses of 40 mg or 20 mg, is effective and safe for the treatment of chronic heartburn in patients without erosive oesophagitis.

Adult↗
PubMed2002

Test characteristics of the urine Gram stain in infants <or= 60 days of age with fever.

OBJECTIVE: The utility of the Gram stain for the preliminary diagnosis of urinary tract infections (UTI) in infants or= 38.0 degrees C presenting to a pediatric emergency department during 2 consecutive winter seasons. Single pathogen growth of >or= 10(4) cfu/mL from a catheterized specimen and >or= 10(3) cfu/mL from a suprapubic specimen was considered positive. A positive Gram stain was defined as the identification of any organisms. Urinalysis was tested for the presence of nitrites and for leukocyte esterase (LE). Urine microscopy was analyzed for white blood cells per high power field (WBC/hpf). RESULTS: Fourteen of 246 patients were excluded; 11 because no Gram stain was completed. Of the remaining 232 patients, Gram stain had a sensitivity of 85.2% (95% CI 71.9-98.6%), a specificity of 99.0% (95% CI 97.7-100%), a likelihood ratio for a positive test of 87.3 (95% CI 21.8-349.9), and a likelihood ratio for a negative test of 0.15 (95% CI 0.06-0.37). There were 193 specimens for which a Gram stain and a complete UA and microscopy were completed and compared. Urine microscopy had a lower sensitivity and specificity than Gram stain for both >or= 5 WBC/hpf and >or= 10 WBC/hpf. In addition to the Gram stain, a dipstick negative for nitrites and LE had a low negative likelihood ratio (0.16), useful for decreasing the likelihood of a UTI. CONCLUSIONS: The Gram stain has excellent test characteristics for the preliminary diagnosis of a UTI in febrile infants. Patient disposition and therapy will likely change if clinical protocols and guidelines use the Gram stain rather than urine microscopy for preliminary diagnosis of UTI in infants.

Female↗
PubMed2001

Granular flow down an inclined plane: Bagnold scaling and rheology.

We have performed a systematic, large-scale simulation study of granular media in two and three dimensions, investigating the rheology of cohesionless granular particles in inclined plane geometries, i.e., chute flows. We find that over a wide range of parameter space of interaction coefficients and inclination angles, a steady-state flow regime exists in which the energy input from gravity balances that dissipated from friction and inelastic collisions. In this regime, the bulk packing fraction (away from the top free surface and the bottom plate boundary) remains constant as a function of depth z, of the pile. The velocity profile in the direction of flow vx(z) scales with height of the pile H, according to vx(z) proportional to H(alpha), with alpha=1.52+/-0.05. However, the behavior of the normal stresses indicates that existing simple theories of granular flow do not capture all of the features evidenced in the simulations.

Journal Article↗
PubMed2001

Association between blood pressure level and the risk of myocardial infarction, stroke, and total mortality: the cardiovascular health study.

BACKGROUND: Recent reports have drawn attention to the importance of pulse pressure as a predictor of cardiovascular events. Pulse pressure is used neither by clinicians nor by guidelines to define treatable levels of blood pressure. METHODS: In the Cardiovascular Health Study, 5888 adults 65 years and older were recruited from 4 US centers. At baseline in 1989-1990, participants underwent an extensive examination, and all subsequent cardiovascular events were ascertained and classified. RESULTS: At baseline, 1961 men and 2941 women were at risk for an incident myocardial infarction or stroke. During follow-up that averaged 6.7 years, 572 subjects had a coronary event, 385 had a stroke, and 896 died. After adjustment for potential confounders, systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse pressure were directly associated with the risk of incident myocardial infarction and stroke. Only SBP was associated with total mortality. Importantly, SBP was a better predictor of cardiovascular events than DBP or pulse pressure. In the adjusted model for myocardial infarction, a 1-SD change in SBP, DBP, and pulse pressure was associated with hazard ratios (95% confidence intervals) of 1.24 (1.15-1.35), 1.13 (1.04-1.22), and 1.21 (1.12-1.31), respectively; and adding pulse pressure or DBP to the model did not improve the fit. For stroke, the hazard ratios (95% confidence intervals) were 1.34 (1.21-1.47) with SBP, 1.29 (1.17-1.42) with DBP, and 1.21 (1.10-1.34) with pulse pressure. The association between blood pressure level and cardiovascular disease risk was generally linear; specifically, there was no evidence of a J-shaped relationship. In those with treated hypertension, the hazard ratios for the association of SBP with the risks for myocardial infarction and stroke were less pronounced than in those without treated hypertension. CONCLUSION: In this population-based study of older adults, although all measures of blood pressure were strongly and directly related to the risk of coronary and cerebrovascular events, SBP was the best single predictor of cardiovascular events.

Aged↗
PubMed2001

Electrostatic attraction of coupled Wigner crystals: finite temperature effects.

In this paper we present a unified physical picture for the electrostatic attraction between two coupled planar Wigner crystals at finite temperature. This model may facilitate our conceptual understanding of counterion-mediated attractions between (highly) similarly charged planes. By adopting an elastic theory, we show that the total attractive force between them can be (approximately) decomposed into a short-ranged and a long-ranged component. They are evaluated below the melting temperature of the Wigner crystals. In particular, we analyze the temperature dependence of the short-ranged attraction, arising from ground-state configuration, and we argue that thermal fluctuations may drastically reduce its strength. Also, the long-range force agrees exactly with that based on the charge-fluctuation approach. Furthermore, we take quantum contributions to the long-ranged (fluctuation-induced) attraction into account and show how the fractional power law, which scales as d(-7/2) for large interplanar distance d at zero temperature, crosses over to the classical regime d(-3) via an intermediate regime of d(-2).

Journal Article↗
PubMed2001

Potential heating effect in the gravid uterus during MR HASTE imaging.

UNLABELLED: Our purpose was to evaluate if temperature changes occur in maternal or fetal tissues during HASTE imaging. METHODS: Pregnant pigs were scanned with the HASTE technique, and temperatures were measured with phase maps and temperature probes inserted into the amniotic fluid and fetal brain. RESULTS: Fiberoptic probes showed that no heating occurred in fetal tissues or amniotic fluid during HASTE imaging. CONCLUSION: Our current HASTE protocols do not deposit a significant amount of heat in the gravid uterus. J. Magn. Reson. Imaging 2001;13:856-861.

Animals↗
PubMed2001

A review of omeprazole use in the treatment of acid-related disorders in children.

BACKGROUND: Acid peptic disease is a common problem, with a similar prevalence of gastroesophageal reflux disease (GERD) in adults and children. The presentation of GERD in infants and children varies from crying, irritability, or sleep disturbance to feeding difficulties, vomiting, or rumination. Helicobacter pylori (HP)-related diseases and gastric and duodenal ulcers are much more common in adults than in children, who are more likely to have gastritis or duodenitis. However, because HP infection is most likely acquired in childhood, treatment of children with endoscopically documented active HP disease may minimize the potential risk for peptic ulcer or gastric cancer in adulthood, although this is yet to be proved. OBJECTIVE: Omeprazole has been shown to be effective in the treatment of acid-related diseases. This paper reviews the literature on the use and administration of omeprazole for the treatment of GERD, peptic ulcer disease, HP infection, and other acid-related conditions in children. METHODS: Studies were identified through searches of MEDLINE and Science Citation Index for the period 1986 to November 2000, and from the reference lists of identified articles. The search terms used included omeprazole, proton pump inhibitor (PPI), children, pediatrics, routes of administration, GERD, HP infection, esophagitis, and administration. In addition, the manufacturer of omeprazole was asked for relevant unpublished information. RESULTS: Marketed and extemporaneous formulations of omeprazole have been administered to children aged 2 months to 18 years for the treatment of erosive esophagitis, gastric ulcer, duodenal ulcer, HP infection, and related conditions at dosages of 5 to 80 mg/d (0.2-3.5 mg/kg/d) for periods ranging from 14 days to 36 months with a low incidence of adverse effects. The initial dose most consistently reported to heal esophagitis and provide relief of symptoms of GERD appears to be 1 mg/kg per day. CONCLUSIONS: In uncontrolled clinical trials and case reports to date, omeprazole has been effective and well tolerated for the acute and chronic treatment of esophageal and peptic ulcer disease in children, particularly those who had failed to respond to previous treatment with histamine2-receptor antagonists. Should future long-term, controlled clinical trials in children demonstrate safety and efficacy, this PPI is likely to find a place in the armamentarium of pediatric pharmacotherapy.

Administration, Oral↗
PubMed2001

Normal fetal anatomy as visualized with fast magnetic resonance imaging.

The development of ultrafast sequences has revolutionized fetal magnetic imaging (MRI). Fetal anatomy can be characterize precisely by MRI. This is particularly true for evaluation of the central nervous system, for which magnetic resonance (MR) evaluation is superior to ultrasound evaluation. MR allows analysis of development of the cerebrum as well as posterior fossa structures. Awareness of the normal sequence of maturation as well as the approximate timing of development of key structures is useful for evaluating the developing fetus. MRI also permits evaluation of the oropharynx, lungs, diaphragm, and intra-abdominal and retroperitoneal structures. Occasionally, beautiful depiction of smaller structures, including extremities and details of the face and neck may be obtained, but this is dependent on the orientation of the fetus and the plane of imaging as well as the section thickness. MRI is useful in assignment of fetal gender as well as in evaluation of the chorionicity of twin gestations. This report illustrates the normal appearance of the developing fetus as seen on fast sequences during the second and third trimesters.

Embryonic and Fetal Development↗
PubMed2001

Ultrasound versus magnetic resonance imaging in fetal evaluation.

Ultrasound is the screening modality of choice for fetal imaging. However, there are circumstances in which an alternate imaging modality is needed for additional information regarding fetal anatomy or pathology. Fast magnetic resonance imaging (MRI) is increasingly being used as a correlative imaging modality in pregnancy because it uses no ionizing radiation, provides excellent soft-tissue contrast, and has multiple planes for reconstruction and a large field of view. However, sonographic evaluation of the fetus still is important to select the appropriate fetuses for magnetic resonance (MR) examination and to guide the protocol of the examination. Performance of high-quality sonographic and MR examinations as well as interpretation by individuals familiar with prenatal diagnosis are important factors for optimal parental counseling. MRI frequently adds additional information beyond that available with ultrasound. This information commonly changes patient counseling and, at times, patient management.

Female↗
PubMed2001

Fast fetal magnetic resonance imaging techniques.

New hardware and software allow for increased magnetic resonance imaging (MRI) speed. This speed is crucial for MRI of the fetus, where motion degrades image quality. Single-shot sequences such as echo-planar and single-shot fast spin echo now are practical with most clinical scanners. This article reviews and illustrates the physics of fast magnetic resonance sequences.

Echo-Planar Imaging↗
PubMed2001

Magnetic resonance imaging in prenatal diagnosis.

Ultrasound is the screening modality of choice for fetal imaging. However, when additional information regarding fetal anatomy or pathology is needed, fast magnetic resonance (MR) imaging is being used increasingly as a correlative imaging modality because it uses no ionizing radiation, provides excellent soft tissue contrast, has multiple planes for reconstruction, and a large field of view. Sonographic examination of the fetus is still important for selecting the appropriate fetuses for MR examination and to guide the protocol of the examination. Performance of high quality sonographic and MR examinations, as well as interpretation by individuals familiar with prenatal diagnosis, are important factors for optimal parental counseling. Magnetic resonance imaging frequently adds additional information beyond that available with ultrasound. This information commonly changes patient counseling, and at times patient management.

Central Nervous System↗