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William Stewart

Publications and source records attributed to William Stewart.

14 recordsLinked to original sources
PubMed2006

Recommendations for chamber quantification.

Quantification of cardiac chamber size, ventricular mass and function ranks among the most clinically important and most frequently requested tasks of echocardiography. Over the last decades, echocardiographic methods and techniques have improved and expanded dramatically, due to the introduction of higher frequency transducers, harmonic imaging, fully digital machines, left-sided contrast agents, and other technological advancements. Furthermore, echocardiography due to its portability and versatility is now used in emergency rooms, operating rooms, and intensive care units. Standardization of measurements in echocardiography has been inconsistent and less successful, compared to other imaging techniques and consequently, echocardiographic measurements are sometimes perceived as less reliable. Therefore, the American Society of Echocardiography, working together with the European Association of Echocardiography, a branch of the European Society of Cardiology, has critically reviewed the literature and updated the recommendations for quantifying cardiac chambers using echocardiography. This document reviews the technical aspects on how to perform quantitative chamber measurements of morphology and function, which is a component of every complete echocardiographic examination.

Cardiac Volume↗
PubMed2006

Cortical neurogenesis enhanced by chronic perinatal hypoxia.

Most regions of the mature mammalian brain, including the cerebral cortex, appear to be unable to support the genesis of new neurons. Here, we report that a low level of neurogenesis occurs in the cerebral cortex of the infant mouse brain and is enhanced by chronic perinatal hypoxia. When mice were reared in a low-oxygen environment from postnatal days 3 to 11, approximately 30% of the cortical neurons were lost after the insult; yet this damage was transient. The loss of cortical neuron number, cortical volume, and brain weight were all reversed during the recovery period. At P18, 7 days after the cessation of hypoxia, there was a marked increase in astroglial cell proliferation within the SVZ, as assessed by 5-bromodeoxyuridine (BrdU) incorporation in S-phase cells. One month after BrdU incorporation, 40% more BrdU-positive cells were found in the cerebral cortex of hypoxic-reared as compared to normoxic control mice. Among these newly generated cortical cells, approximately 45% were oligodendrocytes, 35% were astrocytes, and 10% were neurons in both hypoxic and normoxic mice. However, twice as many BrdU-labeled cells expressed neuronal markers in the neocortex in mice recovering from hypoxia as compared to controls. In both hypoxic-reared and normoxic infant/juvenile mice, putative neuroblasts could be seen detaching from the forebrain subventricular zone, migrating through the subcortical white matter and entering the lower cortical layers, 5 to 11 days after their last mitotic division. We suggest that cortical neurogenesis may play a significant role in repairing neuronal losses after neonatal injury.

Age Factors↗
PubMed2004

A descriptive analysis of an integrative medicine clinic.

OBJECTIVE: To evaluate and describe an integrative medicine clinic including its patients; their presenting problems, medical objectives, treatment recommendations; whether recommendations were recalled and adhered to; and patients' self-reported health outcomes. DESIGN: A prospective cohort study of 160 new clinic patients were treated using a wide range of integrative medicine therapies. Patients were interviewed at intervals of 1, 3, and 6 months after their initial visit. SETTING: The study was conducted at the Institute for Health and Healing clinic, at California Pacific Medical Center located in San Francisco, CA. SUBJECTS: The subjects were new clinic patients seeking care for a variety of symptoms and diagnoses. INTERVENTION: Patients presented with an average of 4.0 symptoms and 2.9 diagnoses; physicians recommended 9.5 "treatments" per patient. RESULTS: At 6-month follow-up, symptom intensity decreased from 6.5 to 4.2 (on a 10-point scale; p < 0.005); and 57% of the patients had made "substantial" progress or had completely achieved their health objectives (p < 0.005). The Short Form 12 (SF-12) measure of mental and physical functioning improved significantly from baseline to one month (p = 0.05; p = 0.001, respectively) and maintained this improvement at 3 (p = 0.01; p = 0.01) and 6 months (p = 0.001; p = .001). At 1-month follow-up, patients recalled 57% of the actionable statements from the physician without a prompt and they followed 55% of all recommendations well (90% or above). Over the follow-up period, patients increasingly attributed the reductions in symptoms (p = 0.01) and achieving their health objectives (p = 0.01) to the treatment plan. Self-reported measures of days ill and days missed at work/school did not differ significantly from the year before coming to the clinic. CONCLUSION: The results indicate that patients can recall and follow a complex treatment regimen. Subjective and objective measures of patients' health status improved after one month and this effect was sustained or improved further at 6 months follow-up. Further study is needed to determine whether patients' improvement was the result of the treatment regimen.

Adolescent↗
PubMed2003

Approaches to mapping genetically correlated complex traits.

Our Markov chain Monte Carlo (MCMC) methods were used in linkage analyses of the Framingham Heart Study data using all available pedigrees. Our goal was to detect and map loci associated with covariate-adjusted traits log triglyceride (lnTG) and high-density lipoprotein cholesterol (HDL) using multipoint LOD score analysis, Bayesian oligogenic linkage analysis and identity-by-descent (IBD) scoring methods. Each method used all marker data for all markers on a chromosome. Bayesian linkage analysis detected a linkage signal on chromosome 7 for lnTG and HDL, corroborating previously published results. However, these results were not replicated in a classical linkage analysis of the data or by using IBD scoring methods.We conclude that Bayesian linkage analysis provides a powerful paradigm for mapping trait loci but interpretation of the Bayesian linkage signals is subjective. In the absence of a LOD score method accommodating genetically complex traits and linkage heterogeneity, validation of these signals remains elusive.

Cholesterol, HDL↗
PubMed2003

A1 adenosine receptors mediate hypoxia-induced ventriculomegaly.

Periventricular leukomalacia is characterized by a reduction in brain matter and secondary ventriculomegaly and is a major cause of developmental delay and cerebral palsy in prematurely born infants. Currently, our understanding of the pathogenesis of this condition is limited. In animal models, features of periventricular leukomalacia can be induced by hypoxia and activation of A1 adenosine receptors (A1ARs). Using mice that are deficient in the A1AR gene (A1AR-/-), we show that A1ARs play a prominent role in the development of hypoxia-induced ventriculomegaly in neonates. Supporting a role for adenosine in the pathogenesis of developmental brain injury, ventriculomegaly was also observed in mice lacking the enzyme adenosine deaminase, which degrades adenosine. Thus, adenosine acting on A1ARs appears to mediate hypoxia-induced brain injury ventriculomegaly during early postnatal development.

Animals↗
PubMed2003

Boater preferences for beach characteristics downstream from Glen Canyon Dam, Arizona.

Release flow decisions are increasingly being influenced by an array of social values, including those related to river-based recreation. A substantial portion of past recreation research on downstream impacts of dams has focused on variability of instream flows. This study complements past research by assessing user preferences for beach characteristics affected by long-term impacts of flow regimes. Based upon a study of three recreational user groups (private trip leaders, commercial passengers, and river guides) of the Colorado River in Grand Canyon, preferences for beach size, presence of shade on beach, and presence of vegetation on beach are examined. Results indicate that large size beaches with shade from trees are setting characteristics with highly reliable and strong user preferences. The multinomial regression models developed for each user group indicate that 80% of all respondents would choose beach campsites 800 m(2); results were the same regardless of respondents' past boating experience, boat type (i.e. oar or motorized), or group size. In addition, size of beach was consistently reported to be a trip feature of moderate importance to respondents' river trip. Implications of this research are related to future prospects for controlled floods (i.e. spike flows) released from Glen Canyon Dam.

Arizona↗
PubMed2003

An integrative medicine clinic in a community hospital.

We report on the creation of an integrative medicine clinic within the setting of a medical research and tertiary care hospital. The clinical audit used a prospective case series of 160 new patients who were followed by telephone interviews over a 6-month period. Patients' demographic characteristics, presenting symptoms and diagnoses, physician treatment recommendations, extent of understanding and adherence to treatment recommendations, changes in symptom intensity, and progress toward achieving health objectives were recorded. Patients at the clinic showed significant reductions in the severity of symptoms and made significant progress toward achieving their health objectives at the 6-month follow-up. Thus far, the clinic's experience suggests that an integrative medicine clinic can face current health care financial challenges and thrive in a conventional medical center.

Complementary Therapies↗
PubMed2002

Unexpected retention and concomitant loss of subtelomeric regions in balanced chromosome anomalies by FISH.

Florescence in situ hybridization (FISH) using subtelomeric probes has been useful in detecting cryptic telomeric chromosomal rearrangements. We report, for the first time, that cytogenetically visible chromosome rearrangements can occur between the subtelomeric and telomeric region in clinically normal individuals with balanced chromosome anomalies in which one of the breakpoints involves a terminal band region. Using FISH with subtelomeric probes, we observed in three cases with a balanced reciprocal translocations the retention and subsequent loss of subtelomeric regions. In one case with a paracentric inversion, there was a proximal relocation of a subtelomeric region. Because subtelomeric regions serve important roles in chromosome pairing, this retention and concomitant loss or relocation of a subtelomeric region could possibly further disrupt the complex meiotic configurations of these balanced chromosome rearrangements. This may then have an effect on gamete production, placing these individuals at a higher risk for miscarriages and/or abnormal outcomes for individuals with similar chromosome aberrations.

Abortion, Habitual↗
PubMed2002

Blood concentrations of cyclosporin a during long-term treatment with cyclosporin a ophthalmic emulsions in patients with moderate to severe dry eye disease.

To quantify blood cyclosporin A (CsA) concentrations during treatment with CsA topical ophthalmic emulsions, blood was collected from 128 patients enrolled in a Phase 3, multicenter, double-masked, randomized, parallel-group study of CsA eyedrops for treatment of moderate to severe dry eye disease. Patients received 0.05% CsA, 0.1% CsA, or vehicle b.i.d. for 6 months; vehicle-treated patients then crossed over to 0.1% CsA b.i.d. for 6 months. CsA concentrations were measured using a validated LC/MS-MS assay (quantitation limit = 0.1 ng/mL). No patient receiving 0.05% CsA had any quantifiable CsA in the blood (n = 96 samples). All but 7 of 128 (5.5%) trough blood samples from the 0.1% CsA group were below the quantitation limit for CsA; none exceeded 0.3 ng/mL. CsA was also below the limit of quantitation in 205 of 208 (98.6%) of serial postdose blood samples collected from 26 patients during 1 dosing interval between months 9 and 12. The highest C(max) measured, 0.105 ng/mL at 3 hours postdose, occurred in a 0.1% CsA-treated patient. These results indicate that long-term use of topical CsA ophthalmic emulsions at doses that are clinically efficacious for treating dry eye will not cause any system-wide effects.

Adult↗