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Biomedical subjects

R Wilson

Publications and source records attributed to R Wilson.

At least 73 records · Page 4Linked to original sources
PubMed2001

Primary ciliary dyskinesia syndrome associated with abnormal ciliary orientation in infants.

Primary ciliary dyskinesia (PCD) syndrome associated with abnormal ciliary orientation but with normal ciliary ultrastructure has been described in adults, but there are no normal ranges for orientation in infants, despite the fact that half of all patients with PCD present in the new-born period. Nasal brush biopsies were obtained from eight infants (three males), mean age 13.1 months, range 7-23, in order to determine ciliary orientation. They had no upper or lower airway disease and normal organ arrangement and were undergoing general anaesthesia for other reasons. Two infants with typical PCD syndrome but normal ultrastructure of individual cilia also had orientation studies. In the eight normal subjects, a mean of 254 central pairs was examined, range 82-453. The mean ciliary orientation was 14.9 degrees, range 12.9-17.5. The two infants with PCD syndrome but normal ultrastructure of individual cilia had ciliary orientation of (Case 1) 44.5 degrees (range 10.6-64.5) in 218 central pairs; and on a second occasion, 28.9 degrees, (range 9.0-47.5) in 259 central pairs; for Case 2, 24.4 degrees, (range 13.1-38.4) in 196 central pairs. The normal range for ciliary orientation is similar in infants to that described in other work in adults. The two cases of phenotypic primary ciliary dyskinesia in the presence of normal ciliary ultrastructure but abnormal ciliary orientation in infants supports the contention that measurement of ciliary orientation should be part of the assessment of ciliary structure and function in cases of possible primary ciliary dyskinesia, in particular when the ultrastructure of individual cilia appear to be normal.

Cilia↗
PubMed2001

Bacteria, antibiotics and COPD.

Bacterial infection is one of several important causes of exacerbations of chronic obstructive pulmonary disease (COPD) that may coexist. COPD is a heterogeneous condition and the incidence of bacterial infection is not uniform; mucus hypersecretion may be an important risk factor. The bacteriology of infections varies depending on the severity of the underlying airway disease. There is now a much better understanding of the pathogenesis of bacterial infections of the respiratory mucosa. Lower airway bacterial colonization may be a stimulus for chronic inflammation and may influence the interval between exacerbations. Antibiotic resistance has increased in all the major pathogens. Antibiotics are an important part of the treatment of acute exacerbations of COPD and the decision about whether to give an antibiotic can be made on clinical grounds. It is more difficult to decide, on the available evidence, whether patient characteristics and the risk of antibiotic resistance should influence choice of empiric antibiotic treatment. Most new antibiotics are modifications of existing structures, suggesting that every effort should be made to conserve the sensitivity of current antibiotics by using them appropriately.

Drug Resistance↗
PubMed2001

Age distribution of cancer in mice: the incidence turnover at old age.

We have studied cancer incidence in mice as a function of age in those cohorts where the rodents are allowed to live very close to their full natural lifetime. We find that the incidence rises as a function of age, but then flattens and turns over at an age of about 800 days. This behaviour is similar to that which we observed (Pompei and Wilson, 2001) in the Surveillance, Epidemiology, and End Results (SEER) data where the age distribution of human cancer incidence turns over at about age 80. Although other fits are possible, the three-parameter beta function model fits both the mouse data and the human data well. The beta model implies, and the data do not deny, the interpretation that cancer is not a certainty and mice may also outlive their cancers, although high-dose cohort results suggest cancer might be certain if dose is sufficiently high. Limited data suggest that the cancer age distribution, including the turnover, may be time shifted by dietary restriction.

Age Distribution↗
PubMed2001

Opioids for chronic nonmalignant pain. Attitudes and practices of primary care physicians in the UCSF/Stanford Collaborative Research Network. University of California, San Francisco.

BACKGROUND: We hoped to determine the attitudes and practices of primary care physicians regarding the use of opioids to treat chronic nonmalignant pain (CNMP). We also examined the factors associated with the willingness to prescribe opioids for CNMP. METHODS: A survey was mailed to primary care physicians in the University of California, San Francisco/Stanford Collaborative Research Network. This survey contained questions regarding treatment in response to 3 case vignettes, the use of opioids for CNMP in general, and the demographic characteristics of the physicians. RESULTS: Among 230 physicians surveyed, 161 (70%) responded. Two percent of the respondents were never willing to prescribe schedule III opioids (eg, acetaminophen with codeine) as needed for patients with CNMP that persisted unchanged after exhaustive evaluation and attempts at treatment. Thirty-five percent were never willing to prescribe schedule II opioids (eg, sustained-release morphine) on an around-the-clock schedule for these patients. The most significant predictor of willingness to prescribe opioids for patients with CNMP was a lower level of concern about physical dependence, tolerance, and addiction. CONCLUSIONS: Primary care physicians are willing to prescribe schedule III opioids as needed, but many are unwilling to use schedule II opioids around the clock for CNMP. Individual prescribing practices vary widely among primary care physicians. Concerns about physical dependence, tolerance, and addiction are barriers to the prescription of opioids by primary care physicians for patients with CNMP.

Adolescent↗
PubMed2000

Measurements of the mass, total width, and two-photon partial width of the eta(c) meson.

Using 13.4 fb(-1) of data collected with the CLEO detector at the Cornell Electron Storage Ring, we have observed 300 events for the two-photon production of ground-state pseudoscalar charmonium in the decay eta(c)-->K(0)(S)K-/+pi(+/-). We have measured the eta(c) mass to be [2980.4+/-2.3 (stat)+/-0.6 (syst)] MeV and its full width as [27.0+/-5.8 (stat)+/-1.4 (syst)] MeV. We have determined the two-photon partial width of the eta(c) meson to be [7.6+/-0.8 (stat)+/-0.4 (syst)+/-2.3 (br)] keV, with the last uncertainty associated with the decay branching fraction.

Journal Article↗
PubMed2000

Ceramide-coated balloon catheters limit neointimal hyperplasia after stretch injury in carotid arteries.

Neointimal hyperplasia at the site of surgical intervention is a common and deleterious complication of surgery for cardiovascular diseases. We hypothesized that direct delivery of a cell-permeable growth-arresting lipid via the balloon tip of an embolectomy catheter would limit neointimal hyperplasia after stretch injury. We have previously demonstrated that sphingolipid-derived ceramide arrested the growth of smooth muscle cell pericytes in vitro. Here, we show that ceramide-coated balloon catheters significantly reduced neointimal hyperplasia induced by balloon angioplasty in rabbit carotid arteries in vivo. This ceramide treatment decreased the number of vascular smooth muscle cells entering the cell cycle without inducing apoptosis. In situ autoradiographic studies demonstrated that inflating the balloon catheter forced cell-permeable ceramide into the intimal and medial layers of the artery. Intercalation of ceramide into vascular smooth muscle cells correlated with rapid inhibition of trauma-associated phosphorylation of extracellular signal-regulated kinase and protein kinase B. These studies demonstrate the utility of cell-permeable ceramide as a novel therapy for reducing neointimal hyperplasia after balloon angioplasty.

Angioplasty, Balloon, Coronary↗
PubMed2000

Fibroblast growth factor receptor-dependent morphogenesis of the Drosophila mesoderm.

The Drosophila fibroblast growth factor (FGF) receptors Heartless and Breathless are required for the morphogenesis of the mesoderm and the tracheal system. In this article we discuss a number of questions relating to the morphogenesis of these tissues and speculate on poorly understood aspects of the underlying mechanisms. As yet a ligand has not been identified for Heartless, but in the case of Breathless the ligand may in some situations act as a chemotactic signal. We consider it unlikely that release of a distant chemotactic signal plays a role in the morphogenesis of the mesoderm. Instead we propose that the change in the mesoderm from an invaginated epithelium to a single layer of cells spread out on the ectoderm could be a result of the mesodermal cells trying to maximize their contact with the ectoderm. Exactly how the activation of the FGF receptors affects cell behaviour and leads to cell movement is not understood. The signal could simply be permissive, causing cells to become motile, or it could act as a directional signal for cells that are already motile, or perhaps provide both functions. Furthermore, it is unclear how signal transduction is coupled to morphological change. It seems unlikely that activation of transcription targets is essential for cell migration and it is possible that FGF signalling may have a direct effect on the cytoskeleton independent of the activation of the mitogen-activated protein kinase cascade. Analysis of the function of dof, which encodes a cytoplasmic protein required for FGF signal transduction may provide an insight into these issues.

Animals↗
PubMed2000

Fringe is a glycosyltransferase that modifies Notch.

Notch receptors function in highly conserved intercellular signalling pathways that direct cell-fate decisions, proliferation and apoptosis in metazoans. Fringe proteins can positively and negatively modulate the ability of Notch ligands to activate the Notch receptor. Here we establish the biochemical mechanism of Fringe action. Drosophila and mammalian Fringe proteins possess a fucose-specific beta1,3 N-acetylglucosaminyltransferase activity that initiates elongation of O-linked fucose residues attached to epidermal growth factor-like sequence repeats of Notch. We obtained biological evidence that Fringe-dependent elongation of O-linked fucose on Notch modulates Notch signalling by using co-culture assays in mammalian cells and by expression of an enzymatically inactive Fringe mutant in Drosophila. The post-translational modification of Notch by Fringe represents a striking example of modulation of a signalling event by differential receptor glycosylation and identifies a mechanism that is likely to be relevant to other signalling pathways.

Animals↗
PubMed2000

Study of exclusive radiative B meson decays

We have studied exclusive, radiative B meson decays to charmless mesons in 9.7x10(6) B&Bmacr; decays accumulated with the CLEO detector. We measure B(B0-->K(*0)(892)gamma) = (4.55(+0.72)(-0. 68)+/-0.34)x10(-5) and B(B+-->K(*+)(892)gamma) = (3.76(+0.89)(-0. 83)+/-0.28)x10(-5). We have searched for CP asymmetry in B-->K(*)(892)gamma decays and measure A(CP) = +0.08+/-0.13+/-0.03. We report the first observation of B-->K(*)(2)(1430)gamma decays with a branching fraction of (1.66(+0.59)(-0.53)+/-0.13)x10(-5). No evidence for the decays B-->rhogamma and B0-->omegagamma is found and we limit B(B-->(rho/omega)gamma)/B(B-->K(*)(892)gamma)<0.32 at 90% C.L.

Journal Article↗
PubMed2000

Effects of hospitalists on cost, outcomes, and patient satisfaction in a rural health system.

PURPOSE: Previous studies have examined the effects of hospitalists in urban academic hospitals. We compared the outcomes of patients treated by hospitalists with those of patients treated by internists at a 647-bed rural community hospital. SUBJECTS AND METHODS: The 443 patients in the hospitalists' 10 most common diagnosis-related groups (DRGs) were compared with 1,681 patients in the same DRGs who were cared for by internists in fiscal year 1998. Length of stay, cost of care, patient illness severity, patient satisfaction, 30-day readmission rate, inpatient mortality, discharge status, and resource utilization were compared. RESULTS: The hospitalists' patients had a shorter mean (+/- SD) length of stay (4.1 +/- 3.0 days versus 5.5 +/- 4.9 days, P <0.001) and their cost of care was less than that of the internists' patients ($4,098 +/- $2,455 versus $4,658 +/- $4,084, P <0.001). Analyses that adjusted for patient age, race, sex, insurance status, severity of illness, and specific medical comorbidities confirmed these differences. The differences between hospitalists and internists were most apparent among very ill patients. Mortality rates were similar (4.5% for hospitalists versus 4.9% for internists, P = 0.80), as were the readmission rates (4.5% for hospitalists versus 5.6% for internists, P = 0.41). Patient satisfaction was similar for both groups. The internists used more resources in 8 of 11 categories. CONCLUSIONS: The hospitalists provided cost-effective care, particularly for the sickest patients, with good outcomes and patient satisfaction.

Health Resources↗
PubMed2000

Effect of lysozyme on the lectin-mediated phagocytosis of Bacillus cereus by haemocytes of the cockroach, Blaberus discoidalis.

Lysozyme-like activity has been demonstrated in both cell-free haemolymph and, more abundantly, in haemocyte-lysate supernatants of Blaberus discoidalis. This activity was non-inducible, but heat-stable, with a maximum activity at pH 6.2. When B. cereus was pre-incubated in a concentration of chicken egg-white lysozyme equivalent to the concentration of lysozyme-like activity in cell-free haemolymph, the phagocytosis of B. cereus opsonized with GlcNAc-specific lectins, i.e. BDL2, WGA and HPA, was significantly reduced by up to 50%, while phagocytosis of B. cereus opsonized with mannose-specific lectins, such as BDL1 and Con A, was significantly increased. Pre-incubation of B. cereus in a higher concentration of lysozyme resulted in a smaller, shorter lived increase in the phagocytic rate of bacteria opsonized with these mannose-specific lectins. The action of lysozyme on the peptidoglycan in the cell wall of B. cereus probably resulted in a reduction in the number of binding sites for the GlcNAc-specific lectins, and, therefore, reduced the phagocytic rate of BDL2, HPA and WGA-opsonized B. cereus. Concomitantly, the breakdown of peptidoglycan probably exposed mannose-containing polysaccharides, previously embedded in the peptidoglycan layer, resulting in an increase in the phagocytic rate of the BDL1- and Con A-opsonized B. cereus. These results are discussed in relation to the immune-potential of B. discoidalis.

Journal Article↗
PubMed2000

Laser modulation of angiogenic factor production by T-lymphocytes.

BACKGROUND AND OBJECTIVE: In previous investigations, small variations in the energy densities of low level light therapy (LLLT) were found to produce significant differences in the proliferation of resting T-lymphocytes in vitro. Pulsing these cells with mitogen in addition to laser therapy produced inhibitory effects regardless of the amplitude of the energy density used. In the current study, the effect of LLLT on the production of angiogenic factor(s) by T-lymphocytes was investigated in vitro. STUDY DESIGN/MATERIALS AND METHODS: Human T-cells isolated from peripheral blood were prepared in suspension either with or without addition of mitogen. Cell suspensions were irradiated with laser by using the following energy densities: 1.2, 3.6, 6.0, and 8.4 J/cm(2). Wavelength, pulsing frequency, and power output were kept constant at 820 nm, 5,000 Hz, and 50 mW, respectively. After either 3 or 5 days of incubation, lymphocyte supernatants were collected and added as conditioned media to cultured endothelial cells (ECs). The effect on the proliferation of these ECs was assessed over a 72-hour period by using a methylene blue assay. RESULTS: Endothelial cell proliferation increased significantly when incubated with conditioned media collected from resting T-cells exposed to 1.2 and 3.6 J/cm(2). Day 5 conditioned media produced similar patterns of EC proliferation to that of day 3 but at lower magnitude. Pulsing of T-lymphocytes with mitogen in addition to laser irradiation significantly lessened their angiogenic capability. Conditioned media from 3.6 J/cm(2) laser-treated T-cells induced the maximal EC proliferation in all groups studied. CONCLUSION: It would seem that laser therapy stimulates lymphocytes to produce factor(s) that can modulate EC proliferation in vitro; this effect on the lymphocytes is influenced by (1) the amplitude of energy density used for T-cell irradiation, (2) exposing T-cells to both mitogen and laser, and (3) the duration of T-cell incubation in culture.

Angiogenesis Inducing Agents↗