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R Wilson

Publications and source records attributed to R Wilson.

At least 91 records · Page 5Linked to original sources
PubMed2001

Evidence of New States Decaying into Xi(*)(c)pi.

Using 13.7 fb(-1) of data recorded by the CLEO detector at Cornell Electron Storage Ring, we report evidence of two new charmed baryons: one decaying into Xi(0')(c)pi(+) with the subsequent decay Xi(0')(c)-->Xi(0)(c)gamma, and its isospin partner decaying into Xi(+')(c)pi(-) followed by Xi(+')(c)-->Xi(+)(c)gamma. We measure the following mass differences for the two states: M(Xi(0)(c)gammapi(+))-M(Xi(0)(c)) = 318.2+/-1.3+/-2.9 MeV and M(Xi(+)(c)gammapi(-))-M(Xi(+)(c)) = 324.0+/-1.3+/-3.0 MeV. We interpret these new states as the J(P) = 1 / 2(-) Xi(c1) particles, the charmed-strange analogs of the Lambda(+)(c1)(2593).

Journal Article↗
PubMed2001

Observation of B --> phiK and B --> phiK*.

We have studied two-body charmless hadronic decays of B mesons into the final states straight phiK and phiK(*). Using 9.7 million B&Bmacr; pairs collected with the CLEO II detector, we observe the decays B- --> phiK- and B0--> phiK(*0) with the following branching fractions: B(B--->phiK-) = (5.5(+2.1)(-1.8)+/-0.6)x10(-6) and B(B0--> phiK(*0)) = (11.5(+4.5+1.8)(-3.7-1.7))x10(-6). We also see evidence for the decays B0-->phiK0 and B---> phiK(*-). However, since the statistical significance is not overwhelming for these modes, we determine upper limits of <12.3x10(-6) and <22.5x10(-6) ( 90% confidence level), respectively.

Journal Article↗
PubMed2001

Measurement of the relative branching fraction of upsilon(4S) to charged and neutral B-meson pairs.

We analyze 9.7x10(6) B_B pairs recorded with the CLEO detector to determine the production ratio of charged to neutral B-meson pairs produced at the Upsilon(4S) resonance. We measure the rates for B0-->J/psiK((*)0) and B+-->J/psiK((*)+) decays and use the world-average B-meson lifetime ratio to extract the relative widths f(+-) / f(00) = gamma(Upsilon(4S)-->B+B-) / gamma(Upsilon(4S)-->B0 B-0)) = 1.04+/-0.07(stat)+/-0.04(syst). With the assumption that f(+-)+f(00) = 1, we obtain f(00) = 0.49+/-0.02(stat)+/-0.01(syst) and f(+-) = 0.51+/-0.02(stat)+/-0.01(syst). This production ratio and its uncertainty apply to all exclusive B-meson branching fractions measured at the Upsilon(4S) resonance.

Journal Article↗
PubMed2001

Measurement of the lambda(+)(c) lifetime.

The Lambda+c lifetime is measured using 9.0 fb(-1) of e+e- annihilation data collected on or just below the Upsilon(4S) resonance with the CLEO II.V detector at CESR. Using an unbinned maximum likelihood fit, the Lambda+c lifetime is measured to be 179.6+/-6.9(stat)+/-4.4(syst) fs. The precision of this colliding beam measurement is comparable to other measurements, which are based on fixed-target experiments, with different systematic uncertainties.

Journal Article↗
PubMed2001

Electrochemiluminescence determination of 2',6'-difluorophenyl 10-methylacridan-9-carboxylate.

Electrochemical oxidation of the acridan 2',6'-difluorophenyl 10-methylacridan-9-carboxylate produces the corresponding acridinium ester, which reacts with hydrogen peroxide forming a dioxetanone intermediate. Decomposition of the dioxetanone generates light at 430 nm when it relaxes to the ground state. The effect of pH and hydrogen peroxide concentration on this ECL reaction and on the stability of the acridan were investigated. At pH 8.0 and a hydrogen peroxide concentration of 10 mM, light emission from the ECL reaction was used to determine the acridan concentration with a detection limit of 54 pmol L(-1). Results suggest that acridan esters could be used as labels in ECL immunoassays and nucleotide assays.

Acridines↗
PubMed2001

A physical map of human chromosome 14.

We report the construction of a tiling path of around 650 clones covering more than 99% of human chromosome 14. Clone overlap information to assemble the map was derived by comparing fully sequenced clones with a database of clone end sequences (sequence tag connector strategy). We selected homogeneously distributed seed points using an auxiliary high-resolution radiation hybrid map comprising 1,895 distinct positions. The high long-range continuity and low redundancy of the tiling path indicates that the sequence tag connector approach compares favourably with alternative mapping strategies.

Chromosomes, Artificial, Bacterial↗
PubMed2001

Genomewide survey of panic disorder.

We completed a genome scan of 23 multiplex families of panic disorder. Ninety family members had DSM-III-R panic disorder, and another 23 had recurrent, spontaneous panic attacks that did not satisfy these criteria. We typed 469 markers from the CHLC map (ver 8c7) with an average intermarker distance of 10.3 cM. Two-point lod scores were calculated with both a dominant and a recessive model, and maps of lod scores < -2.00, assuming genetic homogeneity, were constructed by using DSM-III-R panic disorder as the affected phenotype. Lod scores were < -2.00 over 94-95% of the genome. The greatest lod score was 2.23 (theta = 0.15) at the D7S2846 locus, located at 57.8 cM on chromosome 7 according to the Marshfield Clinic map. Flanking markers analyzed in a nonparametric, multipoint analysis using GENEHUNTER resulted in an NPL score of 2.97 at 63 cM on the Marshfield map. This region lies within 15 cM from the D7S435 locus, where Knowles et al. [1998] obtained a lod score of 1.71 (theta = 0.10) for panic disorder (now 2.45 with the addition of new families; James Knowles, personal communication). Thus, the maximum evidence of linkage from two genome scans of panic disorder lies within a small region of chromosome 7p.

Adult↗
PubMed2001

Chain separation of monounsaturated fatty acid methyl esters by argentation thin-layer chromatography.

A technique for separating methyl esters of monounsaturated fatty acids by argentation chromatography using silver nitrate-impregnated TLC plates is described. Monounsaturated fatty acid methyl esters are separated from polyunsaturated and saturated fatty acid methyl esters and the monounsaturated fatty methyl esters are resolved according to chain length. cis isomers are well resolved from the corresponding trans isomers. R(F) values for individual monounsaturated fatty acids are very reproducible. The potential of the technique in metabolic studies is demonstrated in the chain elongation of [14C]-18:1(n-9) and delta-9 desaturation of [14C]-18:0 by human skin fibroblasts. Recoveries of individual [14C]-fatty acids for scintillation counting exceed 94%.

Chromatography, Gas↗
PubMed2001

The role of multimedia interactive programs in training for laparoscopic procedures.

BACKGROUND: The application of minimally invasive techniques to the performance of abdominal surgery by general surgeons has been perhaps the greatest advance in the history of general surgery. The safe adoption of many of these procedures, however, has been hampered by significant obstacles, mainly due to the problem of providing adequate training for surgeons. Outside of animal and cadaver labs, most training has been didactic in nature, and adoption rates after completion of these courses are discouraging. Multimedia interactive training has been used in a number of high-tech industries with great success. A >60% improvement in the learning curve after multimedia interactive training, as compared to traditional didactic training, has been reported. Multimedia interactive training programs for surgeons that use content and input from multiple experts in laparoscopic procedures have now been developed. METHODS: Residents from a general surgery residency program who used these programs were asked to rate their effectiveness in increasing their knowledge and comfort level prior to their participation in a real procedure as the primary surgeon or first assistant. A comparison to other traditional training techniques was also made. Eleven residents completed 41 programs designed to teach one of five different laparoscopic procedures-cholecystectomy, fundoplication, appendectomy, colon resection, or hernia repair. RESULTS: On a scale of 1 to 10, with 10 being the highest, the residents reported that the multimedia interactive training programs raised their knowledge level of the procedure from 6.0 to 8.7 (+2.7 point value increase after using the multimedia interactive program). The programs increased their comfort level when actually called on to perform or assist with the procedure from 5.3 to 8.1 (+2.8 point value increase after using the multimedia interactive program). In comparing the value of training methods for learning laparoscopic procedures, the residents rated text, lectures, videos, and animal labs at 4.7, 5.1, 6.0 and 7.3, respectively. By comparison, the residents rated the multimedia interactive training program at 8.8. CONCLUSION: The use of multimedia interactive training programs in addition to current laparoscopic training courses may help to increase the safe adoption of laparoscopic procedures. These programs may be a beneficial adjunct to residency training programs.

Adult↗
PubMed2001

Laparoscopic inguinal hernia repair: lessons learned after 1224 consecutive cases.

BACKGROUND: Despite numerous attempts to improve the techniques used for hernia repair, current published series show that recurrence rates are as high as 5-20%. The complexity of inguinal anatomy, combined with multiple potential areas of weakness, has contributed to the difficulty in preventing recurrences. However, the laparoscopic approach to inguinal herniorrhaphy has allowed clear visualization of all preperitoneal fascial planes and anatomic landmarks, as well as the hernia defect(s) and the peritoneal reflection. In the course of our performance of a series of 1,224 laparoscopic inguinal hernia repairs, we have developed a total extraperitoneal approach that yields excellent results with a low initial recurrence rate. Herein we describe our experience. METHODS: After our initial 300 transabdominal preperitoneal (TAPP) hernia repairs, which resulted in six recurrences, two bowel injuries, one bladder injury, and six cutaneous nerve injuries, the total extraperitoneal approach (TEP) was adopted. RESULTS: The first 300 TEP repairs resulted in one recurrence, two bowel injuries, one bladder injury, and two cutaneous nerve injuries. All major complications occurred in patients who had had previous lower abdominal surgery. In the last 624 TEP herniorrhaphies we implemented some modifications to the technique, especially for patients with previous lower abdominal surgery. In this group we recorded one bladder injury, no cutaneous nerve injuries, and one recurrence. CONCLUSIONS: The total extraperitoneal approach for laparoscopic herniorrhaphy allows for a safe and effective repair with low rates of complication and recurrence. A thorough knowledge of the anatomy of the extraperitoneal space and especially the two- and three-dimensional inguinal anatomy of this space contributed greatly to the evolution of our technique.

Adolescent↗
PubMed2001

Abnormal immunoglobulin subclass patterns in women with a history of recurrent miscarriage.

OBJECTIVE: To determine whether IgG subclass patterns differed between nonpregnant women, healthy pregnant women, and pregnant women with a history of recurrent miscarriage. DESIGN: Controlled clinical study. SETTING: An academic setting. PATIENT(S): Group 1 was comprised of 10 nonpregnant women, group 2 of 10 healthy pregnant women, group 3 of eight pregnant women with a history of recurrent miscarriage and whose pregnancies on this occasion went to term, and group 4 of 10 women with a history of recurrent miscarriage whose pregnancies again failed later in the first trimester. INTERVENTION(S): None of the patients received any medication. MAIN OUTCOME MEASURE(S): Serum levels of total IgG and IgG 1, 2, 3, and 4. RESULT(S): The results obtained showed that normal pregnancy was associated with a significant increase in total IgG production and an increase in IgG subclasses 1, 2, and 3. Women with a history of miscarriage, but who had a successful pregnancy on this occasion, showed a similar pattern of IgG subclasses. Women with a history of miscarriage and whose pregnancy again ended in miscarriage showed a different IgG subclass pattern. CONCLUSION(S): Pregnancies that ended in miscarriage showed a different pattern of IgG subclasses than those that continued to term. The changes seen in immunoglobulin patterns could be linked to changes in cytokine production.

Abortion, Habitual↗
PubMed2001

Hepatitis B vaccines: assessment of the seroprotective efficacy of two recombinant DNA vaccines.

BACKGROUND: In universal vaccination programs, when there is no postvaccination sero-1 logic assessment of response, there must be confidence that the vaccines used provide a high degree of seroprotection. OBJECTIVE: This parallel analysis of 2 recombinant hepatitis B vaccines (Engerix B and Recombivax/HB-Vax II) was conducted to review the seroprotective efficacy of each vaccine in defined populations. METHODS: Clinical studies of the 2 vaccines published as manuscripts or conference abstracts in the public domain between January 1986 and April 1999 were identified retrospectively by unrestricted screening of journals through BIOSIS, MEDLINE, and EMBASE and the Internet. Unpublished or internal company data were excluded to maintain impartiality. The studies were reviewed and analyzed. The studies were not assessed for quality other than a judgment of their eligibility for inclusion in the analysis. The primary outcome measure was the proportion of subjects in defined populations who showed an early seroprotective response to currently licensed vaccination schedules. Summary statistical analyses of seroprotective response rates and 95% CIs were calculated for each vaccine for each population. Seroprotective response was defined by an anti-hepatitis B surface antigen titer > or =10 IU/L measured between 1 and 3 months after the final vaccination. Because the study was designed specifically to review published immunogenicity data, safety data were not assessed. The study was not designed to demonstrate superiority of one vaccine over the other. RESULTS: A total of 181 clinical studies representing 32,904 vaccinated subjects were reviewed and analyzed, of whom 24,277 had been vaccinated with Engerix B and 8627 vaccinated with Recombivax/ HB-Vax II. Seroprotection was achieved in 20,060 subjects (95.8%) with Engerix B and in 7774 subjects (94.3%) with Recombivax/HB-Vax II in the normal population vaccinated according to currently licensed 3-dose schedules. In a subgroup analysis, response rates in health care workers were 6492 subjects (94.5%) for Engerix B and 3245 subjects (92.2%) for Recombivax/HB-Vax II. Children and adolescents (1-19 years) showed the highest response rates to vaccination (4612 [98.6%], Engerix B; 2292 [98.9%], Recombivax/HB-Vax II). A total of 2875 infants (<1 year) (95.8%) achieved seroprotection with Engerix B; 701 (88.5%) achieved seroprotection with Recombivax/ HB-Vax II. CONCLUSIONS: Hepatitis B vaccination programs using either Engerix B or Recombivax/HB-Vax II can achieve high seroprotective response rates, particularly in childhood and adolescence. Ideally, younger populations should be a primary target in current universal vaccination programs.

Adolescent↗
PubMed2001

The clinical and microbiological effects of a novel acidified sodium chlorite mouthrinse on oral bacterial mucosal infections.

Acidified sodium chlorite mouthrinses have been shown to have equivalent anti-plaque activity to those containing chlorhexidine, the current 'gold standard'. In this study, sodium chlorite mouthrinses (ASC) acidified with either malic or gluconic acids were compared to each other and with a chlorhexidine rinse and sterile water for their effect on salivary bacterial counts. Sixteen subjects participated in the study, which had a cross-over Latin square design. In a second study, a sodium chlorite/gluconic acid rinse was compared with chlorhexidine for its clinical and microbiological effects in 36 patients with oral mucosal infections. The sodium chlorite rinses acidified with malic and gluconic acids and the chlorhexidine rinse caused significant reductions in salivary bacterial counts up to 7 h after a single rinse compared with water. There were no significant differences between the three active treatments. In the mucosal infection study, there was a significant reduction in erythema in the chlorhexidine group compared with the ASC group. Patients who received the ASC rinse reported significantly less discomfort following treatment than those receiving the chlorhexidine rinse. Staphylococcus aureus counts were significantly reduced in the group who received the sodium chlorite rinse. There were no other significant differences between the treatments. ASC appears to be an effective alternative to chlorhexidine mouthrinse.

Adult↗
PubMed2001

Bottlenecks, drift and differentiation: the population structure and demographic history of sika deer (Cervus nippon) in the Japanese archipelago.

We assessed genetic differentiation and diversity in 14 populations of sika deer (Cervus nippon) from Japan and four populations of sika deer introduced to the UK, using nine microsatellite loci. We observed extreme levels of differentiation and significant differences in diversity between populations. Our results do not support morphological subspecies designations, but are consistent with previous mitochondrial DNA analyses which suggest the existence of two genetically distinct lineages of sika deer in Japan. The source of sika introduced to the UK was identified as Kyushu. The underlying structure of Japanese populations probably derives from drift in separate glacial refugia and male dispersal limited by distance. This structure has been perturbed by bottlenecks and habitat fragmentation, resulting from human activity from the mid-nineteenth century. Most current genetic differentiation and differences in diversity among populations probably result from recent drift. Coalescent model analysis suggests sika on each of the main Japanese islands have experienced different recent population histories. Hokkaido, which has large areas of continuous habitat, has maintained high levels of gene flow. In Honshu the population is highly fragmented and is likely to have been evolving by drift alone. In Kyushu there has been a balance between gene flow and drift but all the populations have experienced high levels of drift. Habitat fragment size was not significantly associated with genetic diversity in populations but there was a significant correlation between habitat fragment size and effective population size.

Alleles↗
PubMed2001

The filamentous type III secretion translocon of enteropathogenic Escherichia coli.

Enteropathogenic Escherichia coli (EPEC) uses a type III secretion system (TTSS) to inject effector proteins into the plasma membrane and cytosol of infected cells. To translocate proteins, EPEC, like Salmonella and Shigella, is believed to assemble a macromolecular complex (type III secreton) that spans both bacterial membranes and has a short needle-like projection. However, there is a special interest in studying the EPEC TTSS owing to the fact that one of the secreted proteins, EspA, is assembled into a unique filamentous structure also required for protein translocation. In this report we present electron micrographs of EspA filaments which reveal a regular segmented substructure. Recently we have shown that deletion of the putative structural needle protein, EscF, abolished protein secretion and formation of EspA filaments. Moreover, we demonstrated that EspA can bind directly to EscF, suggesting that EspA filaments are physically linked to the EPEC needle complex. In this paper we provide direct evidence for the association between an EPEC bacterial membrane needle complex and EspA filaments, defining a new class of filamentous TTSS.

Bacterial Proteins↗
PubMed2001

End-stage renal disease: factors affecting referral decisions by family physicians in Canada, the United States, and Britain.

The objective of this study is to determine how patient age, sex, creatinine level, and comorbidity affect referral decisions for the treatment of end-stage renal disease (ESRD) and whether these decisions are affected by physician characteristics in three countries: Canada, the United States, and Britain. A vignette-based questionnaire was mailed to a random sample of family physicians in Ontario, Canada (1,818 physicians); all family physicians in the state of New York (1,814 physicians); and a sample of general practitioners from the south of England (2,228 physicians) in 1996. Physicians were presented with clinical scenarios involving a patient with varying degrees of renal insufficiency and a complicating comorbidity, including angina, diabetes, cancer, mental illness, or socioeconomic circumstances. They were asked to indicate the likelihood of referral. Half the physicians received a questionnaire describing a male patient, and half, a female patient. Mean creatinine levels at which physicians would refer were 260 micromol/L for British physicians, 297 micromol/L for Canadian physicians, and 340 micromol/L for American physicians. No difference in referral rates was found based on the sex of the patient or physician. Sixty-five percent of American and Canadian physicians would refer regardless of patient age, but only 49% of British physicians would do so. Family physicians in the United States, Canada, and Britain function as gatekeepers for patients with ESRD. They are less likely to refer based on increasing severity of comorbid conditions. They also discriminate based on age, but not sex.

Adult↗
PubMed2001

Accuracy of predictions of survival at admission to the intensive care unit.

PURPOSE: The purpose of this study was to compare the accuracy of outcome predictions made on the day of intensive care unit (ICU) admission by critical care physicians, critical care fellows, and primary team physicians. PATIENTS AND METHODS: Fifty-nine consecutive patients admitted to a Medical-Surgical ICU were included in the study. Two ICU attending physicians and two critical care fellows, not involved in medical management, evaluated each new ICU patient at admission and after 48 to 72 hours. Altogether six ICU attendings and six fellows were involved in the study. Each investigator separately assigned probability to each patient of being discharged alive from the ICU and the hospital. On the day of admission the primary service was also asked to estimate the likelihood of successful outcome. All values are expressed in percentiles. Statistical analysis was performed by a logistic regression procedure with a binary outcome. Data are presented as mean +/- SD. RESULTS: Fifty-nine patients were surveyed. Twenty-six (44%) patients died in the ICU, 3 (5%) died in the hospital wards, and 30 (51%) were discharged alive from the hospital. ICU attendings most reliably and accurately estimated patient outcome on admission compared with critical care fellows and primary team physicians. ICU attendings were more consistent than ICU fellows at predicting outcome at 48 and 72 hours. Clinical predictions were better for patients at the extremes of disease severity, and the accuracy of predictions in these patients was highest. Accuracy was diminished in patients with moderate compromise of clinical status. CONCLUSION: ICU attendings predicted most accurately and consistently the final outcome of patients, and ICU fellows estimated outcome more reliably than the primary service. For the most part, the primary service tended to overestimate the probability of favorable outcome of patients for whom ICU admission had been requested. Additionally, clinical accuracy of survival or mortality was best for those patients at the extremes of clinical compromise: this point seems to confirm the validity of using clinical judgement as a guide to restricting ICU resources for those severely compromised or mildly compromised.This study also indicates that predictions of outcome in critically ill patients made within days of admission are statistically valid but not sufficiently reliable to justify irrevocable clinical decisions at present.

Cancer Care Facilities↗