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Biomedical subjects

L Barker

Publications and source records attributed to L Barker.

At least 19 recordsLinked to original sources
PubMed2001

Rotavirus vaccine and intussusception: how much risk will parents in the United States accept to obtain vaccine benefits?

Postlicensure surveillance of a newly licensed rotavirus vaccine suggested an increased risk of intussusception. Little was known about the amount of risk parents would tolerate to obtain the vaccine's benefits or the extent to which risk would reduce the price parents would pay for the vaccine. Parents of infants aged 12 months or younger were asked to accept or reject two hypothetical vaccines associated with varying degrees of risk. Parents chose from a list the amount they would pay for two additional hypothetical vaccines, with and without a risk of intussuception. The authors conducted face-to-face surveys in September 1999 among a convenience sample of parents in three US cities. Of 405 eligible parents, 260 (64%) participated. To achieve a 90% acceptance rate, the vaccine could be associated with no more than 1,794 (95% confidence interval: 1,551, 2,025) cases of intussusception in a fully vaccinated, national cohort of infants. The median willingness to pay for three vaccine doses, when vaccination was associated with 1,400 cases of intussusception, was $36 (95% confidence interval: $28, $46) compared with $110 (95% confidence interval: $96, $126) for the risk-free vaccine. The most important aspect of this study may be the methodology to assess how parents balance the benefits and risks of childhood vaccines.

Adult↗
PubMed2001

Economic analysis of a child vaccination project among Asian Americans in Philadelphia, Pa.

OBJECTIVE: To ascertain the cost-effectiveness and the benefit-cost ratios of a community-based hepatitis B vaccination catch-up project for Asian American children conducted in Philadelphia, Pa, from October 1, 1994, to February 11, 1996. DESIGN: Program evaluation. SETTING: South and southwest districts of Philadelphia. PARTICIPANTS: A total of 4384 Asian American children. INTERVENTIONS: Staff in the community-based organizations (1) educated parents about the hepatitis B vaccination, (2) enrolled physicians in the Vaccines for Children program, and (3) visited homes of children due for a vaccine dose. Staff in the Philadelphia Department of Public Health developed a computerized database; sent reminder letters for children due for a vaccine dose; and offered vaccinations in public clinics, health fairs, and homes. MAIN OUTCOME MEASURES: The numbers of children having received 1, 2, or 3 doses of vaccine before and after the interventions; costs incurred by the Philadelphia Department of Public Health and the community-based organizations for design, education, and outreach activities; the cost of the vaccination; cost-effectiveness ratios for intermediate outcomes (ie, per child, per dose, per immunoequivalent patient, and per completed series); discounted cost per discounted year of life saved; and the benefit-cost ratio of the project. RESULTS: For the completed series of 3 doses, coverage increased by 12 percentage points at a total cost of $268 660 for design, education, outreach, and vaccination. Costs per child, per dose, and per completed series were $64, $119, and $537, respectively. The discounted cost per discounted year of life saved was $11 525, and 106 years of life were saved through this intervention. The benefit-cost ratio was 4.44:1. CONCLUSION: Although the increase in coverage was modest, the intervention proved cost-effective and cost-beneficial.

Adolescent↗
PubMed2000

Extraimmunization among US children.

CONTEXT: Little is known about the extent of extraimmunization, ie, vaccine doses given in excess of the recommended schedule, and whether it should be a public health concern. OBJECTIVES: To determine the extent and cost of extraimmunization in children and to identify its associated factors. DESIGN, SETTING, AND PARTICIPANTS: United States 1997 National Immunization Survey, in which telephone interviews were conducted with parents of 32742 19- to 35-month-old children and vaccination histories were collected from health care providers for 22806 of these children (overall response rate, 68.5%). Estimates were weighted to represent the full sample. MAIN OUTCOME MEASURES: Frequency of extraimmunization compared by vaccine type as well as with adequate immunization; factors associated with extraimmunization; and vaccine and visit costs associated with extraimmunization. RESULTS: Frequency of extraimmunization was less than 5% for each vaccine considered except poliovirus (14.1%). Overall, 21% of children were extraimmunized for at least 1 vaccine vs 31% underimmunized for at least 1 vaccine. In a multivariate model, the strongest contributors to extraimmunization were having more than 1 immunization provider (odds ratio [OR], 2.8; 95% confidence interval [CI], 2.4-3.2) and having multiple types of providers (eg, private and public health department; OR, 2.0; 95% CI, 1.6-2.4). Children seen only in public health department clinics were significantly less likely to be extraimmunized (OR, 0.3; 95% CI, 0.2-0.3). Annual costs associated with extraimmunization for this cohort of children were estimated conservatively at $26.5 million. CONCLUSIONS: These data indicate that extraimmunization can be costly. The challenge is to reduce extraimmunization without interfering with more important efforts to combat underimmunization. Improvements in immunization record keeping and sharing practices may help reduce extraimmunization.

Child, Preschool↗
PubMed2000

SUT2, a putative sucrose sensor in sieve elements.

In leaves, sucrose uptake kinetics involve high- and low-affinity components. A family of low- and high-affinity sucrose transporters (SUT) was identified. SUT1 serves as a high-affinity transporter essential for phloem loading and long-distance transport in solanaceous species. SUT4 is a low-affinity transporter with an expression pattern overlapping that of SUT1. Both SUT1 and SUT4 localize to enucleate sieve elements of tomato. New sucrose transporter-like proteins, named SUT2, from tomato and Arabidopsis contain extended cytoplasmic domains, thus structurally resembling the yeast sugar sensors SNF3 and RGT2. Features common to these sensors are low codon bias, environment of the start codon, low expression, and lack of detectable transport activity. In contrast to LeSUT1, which is induced during the sink-to-source transition of leaves, SUT2 is more highly expressed in sink than in source leaves and is inducible by sucrose. LeSUT2 protein colocalizes with the low- and high-affinity sucrose transporters in sieve elements of tomato petioles, indicating that multiple SUT mRNAs or proteins travel from companion cells to enucleate sieve elements. The SUT2 gene maps on chromosome V of potato and is linked to a major quantitative trait locus for tuber starch content and yield. Thus, the putative sugar sensor identified colocalizes with two other sucrose transporters, differs from them in kinetic properties, and potentially regulates the relative activity of low- and high-affinity sucrose transport into sieve elements.

Amino Acid Sequence↗
PubMed2000

A new subfamily of sucrose transporters, SUT4, with low affinity/high capacity localized in enucleate sieve elements of plants.

A new subfamily of sucrose transporters from Arabidopsis (AtSUT4), tomato (LeSUT4), and potato (StSUT4) was isolated, demonstrating only 47% similarity to the previously characterized SUT1. SUT4 from two plant species conferred sucrose uptake activity when expressed in yeast. The K(m) for sucrose uptake by AtSUT4 of 11.6 +/- 0.6 mM was approximately 10-fold greater than for all other plant sucrose transporters characterized to date. An ortholog from potato had similar kinetic properties. Thus, SUT4 corresponds to the low-affinity/high-capacity saturable component of sucrose uptake found in leaves. In contrast to SUT1, SUT4 is expressed predominantly in minor veins in source leaves, where high-capacity sucrose transport is needed for phloem loading. In potato and tomato, SUT4 was immunolocalized specifically to enucleate sieve elements, indicating that like SUT1, macromolecular trafficking is required to transport the mRNA or the protein from companion cells through plasmodesmata into the sieve elements.

Amino Acid Sequence↗
PubMed2000

Effective leadership within hospice and specialist palliative care units.

UNLABELLED: In this study the Repertory Grid interview technique was used to investigate constructs of leadership held by a group of male and female senior managers from within hospice and Specialist Palliative Care Units (SPCUs) in the UK. The themes that emerged were compared with those from existing research models of leadership. RESULTS: Men and women in these roles describe different constructs of effective leadership. The women's constructs that emerged were predominantly transformational, whilst the men's were predominantly transactional. Themes were also identified in this study, which differed from previous studied, i.e. those of political and environment awareness and the valuing of others' views regardless of their status. These themes do not feature highly in other research, and may be in response to the environment within which hospice and specialist palliative care functions.

Administrative Personnel↗
PubMed2000

Predicting the success of a trial of labor with a simple scoring system.

OBJECTIVE: To determine the applicability of a simple scoring system, by Troyer and Parisi, in predicting the success of a trial of labor among parturients with prior cesarean delivery. STUDY DESIGN: Retrospectively, all patients who underwent a trial of labor over six consecutive years were reviewed. chi 2, Fisher's exact test and analysis of variance followed by the Turkey or Dunn test were used when appropriate. P < .05 was considered significant. RESULTS: There were 263 trials of labor, of which 63% (167) ended in vaginal delivery. While 21% had a score of 0, 40%, 28% and 11% had a score of 1, 2 and at least 3, respectively. The frequency of vaginal birth was significantly different between the four groups (P < .001): 98% for a score of 0, 69% for 1, 40% for 2 and 33% for 3-4. Occurrence of cesarean delivery for cephalopelvic disproportion (2%, 24%, 39%, 56%; P < .001) or for a nonreassuring fetal heart rate tracing (0%, 7%, 21%, 11%; P < .001) was significantly different between the four groups. CONCLUSION: In our population, we confirmed the inverse relationship between the Troyer-Parisi scoring system and a successful trial of labor.

Adult↗
PubMed1999

Identification of a pollen-specific sucrose transporter-like protein NtSUT3 from tobacco.

Pollen cells are symplasmically isolated during maturation and germination. Pollen therefore needs to take up nutrients via membrane carriers. Physiological measurements on pollen indicate sucrose transport in the pollen tube. A cDNA encoding a pollen-specific sucrose transporter-like protein NtSUT3 was isolated from a tobacco pollen cDNA library. NtSUT3 expression is detected only in pollen and is restricted to late pollen development, pollen germination and pollen tube growth. Altogether these data indicate that pollen is supplied not only with glucose, but also with sucrose through a specific sucrose transporter. The respective contribution of each transport pathway may change during pollen tube growth.

Amino Acid Sequence↗
PubMed1994

Pulmonary function in spinal muscular atrophy.

We present the first prospective study on pulmonary function in spinal muscular atrophy patients. Seventy-seven spinal muscular atrophy patients, ages 5 to 18 years, from three centers, were studied with regard to forced vital capacity, using height as a predictor. Patients were categorized into four motor function categories. The highest-functioning group had normal or near-normal values, and those who sat with support had the lowest values. Those with intermediate function had intermediate values. Forced vital capacity was studied longitudinally in 40 spinal muscular atrophy patients for 1.1 to 4.4 years. Eighty-eight percent of patients grew in height, but only 35% showed an increase in height-adjusted forced vital capacity percent. In those patients with the least function, 100% lost height-adjusted forced vital capacity over time. In those patients with the highest function, 57% lost height-adjusted forced vital capacity. In addition, the basic forced vital capacity, not correlated to height, decreased in 43% of cases. These pulmonary function alterations appear to be important determinants for function and survival in spinal muscular atrophy patients.

Adolescent↗
PubMed1993

The Australian Incident Monitoring Study. The pulse oximeter: applications and limitations--an analysis of 2000 incident reports.

The first 2000 incidents reported to the Australian Incident Monitoring Study were analysed with respect to the role of the pulse oximeter. Of these 184 (9%) were first detected by a pulse oximeter and there were a further 177 (9%) in which desaturation was recorded. Of the 1256 incidents which occurred in association with general anaesthesia 48% were "human detected" and 52% "monitor detected". The pulse oximeter was ranked first and detected 27% of these monitor detected incidents; this figure would have been over 40% if an oximeter had always been used and its more informative modulated pulse tone relied upon instead of that of the "bleep" of the ECG. The pulse oximeter is the "front-line" monitor for endobronchial intubation, the fourth most common incident in association with general anaesthesia (it detected 87% of the 76 cases in which it was in use). It also played an invaluable role as a "back-up" monitor in 40 life-threatening situations in which "front-line" monitors (e.g. oxygen analyser, low pressure alarm, capnograph) were either not in use, were being used incorrectly or failed. Other situations detected, in order of frequency of detection, were: circuit disconnection, circuit leak, desaturation (severe shunt), oesophageal intubation, aspiration and/or regurgitation, pulmonary oedema, endotracheal tube obstruction, severe hypotension, failure of oxygen delivery, hypoxic gas mixture, hypoventilation, anaphylaxis, air embolism, bronchospasm, malignant hyperthermia, and tension pneumothorax.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidents↗
PubMed1993

The Australian Incident Monitoring Study. The oxygen analyser: applications and limitations--an analysis of 200 incident reports.

The first 2000 incidents reported to the Australian INcident Monitoring Study were analysed with respect to the role of the oxygen analyser; 27 (1%) were first detected by the oxygen analyser. All of these were amongst the 1256 incidents which occurred in association with general anaesthesia, of which 48% were "human detected" and 52% "monitor detected". The oxygen analyser was ranked 7th and detected 4% of these monitor detected incidents. This figure would have been much higher had the oxygen analyser been correctly used on more occasions. The oxygen analyser detected 10 ventilator-driving-gas leaks into the circuit, 6 hypoxic mixtures due to rotameter settings, 3 inappropriate nitrous oxide concentrations, 2 disconnections and 1 leak at the common gas outlet, and 2 partial and 1 total failure of ventilation. In a theoretical analysis of these 1256 incidents it was considered that the oxygen analyser, used on its own, would have detected 114 (9%), had they been allowed to evolve (3% before any potential for organ damage). In 4 incidents an oxygen analyser gave faulty readings, in 3 caused a leak and in one a total circuit obstruction; 5 incidents were not detected because the alarm had been disabled. Despite the advent of piped gas supplies, failure of gas delivery or delivery of a "wrong" gas mixture still occurs surprisingly frequently in current anaesthetic practice; hypoxic mixtures were supplied on 16 occasions, other "wrong" mixtures on 23 and the oxygen supply failed on 7 occasions.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidents↗