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L Barker

Publications and source records attributed to L Barker.

At least 19 recordsLinked to original sources
PubMed2006

Longitudinal farm study of extended-spectrum beta-lactamase-mediated resistance.

Extended-spectrum beta-lactamase (ESBL)-mediated resistance is of considerable importance in human medicine. Recently, such enzymes have been reported in bacteria from animals. We describe a longitudinal study of a dairy farm suffering calf scour with high mortality rates. In November 2004, two Escherichia coli isolates with resistance to a wide range of beta-lactams (including amoxicillin-clavulanate and cefotaxime) were isolated from scouring calves. Testing by PCR and sequence analysis confirmed the isolates as being both bla(CTX-M14/17) and bla(TEM-35) ((IRT-4)) positive. They had indistinguishable plasmid and pulsed-field gel electrophoresis (PFGE) profiles. Transferability studies demonstrated that bla(CTX-M) was located on a conjugative 65-MDa IncK plasmid. Following a farm visit in December 2004, 31/48 calves and 2/60 cows were positive for E. coli with bla(CTX-M). Also, 5/48 calf and 28/60 cow samples yielded bla(CTX)- and bla(TEM)-negative E. coli isolates that were resistant to cefotaxime, and sequence analysis confirmed that these presented mutations in the promoter region of the chromosomal ampC gene. Fingerprinting showed 11 different PFGE types (seven in bla(CTX-M)-positive isolates). Six different PFGE clones conjugated the same bla(CTX-M)-positive IncK plasmid. One clone carried a different-sized, bla(CTX-M)-positive, transformable plasmid. This is the first report of bla(CTX-M) from livestock in the United Kingdom, and this report demonstrates the complexity of ESBL epidemiology. Results indicate that horizontal plasmid transfer between strains as well as horizontal gene transfer between plasmids have contributed to the spread of resistance. We have also shown that some clones can persist for months, suggesting that clonal spread also contributes to the perpetuation of resistance.

Animals↗
PubMed2006

The National Violent Death Reporting System: an exciting new tool for public health surveillance.

The US does not have a unified system for surveillance of violent deaths. This report describes the National Violent Death Reporting System (NVDRS), a system for collecting data on all violent deaths (homicides, suicides, accidental firearms deaths, deaths of undetermined intent, and deaths from legal intervention, excluding legal executions) in participating states. The NVDRS centralizes data from many sources, providing a more comprehensive picture of violent deaths than would otherwise be available. The NVDRS collects data on victims, suspects, and circumstances related to the violent deaths. Currently, 17 US states participate in the NVDRS; the intention is for the NVDRS to become a truly national system, representing all 50 states, the District of Columbia, and the US territories. This report describes the history of the NVDRS, provides an overview of how the NVDRS functions, and describes future directions.

Centers for Disease Control and Prevention, U.S.↗
PubMed2006

Homicide of children aged 0-4 years, 2003-04: results from the National Violent Death Reporting System.

INTRODUCTION: To better understand, and ultimately prevent, infant/child homicide, it is imperative to more thoroughly elucidate the circumstances and conditions related to such instances. Data were obtained from the US National Violent Death Reporting System (NVDRS) to illuminate circumstances related to homicide among children aged 4 years or less, and to identify demographic groups which may be at increased risk. METHODS: The NVDRS is an active surveillance system that provides comprehensive information on all violent deaths that occur within participating states within the US. Standard statistical tests were conducted to determine homicide rates among children ages 0-4 across states that provided data for both 2003 and 2004 (Alaska, Maryland, Massachusetts, New Jersey, Oregon, South Carolina, and Virginia). These data were further used to investigate infant/child homicides by race, gender, and other relevant circumstances (for example, victim-suspect relationship, weapon type, and location of homicide). A Poisson regression model was fitted to the sample data to investigate the multivariate relationship between the infant/child homicide rate and available demographic information. RESULTS: The 2003 homicide rate for children ages 0-4 was 3.0 per 100,000 population. The 2004 homicide rate was 2.5 per 100,000 population. African Americans were 4.2 times as likely as whites to be victims of homicide. Suspects were commonly parents/caregivers. The vast majority of infant/child homicides occurred in houses or apartments, using weapons that include household objects. CONCLUSION: Homicides of infants and young children are most often committed in the home, by parents/caregivers, using "weapons of opportunity". This suggests that the risk of infant/child homicide is greatest within the primary care giving environment. Moreover, the use of "weapons of opportunity" may be indicative of maladaptive stress responses. Prevention and intervention strategies to reduce infant/child homicide should target the home environment and attend to maladaptive stress responses.

Black or African American↗
PubMed2006

Characteristics of homicide followed by suicide incidents in multiple states, 2003-04.

OBJECTIVE: To calculate the prevalence of homicide followed by suicide (homicide/suicide) and provide contextual information on the incidents and demographic information about the individuals involved using data from a surveillance system that is uniquely equipped to study homicide/suicide. METHODS: Data are from the National Violent Death Reporting System (NVDRS). This active state-based surveillance system includes data from seven states for 2003 and 13 states for 2004. The incident-level structure facilitates identification of homicide/suicide incidents. RESULTS: Within participating states, 65 homicide/suicide incidents (homicide rate = 0.230/100,000) occurred in 2003 and 144 incidents (homicide rate = 0.238/100,000) occurred in 2004. Most victims (58%) were a current or former intimate partner of the perpetrator. Among all male perpetrators of intimate partner homicide 30.6% were also suicides. A substantial proportion of the victims (13.7%) were the children of the perpetrator. Overall, most victims (74.6%) were female and most perpetrators were male (91.9%). A recent history of legal problems (25.3%), or financial problems (9.3%) was common among the perpetrators. CONCLUSIONS: The results support earlier research documenting the importance of intimate partner violence (IPV) and situational stressors on homicide/suicide. These results suggest that efforts to provide assistance to families in crisis and enhance the safety of IPV victims are needed to reduce risk for homicide/suicide. The consistency of the results from the NVDRS with those from past studies and the comprehensive information available in the NVDRS highlight the promise of this system for studying homicide/suicide incidents and for evaluating the impact of prevention policies and programs.

Adolescent↗
PubMed2006

Race/ethnicity, substance abuse, and mental illness among suicide victims in 13 US states: 2004 data from the National Violent Death Reporting System.

OBJECTIVE: To calculate the prevalence of substance abuse and mental illness among suicide victims of different racial/ethnic groups and to identify race/ethnicity trends in mental health and substance abuse that may be used to improve suicide prevention. METHODS: Data are from the National Violent Death Reporting System (NVDRS), a state-based data integration system that, for 2004, includes data from 13 US states. The NVDRS integrates medical examiner, toxicology, death certificate, and law enforcement data. RESULTS: Within participating states, for data year 2004, 6865 suicide incidents in which race/ethnicity are known were identified. This included 5797 (84.4%) non-Hispanic whites, 501 (7.3%) non-Hispanic blacks, 257 (3.7%) Hispanics, and 310 (4.5%) persons from other racial/ethnic groups. At the time of the suicide event, non-Hispanic blacks had lower blood alcohol contents than other groups. Non-Hispanic whites had less cocaine but more antidepressants and opiates. There were no differences in the levels of amphetamines or marijuana by race/ethnicity. Hispanics were less likely to have been diagnosed with a mental illness or to have received treatment, although family reports of depression were comparable to non-Hispanic whites and other racial/ethnic groups. Non-Hispanic whites were more likely to be diagnosed with depression or bipolar disorder and non-Hispanic blacks with schizophrenia. Comorbid substance abuse and mental health problems were more likely among non-Hispanic whites and non-Hispanic blacks, while Hispanics were more likely to have a substance abuse problem without comorbid mental health problems. CONCLUSION: The results support earlier research documenting differences in race/ethnicity, substance abuse, and mental health problems as they relate to completed suicide. The data suggest that suicide prevention efforts must address not only substance abuse and mental health problems in general, but the unique personal, family, and social characteristics of different racial/ethnic groups.

Adolescent↗
PubMed2002

Prognosis in post-infective irritable bowel syndrome: a six year follow up study.

BACKGROUND: Irritable bowel syndrome developing following infective gastroenteritis accounts for approximately 1 in 10 of unselected IBS patients. AIMS: To define the long term natural history of post-infective IBS (PI-IBS). METHODS: A total of 436 individuals, who had previously responded to a questionnaire on their bowel habits following an acute episode of gastroenteritis, were sent a questionnaire about their current bowel habits and physical and mental health six years after their initial illness. RESULTS: Complete data on original bowel habit, episodes of gastroenteritis, mental health history, and subsequent bowel habit at six years were obtained in 192 individuals. Of these, there were 14 cases of "post-infective IBS" (PI-IBS) and 13 who had IBS prior to infection (previous IBS). Over the six year follow up period there were 20 "new non-infective IBS cases" (new IBS). The strongest risk factor for developing any type of IBS was female sex (relative risk 2.2, p<0.05). Compared with new IBS, those with PI-IBS had significantly more days with loose stools (p<0.05) but a similar number of days with pain, urgency, and bloating. Six of 14 (43%) PI-IBS and four of 13 (31%) previous IBS patients recovered by six years (NS). Of 27 IBS patients followed for six years, only 1/8 with a history of anxiety or depression recovered compared with 9/19 without such a history (p=0.19). CONCLUSION: PI-IBS differs from non-infective IBS by having more diarrhoeal features. Less than half of both PI-IBS and non-infective IBS cases recover over six years. A history of anxiety and depression severe enough to warrant treatment may impair recovery but larger numbers are needed to prove this.

Adult↗
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↗