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Biomedical subjects

P Baker

Publications and source records attributed to P Baker.

At least 37 records · Page 2Linked to original sources
PubMed2001

Inducible change in the behavior of resistance arteries from circulating factor in preeclampsia: an effect specific to myometrial vessels from pregnant women.

OBJECTIVE: It has previously been observed that a circulating factor or factors may be responsible for the changes in vessel behavior that are postulated to underlie the pathogenesis of preeclampsia. We wished to ascertain whether such changes in endothelial function are dependent on the vascular bed under investigation. STUDY DESIGN: Myometrial and infracolic omental vessels resistance vessels were obtained at cesarean delivery or hysterectomy. After incubation with either plasma from women with preeclampsia or plasma from normotensive pregnant women, myographic techniques were used to assess the endothelium-dependent relaxations of these vessels. RESULTS: Incubation of myometrial vessels from normotensive pregnant women with plasma from women with preeclampsia resulted in a significant reduction in endothelium-dependent relaxation, an effect that was independent of the parity of the patients from whom the vessels had been taken. Incubation of omental vessels from normotensive pregnant women and myometrial vessels from nonpregnant women with plasma from women with preeclampsia had no effect on the endothelium-dependent relaxation observed. CONCLUSIONS: This study demonstrates that the inducible changes in resistance vessel behavior are dependent on the tissue bed under investigation and on the pregnancy status of the patient.

Adult↗
PubMed2001

The preliminary characterization of a vasoactive circulating factor(s) in preeclampsia.

OBJECTIVE: The endothelium-dependent behavior of myometrial resistance vessels from women with preeclampsia differs dramatically from that of healthy pregnant women. Similar functional changes may be induced in vessels from healthy pregnant women by incubation with plasma from women with preeclampsia. STUDY DESIGN: Myometrial arterioles, obtained from healthy pregnant women at elective cesarean section, were incubated with plasma from women with preeclampsia or plasma from healthy pregnant women. Myographic techniques were used to study the endothelium-dependent relaxation to bradykinin. The effects of subjecting plasma from women with preeclampsia to heat treatment, charcoal stripping, protein extraction and digestion, and column fractionation on the inducible changes in endothelial function were likewise investigated. RESULTS: Incubation with plasma from women with preeclampsia resulted in a significant reduction in the vessel's endothelium-dependent relaxation, a change that was reversible. This effect was reduced by heat treating and charcoal stripping, maintained within a plasma protein concentrate, and completely removed by protease digestion. The vasoactive component(s) of the plasma had a molecular weight greater than 100 kd. CONCLUSIONS: Plasma of women with preeclampsia alters the endothelium-dependent relaxation of myometrial vessels. Our findings suggest that such alterations are induced by a high-molecular-weight protein/glycoprotein, with possible contributions from a hydrophobic, lipophilic factor.

Adult↗
PubMed2001

A classification of tasks in bioinformatics.

MOTIVATION: This paper reports on a survey of bioinformatics tasks currently undertaken by working biologists. The aim was to find the range of tasks that need to be supported and the components needed to do this in a general query system. This enabled a set of evaluation criteria to be used to assess both the biology and mechanical nature of general query systems. RESULTS: A classification of the biological content of the tasks gathered offers a checklist for those tasks (and their specialisations) that should be offered in a general bioinformatics query system. This semantic analysis was contrasted with a syntactic analysis that revealed the small number of components required to describe all bioinformatics questions. Both the range of biological tasks and syntactic task components can be seen to provide a set of bioinformatics requirements for general query systems. These requirements were used to evaluate two bioinformatics query systems.

Computational Biology↗
PubMed2001

Preparing future aging advocates: the Oklahoma Aging Advocacy Leadership Academy.

PURPOSE: This article describes the organization, operation, and evaluation of the Oklahoma Aging Advocacy Leadership Academy (OAALA). DESIGN AND METHODS: The Academy was designed to assure the continuation of future cohorts of advocates and volunteers for aging programs and services. It is a statewide training program consisting of 10 weekend sessions. The curriculum incorporates age-related content and advocacy/leadership/voluntary skills training. Evaluation consisted of: (a) a pre-post assessment of perceived familiarity with advocacy and volunteer leadership issues; (b) post-Academy participant assessments of the quality of various aspects of the Academy; (c) post-Academy written statements about areas that were valuable and in need of change; and (d) a compilation of student volunteer and advocacy activities. RESULTS: Evaluation results indicate that the OAALA led to significant increases in perceived familiarity with issues and very positive participant assessments of quality. In addition, many participants spontaneously initiated advocacy and volunteer activities while enrolled in the Academy. IMPLICATIONS: Our experience with the Academy suggests that it is a feasible means of preparing individuals to become successful old-age advocates and volunteer leaders.

Adult↗
PubMed2001

Abnormal fetal growth is not associated with altered chorionic villous expression of vascular endothelial growth factor mRNA.

Altered placental and circulating levels of vascular endothelial growth factor (VEGF) and its receptor (flt-1) may be associated with pre-eclampsia and intrauterine growth restriction (IUGR). The aim of this study was to determine whether chorionic villous VEGF or flt-1 mRNA are altered at early gestation in pregnancies subsequently found to be complicated by abnormal fetal growth. Quantitative reverse transcription-polymerase chain reaction was performed on chorionic villous samples for VEGF and flt-1 using an internal RNA standard. Using the individualized birthweight ratio (IBR), the subjects (n = 51) were divided into three groups; IUGR (IBR <10th centile, n = 6), normal (IBR 10th-90th centiles, n = 41) and macrosomic (IBR >90th centile, n = 4). There was no correlation between the mRNA expression of VEGF(121) or VEGF(165) and gestational age of the normal controls. There was also no difference in the expression of either of the VEGF isoforms between the IUGR or macrosomic groups and the normal controls. Expression of flt-1 was below the detection limit of the assay. In conclusion, we have found that altered chorionic villous expression of VEGF is not associated with the initial stages of development of IUGR or macrosomia.

Actins↗
PubMed2001

Genetic predisposition to bleeding during oral anticoagulant therapy: evidence for common founder mutations (FIXVal-10 and FIXThr-10) and an independent CpG hotspot mutation (FIXThr-10).

The recent discovery of five patients with coumarin sensitive FIX-variants due to a missense mutation in the FIX propeptide, either Ala-10Val or Ala-10Thr, has highlighted a novel type of genetic predisposition to bleeding during oral anticoagulant therapy (OAT). In the present study, we report six additional patients with such FIX variants. Haplotype analysis of FIX polymorphisms revealed a founder effect in the five German and Swiss patients with the Val-10 variant. Also, four Thr-10 variants detected in Germany, Switzerland and Great Britain derived from a common founder. Two Thr-10 variants from USA showed an independent de novo origin at a CpG dinucleotide that in general represents a mutation hotspot. These findings implicate the existence of additional subjects with corresponding variants in the populations of various countries. Even though the rare occurrence of these variants does not justify a general aPTT screening during OAT, it is recommended to monitor each bleeding event during OAT in males in order to exclude a genetic predisposition to bleeding by means of the following testing strategy: a) aPTT-testing in each bleeding complication of male patients during OAT, b) if aPTT is disproportionately prolonged, determination of FIX:C, and c) if FIX:C is disproportionately decreased as compared to FII:C, FVII:C and FX:C, sequencing of exon 2 of the FIX gene. This strategy will provide a cost-effective and safe procedure to identify patients that carry the FIX variants. Moreover, such a strategy accumulates data about the prevalence of these FIX mutations in a given population.

Administration, Oral↗
PubMed2000

Racial, age, and rural/urban disparity in cervical cancer incidence.

PURPOSE: High mortality rates of cervical cancer among black women have been observed for several decades in the Southeast. The purpose of this study is to assess the factors associated with this geographic and racial enigma, and to see if incidence is consistent with mortality.METHODS: Using the Savannah River Regional Health Information System (SRRHIS), a 5-year cancer registry from 1991-1995, incidence rates were calculated and compared to rates from Surveillance, Epidemiology, and End Results (SEER). The rates per 100,000/year were analyzed by race, rural/nonrural, and age (<45 and >/=45).Rates are similar between SRRHIS and SEER except in the case of black women over the age of 45. These women in rural SRRHIS have 1.66 times the incidence rate compared to those in nonrural SRRHIS and 1.97 times the rate of rural SEER.RESULTS:Table 1CONCLUSIONS: The results of the study suggest that the incidence of cervical cancer in the region is consistent with the mortality rates. The age-group with the highest rates are black women over 45 in rural areas, suggesting the need to target this group to reduce the racial disparity in cervical cancer.

Journal Article↗
PubMed2000

Spatial patterns in the distribution of tropical tree species.

Fully mapped tree census plots of large area, 25 to 52 hectares, have now been completed at six different sites in tropical forests, including dry deciduous to wet evergreen forest on two continents. One of the main goals of these plots has been to evaluate spatial patterns in tropical tree populations. Here the degree of aggregation in the distribution of 1768 tree species is examined based on the average density of conspecific trees in circular neighborhoods around each tree. When all individuals larger than 1 centimeter in stem diameter were included, nearly every species was more aggregated than a random distribution. Considering only larger trees (>/= 10 centimeters in diameter), the pattern persisted, with most species being more aggregated than random. Rare species were more aggregated than common species. All six forests were very similar in all the particulars of these results.

Central America↗
PubMed2000

An evaluation of an oral health training programme for carers of the elderly in residential homes.

OBJECTIVE: The objectives of this study were: to evaluate carers' knowledge of oral health; to provide a high quality, consistent, oral health training programme for carers in residential homes; to evaluate the quality of this programme by examining both carers' changes in knowledge and any changes in carers' behaviour as reported by residents and to assess any changes in the oral health of the elderly residents after one year. DESIGN: A cross-sectional, multi-centre study using a carer training programme, evaluated by both a questionnaire conducted with carers and residents and oral examination of residents. SETTING: In August 1996, 20 (20%) of the residential/nursing homes, in West Hertfordshire were chosen at random and all managers contacted and offered an oral examination for all their residents. Ten (10%) of the homes were also offered an oral health training programme for their carers. Eighteen homes accepted the oral examination for all consenting residents and 7 of the 10 homes offered accepted the carer training. SUBJECTS: Thirty-nine carers from 7 of the residential homes attended an oral health training course and 213 elderly residents in the 18 homes were examined both at baseline and after 12 months. RESULTS: Carers' baseline knowledge about oral health was poor; the oral health training programme was enjoyed and their knowledge gain after one week was high. However, the elderly residents perceived no change in the oral care given by carers either after one week or after one year and there was no measurable improvement in the oral health of residents after carer training, except for an increase in filled coronal surfaces. Few of the carers originally trained were still working in the same residential homes after one year. CONCLUSION: Although the carer training programme was well received, no changes in oral health practice resulted. Barriers to practice of oral care by carers remained and training, even when including practical skills, evaluation by peers and a high knowledge gain, failed to reduce these barriers.

Aged↗
PubMed2000

Inheritance of avermectin resistance in Haemonchus contortus.

A larval development assay was used to compare the responses of the Chiswick Avermectin Resistant (CAVRS) isolate of Haemonchus contortus, an avermectin-susceptible isolate (VRSG) and their crosses to avermectins. The F(1) and F(2) generations of reciprocal crosses between CAVRS and VRSG were denoted as CAVRS malesxVRSG females=CXV, and VRSG malesxCAVRS females=VXC. The levels of avermectin resistance in the developing larvae of the F(1) of both CXV and VXC were indistinguishable from that in the avermectin-resistant parent, indicating that the resistance trait is completely dominant. Avermectin dose-response curves for the CXV F(1) did not show a 50% mortality rate at low concentrations, indicating that avermectin resistance is not sex-linked. This conclusion was confirmed when adult male worms of the F(1) of the CXV mating were found to have survived treatment of the host with 200microgkg(-1) ivermectin. This dose rate (200microgkg(-1) ivermectin) caused a 50% reduction in the number of adult males in the F(1) from both CXV and VXC crosses, but only a non-significant reduction in the number of adult females in the F(1). Dose-response curves obtained for the F(2) generations in the larval development assay indicated the presence of 25% of avermectin-susceptible individuals, suggesting that a single major gene largely controls the avermectin-resistance trait. This genetic analysis of avermectin resistance in an Australian H. contortus isolate indicates that the expression of the gene for avermectin resistance is an autosomal, complete dominant in the larvae; however, in adults its expression is sex-influenced, with males having a lower resistance to avermectin than females.

Animals↗
PubMed2000

Do physicians judge a study by its cover? An investigation of journal attribution bias.

The effect of a journal's prestige on readers' impressions of an article is unknown. Two hypotheses were tested: first, that attribution of a study to a "high" prestige journal would be associated with improved impressions and attribution to a "low" prestige journal would be associated with diminished impressions; and second, that formal training in epidemiology and biostatistics would mitigate the effects of this journal attribution bias. The study was designed as a trial among a random sample of 264 internists. Participants were asked to read an article and an abstract from either the Southern Medical Journal (SMJ) or the New England Journal of Medicine (NEJM). Questionnaires were constructed that either attributed the article or abstract to its source or presented it as unattributed. After each article or abstract, respondents were asked to rate the quality of the study, the appropriateness of the methodology employed, the significance of the findings, and its likely effects on their practice. A 20-point impression score was created based on responses to these statements. The effect of attribution to a specific journal and formal epidemiology training on impression scores were assessed using linear regression. Of the 399 eligible participants, 264 questionnaires were returned (response rate 66%). Differences in impression scores associated with attribution of an article or abstract to the NEJM were.71 [95% C.I. (-.44-1.87)] and.50 [95% C.I. (-.87-1.87)] respectively; differences in impression scores associated with attribution of an article or abstract to the SMJ were -.12 [95% C.I. (-1.53-1.30)] and -.95 [95% C.I. (-2.41-.52)]. A stratified analysis demonstrated that epidemiology training did not meaningfully alter the effect of journal attribution on participants' impression scores. If journal attribution bias exists, it is likely to exert small and clinically insignificant effects when physicians read articles carefully. Formal training in epidemiology and biostatistics does not appear to alter these results.

Bias↗
PubMed2000

Journal reading habits of internists.

We assessed the reading habits of internists with and without epidemiological training because such information may help guide medical journals as they make changes in how articles are edited and formatted. In a 1998 national self-administered mailed survey of 143 internists with fellowship training in epidemiology and study design and a random sample of 121 internists from the American Medical Association physician master file, we asked about the number of hours spent reading medical journals per week and the percentage of articles for which only the abstract is read. Respondents also were asked which of nine medical journals they subscribe to and read regularly. Of the 399 eligible participants, 264 returned surveys (response rate 66%). Respondents reported spending 4.4 hours per week reading medical journal articles and reported reading only the abstract for 63% of the articles; these findings were similar for internists with and without epidemiology training. Respondents admitted to a reliance on journal editors to provide rigorous and useful information, given the limited time available for critical reading. We conclude that internists, regardless of training in epidemiology, rely heavily on abstracts and prescreening of articles by editors.

Adult↗
PubMed2000

Serological survey and active surveillance for La Crosse virus infections among children in Tennessee.

In 1998 and 1999, we performed a serosurvey and active surveillance for La Crosse encephalitis at a children's hospital in eastern Tennessee. Fifteen cases of La Crosse encephalitis were confirmed. Only 5 (0.5%) of 1000 serum samples being tested at the state laboratory for other diseases had evidence of antibodies to La Crosse virus. These findings suggest that La Crosse virus is newly endemic to eastern Tennessee.

Adolescent↗
PubMed2000

TAMBIS: transparent access to multiple bioinformatics information sources.

UNLABELLED: TAMBIS (Transparent Access to Multiple Bioinformatics Information Sources) is an application that allows biologists to ask rich and complex questions over a range of bioinformatics resources. It is based on a model of the knowledge of the concepts and their relationships in molecular biology and bioinformatics. AVAILABILITY: TAMBIS is available as an applet from http://img.cs.man.ac.uk/tambis SUPPLEMENTARY: A full manual, tutorial and videos can be found at http://img.cs.man.ac.uk/tambis. CONTACT: tambis@cs.man.ac.uk

Computational Biology↗
PubMed2000

Plasma from women with pre-eclampsia induces an in vitro alteration in the endothelium-dependent behaviour of myometrial resistance arteries.

OBJECTIVE: To compare the in vitro effect of plasma from normal pregnant women and women with pre-eclampsia on the endothelium-dependent behaviour of myometrial resistance arteries from normal pregnant women. DESIGN: An in vitro comparative study. SETTING: Nottingham City Hospital. SAMPLE: Uterine biopsy specimens were obtained from normal pregnant women delivered by elective caesarean section at term. Plasma was collected from nulliparous women with pre-eclampsia (n = 18), and from multiparous normal pregnant women (n = 18), all samples being matched for maternal age and gestation at venepuncture. Pools of plasma from women with pre-eclampsia and normal pregnant women were formed from these samples and were used in all the experiments. METHODS: Myometrial resistance vessels obtained from the uterine biopsies were incubated with normal pregnant plasma, plasma from women with pre-eclampsia, or without plasma. Wire myography was employed to study the effect of plasma on the endothelium-dependent behaviour of these vessels. RESULTS: Incubation of vessels from normal pregnant women with plasma from women with pre-eclampsia resulted in a significant reduction in endothelium-dependent relaxation, compared with vessels incubated either with plasma from normal pregnant women or without plasma. This alteration in endothelial function occurred after an incubation period of one hour and required a threshold concentration for its effect to become established. Removal of the vascular endothelium abolished these changes in vessel behaviour. There were no plasma-induced alterations in the endothelium-independent behaviour of the vascular smooth muscle. CONCLUSIONS: This study supports the hypothesis that plasma from women with pre-eclampsia is capable of altering endothelium-dependent myometrial relaxation in vessels from pregnant women.

Adult↗
PubMed1999

Attitudes of carers and the elderly occupants of residential homes to antimicrobial chewing gum as an aid to oral health.

OBJECTIVE: The aim of this study was to investigate the attitudes of elderly residents to using an antimicrobial chewing gum as an aid to oral health, and the opinion of their carers on such a procedure. DESIGN: A cross-sectional, multi-centre survey using a structured interview/questionnaire conducted with elderly residents and their carers. SETTING: In January 1998, 9 residential/nursing homes were chosen at random from all the homes in West Hertfordshire, 207 residents were asked to chew two pieces of gum twice daily for 7 days. SUBJECTS: The participants, 148 women and 59 men, were aged between 53-100 years (mean age 82.23 +/- 9.62 years). 47 carers, all female, were involved in distributing and collecting the gum. RESULTS: 122 residents (58.9%) were edentulous and 85 (41%) of the participants were partially dentate. Of those with teeth 23 (27%) had 21 teeth or more. 73 (35.2%) residents found that chewing the gum was difficult with 37 (17.9%) of this group being unable to chew (P < 0.0001 for those residents with no teeth/dentures or dentures unopposed by teeth or other dentures). 32 (18.6%) subjects disliked the flavour of the gum. Of the 170 residents who chewed the gum 99 (57.2%) found it reduced oral dryness and 78 (45.1%) reported it made their mouth feel healthy. 34 (53.6%) of the dentate and 47 (40.9%) of the edentate residents wished to keep using the gum (P < 0.05). 35 (74.5%) of the carers found it easy to distribute the gum and 29 (61.7%) thought that chewing gum was an acceptable method of maintaining oral health for residents. CONCLUSION: The antimicrobial gum investigated in this study was acceptable to many elderly occupants and their carers, significantly improving perceived oral health and oral dryness of residents.

Aged↗