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Biomedical subjects

K Pearce

Publications and source records attributed to K Pearce.

At least 19 recordsLinked to original sources
PubMed2003

Echis time, under-carboxylated prothrombin and vitamin K status in intensive care patients.

Vitamin K deficiency is a known cause of coagulopathy in hospitalized patients, but the extent of the problem has not been well assessed. This noninterventional, prospective observational study of 35 adults was undertaken in the intensive care unit (ICU) and examined the incidence of and the methods for diagnosing vitamin K deficiency. Measurements of prothrombin time, Echis time and plasma concentrations of under-carboxylated prothrombin (proteins induced in vitamin K absence or antagonism, PIVKA-II), vitamin K1 and ferritin were made during the 48 h after admission to the unit and repeated if coagulopathy developed later. Plasma vitamin K1 was low in 15 admissions (43%), in 11 cases of patients with coagulopathy and in four cases without coagulopathy. PIVKA-II was present in 12 cases (34%), of whom four had low vitamin K1 levels. All of the eight patients with raised PIVKA-II but normal vitamin K concentration were hyperferritinaemic. We conclude that low plasma vitamin K levels, suggestive of low tissue stores, are common in intensive care patients with or without coagulopathy. As 34% of patients had a raised PIVKA-II, this suggests that vitamin K stores may be insufficient to maintain full gamma-carboxylation of prothrombin and emphasize the need to anticipate vitamin K deficiency in the ICU setting by appropriate supplementation.

Adolescent↗
PubMed2001

Ambulatory diagnoses-cluster statistics of patient visits at a clinic in the Amazon Region of Ecuador.

INTRODUCTION: Mondana Clinic is a small rural clinic located in the Napo river region of the Amazon basin in Ecuador. Since its opening in 1997 the clinic has grown to be the primary health care facility for approximately 3000 individuals. METHODS: A retrospective study was performed tabulating the ambulatory diagnosis, age, sex, and domicile of patients over a 9 month period in 1999. RESULTS: During the study period there were 765 patient visits that resulted in at least one diagnosis. Of the patient visits, 175 (22.8%) resulted in multiple diagnoses. Women accounted for 58% of the patient visits, which is similar to the 60% of ambulatory patient visits made in the USA by women. The age distribution showed 66% of patients were under 25 years of age. When comparing diagnoses of males with females, several differences were noted. As expected, urinary tract infections were approximately four-fold more common in females than in males. Gastritis and headaches were also more common reasons for patient visits in the female population than in the male. Conversely, lacerations, abrasions, and contusions ranked higher in the male than in the female population for patient visits. CONCLUSION: This study is the first to provide public health information for this region that will prove useful to the health professionals and funding agencies working in the region. Furthermore, it provides a baseline for comparison with other regions in Ecuador and South America in general, as well as comparisons with data-rich countries such as the USA.

Journal Article↗
PubMed2000

Improving the positive predictive value of screening for developmental language disorder.

In a previous study, we reported the results of an early language screening program in which 306 children were screened using a parent-report questionnaire sent through the mail (Klee et al., 1998). A sample of the children screened were given clinical evaluations within a month of screening (n = 64) and again 1 year later (n = 36). Although the screening program correctly identified 91% of 2-year-olds with language delay, it produced a large number of over-referrals. In the present study we examine a revised screening criterion designed to reduce the number of false positives. The revised criterion generated fewer positive screens overall than the original and resulted in improved specificity (96% vs. 87%) and positive predictive value (77% vs. 51%), while maintaining the high sensitivity (91%) and negative predictive value (98%) of the original criterion. We also propose a screening score based on the new criterion, designed to inform the process of deciding which children to bring in for further evaluation.

Child, Preschool↗
PubMed1999

One nurse's experience with technology.

This article examines the positive and negative aspects of working with a documentation and information management system from the unique perspective of a practicing home care nurse who was also a student. Aspects of the nightingale tracker technology that are comparable with others used in home care, experiences of field testing, and the nurse's observations can help home care nurses see how this technology can benefit their practice.

Attitude of Health Personnel↗
PubMed1998

The quality of life of older adults with urinary incontinence: determining generic and condition-specific predictors.

Urinary incontinence (UI) is an unpleasant problem for many adults. This study determined the importance of demographic, health and incontinence variables for the generic and incontinence-specific quality of life (QoL) of older adults (age > or = 60 years). Telephone surveys of adults reporting at least weekly episodes of UI (n = 435) were conducted as part of a randomized, controlled trial. Logistic regression analyses showed that the predictors of generic and incontinence-specific QoL differed. Life satisfaction, a generic outcome, was predicted by education, the number of days in bed due to health problems, the number of days not feeling well and the amount of urine lost. Generic health was related to education, the number of days sick in the previous 30 days and the number of days health issues restricted activities. The incontinence-specific QoL outcomes were predicted by age, mobility difficulties, the amount of urine lost, the frequency of UI, and the number of daytime and night-time voids. The specific QoL measures provide a different profile of those most affected in this sample than that obtained by the generic measures. The most affected are younger persons with severe urine loss. Older persons may have other conditions impinging on QoL and may have adapted behaviourally and psychologically to urine loss.

Aged↗
PubMed1997

Gamma delta T lymphocytes regulate the induction and maintenance of oral tolerance.

Oral administration of Ag, over a period of several days, induces a state of tolerance that is associated with activation of CD8+ T cells that can transfer unresponsiveness to naive syngeneic hosts. We previously demonstrated that these T cells are not CTL precursors and that they inhibit responses by CD8+ CTL, as well as Ab and CD4+ T cell responses. Activation of noncytolytic, CD8+ suppressor T cells by oral Ag is a process that is not understood. In these studies, we asked whether depletion of the gamma delta T cells altered induction of oral tolerance. Injection of the anti-delta-chain Ab (GL3) down-modulated the expression of gamma delta TCR and inhibited the induction of oral tolerance to OVA, as measured by Ab, CD4+, and CD8+ T cell responses. GL3 did not activate IL-2 secretion that could be detected in the serum, nor did it induce IL-2R expression by intraepithelial lymphocytes, suggesting that GL3 inhibited the function of gamma delta T cells rather than activating them. This interpretation is supported by our observation that oral administration of Ag did not induce tolerance in TCR-delta knockout mice. These data suggest that gamma delta T cells play a critical, active role in tolerance induced by orally administered Ag.

Animals↗
PubMed1996

Sleep history is neglected diagnostic information. Challenges for primary care physicians.

Sleep problems are treatable causes of morbidity and mortality, but little is known about how often the history fundamental to diagnosis is obtained. We recorded the frequency of sleep histories during encounters with simulated patients by 20 experienced primary care practitioners, 23 uninstructed medical interns, and 22 interns who had previous instruction about sleep disorders. Sleep histories were uncommonly obtained by uninstructed physicians (0% of practitioners, 13% of interns), but trained interns more often (81.8%) asked about sleep. If sleep problems are to be prioritized, major changes in physician education and behaviors are essential. Focused instruction about sleep influences physician behavior.

Education, Medical, Continuing↗
PubMed1996

Chemistry of muconaldehydes of possible relevance to the toxicology of benzene.

(Z,Z)-Muconaldehyde reacted with primary amines to give N-substituted-2(2'-oxoethyl)-pyrroles, which were reduced to N-substituted-2-(2'-hydroxyethyl)-pyrroles by sodium borohydride. The pyrrole-forming reaction is exhibited by valine and its methyl ester, and is being developed with terminal valine in hemoglobin as a means of dose monitoring (Z,Z)-muconaldehyde, a putative metabolite of benzene. Reactions in aqueous solution between (Z,Z)-muconaldehyde and adenosine, deoxyadenosine, guanosine, or deoxyguanosine leading to pyrrole-containing adducts are described. The elucidation of the structures of the adducts was assisted by the study of reactions between (Z,Z)-muconaldehyde and both nucleoside derivatives and a model compound for guanosine. Reactions of (Z,Z)-muconaldehyde are complicated by its isomerization to (E,Z)- and (E-E)-muconaldehyde. The kinetics of this process have been studied in benzene, acetonitrile, and dimethylsulfoxide.

Aldehydes↗
PubMed1995

Is the stroke belt disappearing? An analysis of racial, temporal, and age effects.

BACKGROUND AND PURPOSE: The stroke risk among white residents of the coastal plain of North Carolina, South Carolina, and Georgia (the "Stroke Belt") has been reported to be between 1.3 and 2.0 times the national average. In this study we examined (1) whether a similar excess risk exists for blacks in this region, (2) whether this regional excess stroke risk has decreased over time, and (3) whether the regional excess risk is consistent across ages from 45 to more than 85 years. METHODS: Using data from the Compressed Mortality File, we estimated the annual relative stroke mortality risk for black and white men and women in a region of 153 coastal plain counties and compared these rates to those for the remainder of the United States. RESULTS: The relative geographic excess risk of stroke death was similar for black residents and white residents of the Stroke Belt for both men and women. Despite the decline in stroke mortality, the relative increased risk of stroke death in the region has remained constant from 1968 to 1991; however, the pattern of excess risk across age differed significantly between race/sex groups. CONCLUSIONS: These data show that the Stroke Belt continues to exist for blacks and whites and for men and women. Although the specific causes of the Stroke Belt remain unknown, the public health impact is staggering, with a greater than 40% excess risk of stroke mortality and more than 1200 excess stroke deaths annually.

Age Factors↗
PubMed1990

Adverse learning strategy: the Adelaide Diagnostic Learning Inventory and its subscale replicability in a medical student population.

The Adelaide Diagnostic Learning Inventory (ADLIMS) is a measure of learning styles and learning pathologies that was designed to investigate the impact of traditional approaches to learning versus problem-based learning and to identify students whose approach to learning tasks predicted poor academic performance. In this study, some important psychometric properties of the ADLIMS were examined, including its factor structure. In this study, factor replicability across samples was argued to provide a more robust and psychologically meaningful factor solution than that which can be obtained using traditional mathematical criteria. The results of the factor analysis did not confirm the presence of the four factor solution earlier reported for the ADLIMS, but did identify three clear factors that had very high replicability. An inspection of the items comprising these three factors showed that factor 1 tapped subjective distress related to poor study habits, lack of motivation to study, and distraction from social activities. Factor 2 tapped distress arising from high achievement expectations that were hampered by superficial or disorganized study habits that did not enable the student to grasp the relationships between concepts and ideas. Factor 3 tapped positive feelings and a sense of satisfaction associated with a problem-based approach to the learning of new study material. Although the internal reliability of the ADLIMS subscales met the requirements of a measure to be used in general research such as in the investigation of correlates among groups of medical students, they did not meet the higher requirements of a measure to be used to identify or predict individuals with pathological learning styles.

Humans↗
PubMed1989

The mobilization of ferritin iron by liver cytosol. A comparison of xanthine and NADH as reducing substrates.

Considerable evidence suggests that the release of iron from ferritin is a reductive process. A role in this process has been proposed for two hepatic enzymes, namely xanthine oxidoreductase and an NADH oxidoreductase. The abilities of xanthine and NADH to serve as a source of reducing power for the enzyme-mediated release of ferritin iron (ferrireductase activity) were compared with turkey liver and rat liver homogenates. The maximal velocity (Vmax.) for the reaction with NADH was 50 times greater than with xanthine; however, the substrate concentration required to achieve half-maximal velocity (Km) was 1000 times less with xanthine than with NADH. NADPH could be substituted for NADH with little loss in activity. Dicoumarol did not inhibit the reaction with NADH or NADPH, demonstrating that the ferrireductase activity with those substrates was not the result of the liver enzyme 'DT-diaphorase' [NAD(P)H dehydrogenase (quinone)]. A flavin nucleotide was required for ferrireductase activity with rat and turkey liver cytosol when xanthine, NADH or NADPH was used as the reducing substrate. FMN yielded twice the activity with NADH or NADPH, whereas FAD was twice as effective with xanthine as substrate. Kinetic comparisons, differences in lability and partial chromatographic resolution of the ferrireductase activities with the two types of reducing substrates strongly indicate that the ferrireductase activities with xanthine and NADH are catalysed by separate enzyme systems contained in liver cytosol. Complete inhibition by allopurinol of the ferrireductase activity endogenous to undialysed liver cytosol preparations and the ability of xanthine to restore equivalent activity to dialysed preparations indicate that the source of reducing power for the endogenous activity is xanthine. These studies suggest that xanthine, NADH or NADPH can serve as a source of reducing power for the enzyme-mediated reduction of ferritin iron, with a flavin nucleotide serving as the shuttle of electrons from the enzymes to the ferritin iron.

Animals↗
PubMed1985

Self-awareness and self-confrontation: effects of self-focused attention on members of a clinical population.

Research in the area of self-awareness theory has indicated that self-focused attention consistently produces both an increase in perceived intensity of affect and enhanced accuracy of self-reports. The present studies consider these effects in relation to the technique of self-confrontation as used in psychotherapy. In the first study, members of two different clinical populations (alcoholics and general psychiatric patients) either were or were not made self-aware and then were asked to self-report on their psychiatric problems and their mood states. Results indicated that self-awareness did increase the negative mood states for the psychiatric patients, and it also apparently increased the accuracy with which both patient groups reported on their history of hospitalization. In the second study self-awareness once again exacerbated the reported negative affect of a group of depressed psychiatric patients and enhanced the accuracy with which they reported on their hospitalizations. Additional analyses indicated that although the psychiatric patients generally felt worse when self-aware, they were also more accurate in their self-reports, including descriptions of their problems. The effects of self-awareness on members of clinical population are discussed and related to self-confrontation techniques.

Adult↗