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Biomedical subjects

K M Butler

Publications and source records attributed to K M Butler.

At least 19 recordsLinked to original sources
PubMed2001

A limit on retrieval-induced forgetting.

Retrieving some members of a memory set impairs later recall of semantically related but not unrelated members (M. C. Anderson, R. A. Bjork, & E. L. Bjork, 1994; M. C. Anderson & B. A. Spellman, 1995). The authors investigated whether this retrieval-induced forgetting effect would generalize to testing procedures other than category-cued recall. Although the authors demonstrated a retrieval-induced forgetting effect using a category-cued recall task, they failed to show retrieval-induced forgetting on several different memory tests that used item-specific cues, including a category-plus-stem-cued recall test, a category-plus-fragment-cued recall test, a fragment-cued recall test, and a fragment completion task.

Adult↗
PubMed2001

Planning and execution of a successful hepatitis B immunization program.

Today's college students occupy a "window" between older adults, whose need for hepatitis B vaccination is minimal, and younger people who receive the vaccine as part of their childhood immunization series. However, because of the high-risk activities that are often part of student behavior, college students are among the individuals who are at the highest risk for this disease; 75% of all reported hepatitis B cases occur in persons between the ages of 15 and 39 years. It is therefore imperative that college health professionals take seriously their responsibility to educate students about issues related to hepatitis B and make available programs that enable the students to receive immunizations. This article briefly describes a successful hepatitis B education and immunization program at an institution that has no mandatory prematriculation immunization requirements.

Adolescent↗
PubMed2001

Antenatal hepatitis B screening - is there a need for a national policy?

Routine antenatal testing for hepatitis B carriage with maternal consent was introduced at the Rotunda in January 1998. The uptake of testing has been excellent; 99.98% of women presenting for antenatal care accepted hepatitis B (HBV) screening in the 30-months from January 1998 through June 2000. The prevalence of HBV carriage was 0.35% (58 pregnancies of 16,222 tested) increasing from 0.25% in 1998 (16 of 6227) to 0.45% in the first six months of 2000 (16 of 3484). Fifty-five women had 58 pregnancies (three women had two pregnancies). Two of these were e-antigen positive. HBV carrier status was previously unknown in 48 (87%). Two additional women had acute HBV infection in pregnancy. Forty-five infants have been born to mothers included in this screening programme. Audit of infant outcome reveals excellent compliance with immunisation and follow-up: 29 (64%) have completed the 3 dose HBV vaccination schedule to date. Thirteen infants (31%) are still attending; three are lost to follow-up including one whose family has emigrated. Routine antenatal screening for hepatitis B carriage is cost-effective and should be considered a standard of care in maternity practice.

Carrier State↗
PubMed2000

The efficacy and tolerability of combination antiretroviral therapy in pregnancy: infant and maternal outcome.

Antiretroviral therapy (ART) and Caesarean section (CS) delivery significantly reduce the risk of vertically transmitted HIV infection. Attention must focus on determining the optimal management strategy for HIV-positive pregnancies. Guidelines must reflect not only the activity and tolerability of combination ART in pregnancy for mother and infant and the potential short and long-term infant toxicity, but also whether surgical delivery can confer an added benefit if combination ART had reduced plasma viraemia to undetectable levels. To aid the development of management strategies for the Republic of Ireland, a retrospective detailed review of all HIV-positive pregnancies since the introduction of combination ART was undertaken. Since 1997 there have been 25 deliveries to 24 women. Combination ART reduced plasma viraemia to undetectable levels in 76% mothers at delivery. The CS rate was 28% and no unanticipated infant toxicity was encountered. To date no infant has proven infected. Three infants have seroreverted and 24 of 26 infants have had at least 2 negative HIV ribonucleic acid (RNA) and polymerase chain reaction (PCR) tests. Two infants are less than one month old. In this study, the CS rate of 28% is below that reported from many centres yet no vertical transmission was found. Given the efficacy of ART in reducing plasma viraemia, the additional benefit of CS for these women is questionable.

Adolescent↗
PubMed1999

Accidental exposures to blood and other body fluids in a large academic medical center.

Healthcare workers' and students' exposures to blood-borne pathogens during a 1-year period (1997) at a large university academic medical center were analyzed. The university health manages the Blood-Borne Pathogen Post-Exposure Control Program at the university and treats all reported exposures of students, faculty, and staff. Comparative exposure rates for all categories of healthcare workers, the work site where injuries occurred, and the circumstances involved in 298 exposure incidents are outlined. A standardized postexposure prophylaxis protocol provides for definition of the health status of all known source patients and assessment of the potential need for treatment of the exposed clinician. Implications of the study for focusing on improvements in training healthcare workers in proper procedures and the use of personal protective equipment in dealing with blood-borne pathogens are discussed.

Blood-Borne Pathogens↗
PubMed1999

Suppression of reflexive saccades in younger and older adults: age comparisons on an antisaccade task.

Inhibitory control of prepotent responses has been examined by using the antisaccade task, during which a reflexive saccade toward a peripheral onset must be suppressed before an eye movement in the opposite direction from the onset can be executed. In the present experiments, we sought to determine whether older and younger adults would perform similarly on this task. Older adults had a harder time suppressing their reflexive responses, as measured by an increase in the proportion of saccade direction errors. Despite an age-related decline in saccade direction accuracy, the increase in saccade latency associated with the antisaccade condition was the same for both younger and older adults. These results support the view that the effectiveness of inhibitory control declines with age (Hasher & Zacks, 1988; Hasher, Zacks, & May, 1999).

Adolescent↗
PubMed1998

Paediatric HIV infection in the Republic of Ireland and the need for antenatal screening.

Thirty-seven HIV-infected children have been identified in the Republic of Ireland since 1985. Only 12 (32%) of 37 were followed prospectively from birth. Median age at diagnosis was 18 months (4 weeks to 8 years). In 32 (86%) of 37 cases, HIV infection was acquired as a result of transmission from mother to infant with intravenous drug use (IVDU) the most frequent risk factor for maternal acquisition of HIV. Of these 32 children, median maternal age at delivery was 24 (interquartile range (IQR) 23-26) years with median gestation at delivery 40 (IQR 38-40) weeks. Mode of delivery was by vaginal delivery in all 29 (91%) cases where mode of delivery is known. Only 2 infants were breastfed. Seven children have died at a median age of 9 (0.8-9.6) years. As of July 1997, 12 children have AIDS, 14 have symptomatic disease without AIDS and 3 are asymptomatic. Median age at AIDS diagnosis was 2.6 (0.1-6.5) years. Median survival time post-AIDS diagnosis was 6.5 (1.8-8.3) years. Of 29 living children, 24 mothers and 14 fathers are HIV infected and only 14 children live with both parents. Childhood HIV infection has had a significant personal, social and financial impact on both Irish families and society in general. More effective measures to control HIV infection among intravenous drug users are needed. Antenatal detection of HIV-infected mothers is paramount as vertical transmission can be successfully prevented and morbidity and death can be prevented in the infected infant.

Child↗
PubMed1997

Childhood needlestick injuries in the Dublin metropolitan area.

Childhood needlestick injuries and other risk exposures outside of hospital are becoming increasingly common. A retrospective review of casenotes to ascertain the incidence, epidemiology and adequacy of management and follow-up of exposures in the Dublin metropolitan area revealed 52 cases between July 1995 and October 1996. Median age of children was 7.4 years. Most occurred in inner city areas with a recognised high prevalence of i.v. drug use. Only 2 high-risk exposures were identified. On presentation all cases received Hepatitis B vaccination and 56% received Hepatitis B immunoglobulin. Following Hepatitis B virus, Hepatitis C virus and Human immunodeficiency virus testing, no seroconversions have been identified to date in 9 children with completed tests. General follow-up and Hepatitis B immunisation when initiated were not always complete. Standardised management protocols and wider availability of counselling are recommended.

Adolescent↗
PubMed1996

Cryptosporidiosis in children who visited an open farm.

In the summer of 1995, cryptosporidiosis was diagnosed in a child in hospital. This child had taken part in a summer activity project involving 161 children and nine adults. Reports of a similar illness among a number of other participants prompted an outbreak investigation. A cohort study was conducted in two phases. Thirteen children (aged 6 to 15 years) out of 161 respondents to the first questionnaire met the case definition for illness and cryptosporidium was detected in stools from seven of the 13. Illness was significantly associated with child participants who had visited an open farm (p < .000005). Nine of the cases sought medical attention, and two were admitted to hospital. The second phase of the cohort study was conducted among 52 of the 55 people who had visited the open farm. Illness was significantly associated with playing in sand to which animals had access, at the edge of a stream beside a picnic area (p < .005). Contact with various animals was not associated with illness. This outbreak emphasises the risk for children of visiting open farms. Managers of open farms need to be aware of the potential for transmission of infectious diseases to visiting children. Strict implementation of hygiene measures is essential to minimise risk.

Adolescent↗
PubMed1994

Clinical and pharmacokinetic evaluation of long-term therapy with didanosine in children with HIV infection.

BACKGROUND: Didanosine has demonstrated promising antiviral activity and a tolerable toxicity profile in short term studies. We describe a cohort of HIV-infected children who were treated for a prolonged period of time with didanosine. METHODS: Children (6 months to 18 years of age) with symptomatic HIV infection or an absolute CD4 count < 0.5 x 10(9) cells/L, received oral didanosine at doses between 20 mg/m2 to 180 mg/m2 every 8 hours. Clinical, immunological, and virological parameters were assessed at least every 2 months. The pharmacokinetics of didanosine were evaluated in 85 patients. RESULTS: Previously untreated children (n = 51) and children who had received prior antiretroviral therapy (n = 52) were enrolled in the study (median time on study 22.6 months; range 2 to 48). The long-term administration of didanosine was well tolerated and no new toxicities were observed. The absolute CD4 count increased by > or = .05 x 10(9) cells/L in 28 of 87 (32%) of patients after 6 months of therapy. Responses were also sustained in 41% of these children after 3 years of therapy. Children entering the study with a CD4 count > 0.1 x 10(9) cells/L (n = 51) had a marked survival advantage (P = .00002) with an estimated survival probability after 3 years of 80% compared to 39% for children with lower CD4 counts. Although the area under the curve of didanosine increased proportionally with the dose, there was considerable interpatient variability at each dose level. There was no apparent relationship between surrogate markers of clinical outcome and plasma drug concentration. CONCLUSIONS: Didanosine was well tolerated with chronic administration, and toxicities were uncommon and usually reversible. In 41% of patients, the CD4 count increased and was maintained at the higher level even after years of treatment.

Adolescent↗
PubMed1993

High-level resistance to zidovudine but not to zalcitabine or didanosine in human immunodeficiency virus from children receiving antiretroviral therapy.

Human immunodeficiency virus type 1 (HIV-1) isolates from children receiving long-term therapy with an alternating regimen of zidovudine and zalcitabine, or with didanosine monotherapy, were evaluated for resistance to zidovudine, zalcitabine, and didanosine, and for mutations known to be associated with zidovudine or didanosine resistance. HIV-1 from four of six patients receiving zidovudine with zalcitabine developed high-level resistance to zidovudine. A mutation in the HIV-1 reverse transcriptase that is highly associated with zidovudine resistance was identified in all four zidovudine-resistant posttherapy isolates. In contrast, none of the HIV-1 isolates from the seven patients receiving didanosine developed high-level resistance to this agent, despite the identification of a didanosine-associated mutation in six of these posttherapy isolates, although small decreases in sensitivity to didanosine were observed. These results indicate that nucleoside analog-associated mutations in HIV-1 occur frequently in children receiving long-term antiretroviral therapy and that alternating combination therapy does not prevent the development of resistance to zidovudine. They also suggest that there may be differences in the degree of resistance conferred by mutations that result from therapy with different nucleoside analogs. These findings underscore the need for studies to define the clinical importance of these mutations, and for treatment strategies to overcome the emergence of viral resistance in vivo.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Pancreatitis in human immunodeficiency virus-infected children receiving dideoxyinosine.

To define predictive or contributory risk factors for pancreatitis in human immunodeficiency virus-infected children receiving dideoxyinosine (ddI), the authors evaluated 95 children, 3 months to 18 years of age, who had received ddI at 60 to 540 mg/m2 per day for a mean of 56 weeks. Pancreatitis developed in 7 patients (7%) but resolved in all upon withdrawal of ddI. Neither age, sex, nor CD4 count at study entry was predictive of pancreatitis, but pancreatitis appeared more likely to develop in hemophiliacs than in other patients (4 of 23 vs 3 of 72). Pancreatitis developed only in patients who received ddI at the highest dose levels (7 of 60 patients who received ddI at a dose > or = 360 mg/m2 per day vs 0 of 35 patients who received < or = 270 mg/m2 per day). Patients in whom pancreatitis developed had received a higher mean daily dose of ddI than patients with normal amylase and lipase levels throughout the study (348 mg/m2 vs 282 mg/m2), but no relationship with the cumulative dose or the duration of ddI therapy was observed. Although a statistically significant relationship between ddI plasma concentration (area under the curve) and pancreatitis was not conclusively demonstrated, as the number of patients in whom pancreatitis actually developed was small, such a relationship may have been obscured.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Changes in T-helper cell function in human immunodeficiency virus-infected children during didanosine therapy as a measure of antiretroviral activity.

Didanosine has shown activity against the human immunodeficiency virus (HIV) in both children and adults. We prospectively assessed T-helper cell (Th) function as determined by in vitro interleukin-2 (IL-2) production in response to a panel of T-cell stimuli in 22 HIV-infected children before and during didanosine therapy and we correlated the incidence of opportunistic and recurrent bacterial infections with changes in p24 antigen and CD4 counts. Didanosine (270, 360, or 540 mg/m2/d) was administered orally for periods ranging from 8 to 40 weeks (mean, 24 weeks). Five of six asymptomatic patients (Centers for Disease Control P-1) compared with 6 of 16 symptomatic (P-2) patients exhibited improved Th function (greater than threefold increase in IL-2 production to at least 2 of the 4 stimuli) during therapy. Of 12 patients without infections during therapy, 9 (75%) showed improvement in Th function, compared with only 2 of 10 patients with infections (P = .03). Notably, the incidence of infections was not correlated with improvements in CD4 count or decreases in p24 antigen. Improvement in Th function during didanosine therapy is correlated with decreased incidence of infections. Assessment of Th function may provide an additional measurement of immunologic response to antiretroviral therapy.

Adolescent↗
PubMed1992

Retinal toxicity in human immunodeficiency virus-infected children treated with 2',3'-dideoxyinosine.

To assess the safety and antiretroviral activity of 2',3'-dideoxyinosine, we enrolled 43 children with symptomatic (Centers for Disease Control class P-2) human immunodeficiency virus infection in a Phase I-II study and monitored them prospectively for the development of ocular complications secondary to HIV infection or drug toxicity. Follow-up ranged from 12 to 103 weeks with a median follow-up of 71 weeks. Three of 43 children (7.0%) developed peripheral atrophy of the retinal pigment epithelium during treatment with 2',3'-dideoxyinosine. The two children with the most severe retinal atrophy were enrolled in the study at the highest dosage studied (540 mg/m2/day). In contrast to findings in children, no retinal atrophy in HIV-infected adults treated with 2',3'-dideoxyinosine has been evident to date.

Atrophy↗
PubMed1992

CD4 status and P24 antigenemia. Are they useful predictors of survival in HIV-infected children receiving antiretroviral therapy?

OBJECTIVE: To determine the relationship between CD4 status and the P24 antigen level and survival in children infected with the human immunodeficiency virus. DESIGN: Cohort, case-control. SETTING: Clinical Center at the National Institutes of Health, Bethesda, Md. PARTICIPANTS: One hundred forty-seven children infected with the human immunodeficiency virus enrolled in antiretroviral therapy protocols at the National Cancer Institute were reviewed and the relationships between CD4 counts, P24 antigenemia, and death were analyzed. INTERVENTIONS: None. MEASUREMENTS/MAIN RESULTS: The presence of a very low CD count, less than 21% of the lower limit of normal values for age (equivalent to 0.05 x 10(9)/L in an adult), was associated with a significantly increased risk of death within 2 years. Although the risk of death was highest for children with CD4 counts below this level and who had detectable P24 antigen levels, P24 antigenemia by itself contributed little to the prognostic value of the CD4 count alone. However, it was also notable that a group of children with low CD4 counts also experienced prolonged survival. CONCLUSIONS: The association between low CD4 counts and death suggests that the age-adjusted CD4 count should be used as a marker to guide therapeutic intervention. At the same time, the presence of a very low CD4 count alone should not be considered a reason for therapeutic nihilism.

Age Factors↗
PubMed1992

Cerebral artery aneurysms in children infected with human immunodeficiency virus.

More than 250 children treated at our institution on antiretroviral treatment protocols have been monitored with brain imaging studies. We documented the occurrence and progression of aneurysms of major cerebral arteries in two children with advanced human immunodeficiency virus infection. In both cases these lesions remained clinically silent initially, despite progression to marked dilation.

Brain↗
PubMed1992

Treatment of aggressive cytomegalovirus retinitis with ganciclovir in combination with foscarnet in a child infected with human immunodeficiency virus.

Ganciclovir and foscarnet are both effective for cytomegalovirus retinitis in patients with acquired immunodeficiency syndrome, but the benefits of either agent given alone are limited. A child infected with human immunodeficiency virus who had cytomegalovirus retinitis that progressed despite treatment with either agent alone received the combination of ganciclovir and foscarnet. This treatment resulted in a sustained clinical response.

Antiviral Agents↗