Biomedical subjects

K Butler

Publications and source records attributed to K Butler.

At least 19 recordsLinked to original sources

PubMed2006

Complications associated with the bacille Calmette-Guérin vaccination in Ireland.

INTRODUCTION: BCG vaccination is currently recommended for all newborns in Ireland except where specifically contraindicated. This paper describes a marked increase in the number of referrals of patients with localised complications after vaccination to two Dublin paediatric hospitals. This increase coincided with the introduction of a new strain of BCG vaccine METHODS: A population surveillance study was undertaken to determine the frequency and spectrum of complications associated with the new strain of BCG vaccine introduced in Ireland. Patients were identified though review of the infectious disease service case records and microbiology laboratory culture reports for the two year period from August 2002 to July 2004. Prospectively gathered data were supplemented by retrospective chart review. All infants who had inoculation site abscesses, suppurative adenopathy, or non-suppurative adenopathy with nodes > or =2 cm were included. RESULTS: Fifty eight patients presented a median of 13 weeks post-inoculation: 32 with suppurative adenitis, 17 with inoculation site abscess, three with both inoculation site abscess and suppurative adenitis, and six with non-suppurative adenopathy. The overall complication rate was estimated at 1/931 vaccinees with 1/1543 developing suppurative adenitis. Twenty six infants required surgery. DISCUSSION: This series illustrates the role of hospitals in sentinel surveillance and highlights the importance of having a well functioning and responsive system of adverse event reporting. These events raise a serious question as to the suitability of this vaccine strain for use in a national immunisation programme in a country where the prevalence of tuberculous disease is 10.4/100,000.

Abscess↗

PubMed2006

National guidelines for the management of HIV-1 in pregnancy.

Management of HIV-1 in pregnancy has reduced the mother-to-child-transmission (MTCT) rate from 25-30% to <2% in the developed world, including Ireland. In Ireland most HIV positive pregnant women are diagnosed through antenatal screening many of whom arrive here late in pregnancy. Geographic dispersal and subsequent involvement of obstetric units throughout the country has resulted in a need for clear, accessible management guidelines. The Irish Infection Society first published guidelines for the management of HIV-1 in pregnancy in 2001 (1). The updated guidelines became operational in January 2002 with some amendments in March 2003 and July 2004. These guidelines offer a broad management outline for HIV positive pregnant women. Ultimately, each woman is assessed individually by a multidisciplinary team and a careful plan is determined.

Anti-Retroviral Agents↗

PubMed2005

Antileukemic effect of daclizumab in CD25 high-expressing leukemias and impact of tumor burden on antibody dosing.

Humanized anti-CD25 antibody, daclizumab, was applied in a pilot study of 10 patients with CD25(+) leukemias and pharmacokinetic/pharmacodynamic properties were characterized. Two widely held concepts - tumor sink accelerating pharmacokinetics and higher antigen expression correlating with target cell clearance - were supported by this first systematic evaluation of these questions with actual human clinical data. A flexi-dosing regimen was validated for maintaining target drug levels in vivo with a wide range of tumor burdens. Daclizumab induced clearance of peripheral leukemic cells when highly positive for CD25, but durable responses were not obtained. If daclizumab will have a role in antileukemic therapy, it may be in minimal disease settings or as a component of a combination regimen, but only when CD25 expression is high.

Adult↗

PubMed2004

Accuracy, efficiency and robustness of four algorithms allowing full sibship reconstruction from DNA marker data.

In the problem of reconstructing full sib pedigrees from DNA marker data, three existing algorithms and one new algorithm are compared in terms of accuracy, efficiency and robustness using real and simulated data sets. An algorithm based on the exclusion principle and another based on a maximization of the Simpson index were very accurate at reconstructing data sets comprising a few large families but had problems with data sets with limited family structure, while a Markov Chain Monte Carlo (MCMC) algorithm based on the maximization of a partition score had the opposite behaviour. An MCMC algorithm based on maximizing the full joint likelihood performed best in small data sets comprising several medium-sized families but did not work well under most other conditions. It appears that the likelihood surface may be rough and presents challenges for the MCMC algorithm to find the global maximum. This likelihood algorithm also exhibited problems in reconstructing large family groups, due possibly to limits in computational precision. The accuracy of each algorithm improved with an increasing amount of information in the data set, and was very high with eight loci with eight alleles each. All four algorithms were quite robust to deviation from an idealized uniform allelic distribution, to departures from idealized Mendelian inheritance in simulated data sets and to the presence of null alleles. In contrast, none of the algorithms were very robust to the probable presence of error/mutation in the data. Depending upon the type of mutation or errors and the algorithm used, between 70 and 98% of the affected individuals were classified improperly on average.

Algorithms↗

PubMed2003

Decline in mortality, AIDS, and hospital admissions in perinatally HIV-1 infected children in the United Kingdom and Ireland.

OBJECTIVE: To describe changes in demographic factors, disease progression, hospital admissions, and use of antiretroviral therapy in children with HIV. DESIGN: Active surveillance through the national study of HIV in pregnancy and childhood (NSHPC) and additional data from a subset of children in the collaborative HIV paediatric study (CHIPS). SETTING: United Kingdom and Ireland. PARTICIPANTS: 944 children with perinatally acquired HIV-1 under clinical care. MAIN OUTCOME MEASURES: Changes over time in progression to AIDS and death, hospital admission rates, and use of antiretroviral therapy. RESULTS: 944 children with perinatally acquired HIV were reported in the United Kingdom and Ireland by October 2002; 628 (67%) were black African, 205 (22%) were aged > or = 10 years at last follow up, 193 (20%) are known to have died. The proportion of children presenting who were born abroad increased from 20% in 1994-5 to 60% during 2000-2. Mortality was stable before 1997 at 9.3 per 100 child years at risk but fell to 2.0 in 2001-2 (trend P < 0.001). Progression to AIDS also declined (P < 0.001). From 1997 onwards the proportion of children on three or four drug antiretroviral therapy increased. Hospital admission rates declined by 80%, but with more children in follow up the absolute number of admissions fell by only 26%. CONCLUSION: In children with HIV infection, mortality, AIDS, and hospital admission rates have declined substantially since the introduction of three or four drug antiretroviral therapy in 1997. As infected children in the United Kingdom and Ireland are living longer, there is an increasing need to address their medical, social, and psychological needs as they enter adolescence and adult life.

Acquired Immunodeficiency Syndrome↗

PubMed2001

Motivations and psychosocial impact of genetic testing for HNPCC.

A type of hereditary colorectal cancer (CRC) known as hereditary nonpolyposis colorectal cancer (HNPCC) is associated with MLHI and MSH2 gene mutations. This study consists of a pilot, cross-sectional study of 50 individuals who were engaged in the genetic testing process for HNPCC. The study investigated the motivations and attitudes around genetic testing and current psychosocial functioning through the use of standardized measures, as well as obtained information on disclosure patterns associated with test results. The mean age of the sample was 44.3 years. (SD = 15.0). Twenty-three individuals were identified as "carriers" (13 had a previous history of CRC), seven were "non-carriers" and 20 individuals were still awaiting test results. The primary motivations for participating in genetic testing were similar to previous reports and included: wanting to know if more screening tests were needed, obtaining information about the risk for offspring and increasing certainty around their own risk. The psychosocial scores demonstrated that a subgroup of individuals exhibited distress, with greater distress for those individuals awaiting results or testing positive. There was a high level of satisfaction associated with the experience of testing. Individuals in this study tended to disclose their test results to a variety of family and non-family members. Disclosure was primarily associated with positive experiences however, some individuals reported regret around disclosure of their results. These preliminary findings should be further explored in a larger prospective study design over multiple time points.

Adult↗

PubMed2001

Nonradioactive in situ hybridization to xenopus tissue sections.

We describe a protocol for the localization of specific messenger RNAs in Xenopus laevis embryo tissue sections using a nonradioactive detection method. After fixation, embryos are embedded in paraffin wax, sectioned, mounted on slides, and subjected to a series of prehybridization treatments which improve the accessibility of the probe to the target mRNA and reduce nonspecific binding. These treatments are followed by hybridization in situ with single-stranded antisense RNA probe generated by in vitro transcription and labeled with digoxigenin. The hybridization products are detected with preabsorbed alkaline phosphatase-coupled digoxigenin antibody and subsequently localized using a chromogenic substrate that generates a colored precipitate at the hybridization site. The nonradioactive in situ hybridization method we describe is reproducible and has a detection sensitivity akin to those methods that use antisense RNA probes labeled with radioisotopes; however, it is faster, safer, and easier to perform. Sectioning of prestained whole-mount X. laevis embryos does not always show the complete expression pattern of many genes, particularly those in deep endodermal structures, due to inadequate probe penetration. Therefore thorough analysis of gene expression patterns often requires in situ hybridization on presectioned material whereby probe has equal accessibility to all tissue.

Animals↗

PubMed2001

Rhinocerebral zygomycosis in childhood acute lymphoblastic leukaemia.

The hazards associated with invasive candidiasis and aspergillosis in oncology patients are well recognised. These conditions typically present late in treatment, often after prolonged or recurrent episodes of neutropenia. We report the occurrence of Absidia corymbifera infection causing rhinocerebral zygomycosis in two children with acute lymphoblastic leukaemia, early in the induction phase of treatment and within a 3-month interval, in the same oncology unit. The initial presentation of facial pain was rapidly followed by the development of cranial nerve palsies, cavernous sinus thrombosis, diabetes insipidus, seizures and death within 9 days of symptom onset, despite aggressive management with high-dose liposomal amphotericin (Ambisome), surgical debridement and local instillation of amphotericin solution. These cases highlight the need for awareness of zygomycosis as a potentially lethal fungal infection that can present even with short duration exposure to the usual risk factors. Their occurrence within a limited time period raises questions as to the relative importance of environmental exposure. The failure of medical and surgical intervention to impact on the course illustrates the need to develop appropriate preventative strategies which may have to incorporate measures to reduce the environmental exposure of susceptible patients.

Absidia↗

PubMed2001

Heart function challenged with beta-receptor agonism or antagonism in a heart failure model.

We have shown that chronic treatment with carteolol, a non-selective beta-adrenergic receptor antagonist, improved left ventricular (LV) function and survival in an avian model of dilated cardiomyopathy (DCM). The aim of the present study was to compare ex vivo heart function with and without beta-agonist and antagonist challenge. We investigated whether intracoronary infusion of a beta-blocker, carteolol or beta-agonist, isoproterenol decreased contractility. In the DCM group, isoproterenol resulted in a significantly greater increase in heart rate (71% vs. 28% compared to control hearts). To investigate the mechanism for the increase in heart rate, we exposed spontaneously beating neonatal cardiomyocytes to serum immunoglobulin (IgG) isolated from DCM animals. Serum IgG resulted in a significant increase in spontaneous beating rate in neonatal rat cardiomyocytes that was blocked by pre-treatment with a beta-blocker. Carteolol challenge did not significantly change heart rate but did significantly increase LV peak pressure in DCM hearts (62%) while coronary artery flow remained unchanged (2.7+/-0.1 vs 2.7+/-0.5 ml/min/g). These results show that 1) beta-receptor stimulation results in a greater tachycardic response in DCM animals, and 2) carteolol challenge improves myocardial contractility in hearts from DCM animals independent of heart rate or changes in coronary artery flow.

Adrenergic beta-Agonists↗

PubMed2001

Quality of life and psychosexual adjustment after prophylactic oophorectomy for a family history of ovarian cancer.

OBJECTIVES: 1) To evaluate a woman's satisfaction with the decision to have a prophylactic oophorectomy for family history of ovarian cancer. 2) To explore the potential costs related to surgery such a menopausal symptoms and satisfaction with sexual functioning. METHODS: Women who had undergone a prophylactic oophorectomy for a family history of ovarian cancer in Ontario were invited to participate. Forty women returned a package of questionnaires addressing demographic information, family history, decisional conflict, risk comprehension, menopause-specific quality of life, satisfaction with sexual function, and other psychosocial questionnaires. RESULTS: The mean age of respondents was 54.8 years. Perceived risk for developing ovarian cancer decreased significantly after surgery (p = 0.0001). Overall quality of life on the SF-36 Health Survey demonstrated a level consistent with emotional and physical wellbeing in the general population. The Menopause-Specific Quality of Life scores were reduced compared to women of similar age on all parameters: vasomotor symptoms, psychosocial support, physical status and sexual quality of life. Satisfaction with sexual functioning was moderately to extremely compromised in 42.1%-53.7% of women. CONCLUSION: While this study shows that women who choose to have prophylactic oophorectomy for a family history of ovarian cancer have a good overall quality of life and significant decrease in risk perception as a result of surgery, they experience menopausal symptoms and compromised sexual functioning.

Adaptation, Psychological↗

PubMed2001

The Heartmate II: design and development of a fully sealed axial flow left ventricular assist system.

Our group is developing the control and power transmission components required to implement a permanent and fully sealed left ventricular assist system (LVAS). Starting with the percutaneously powered HeartMate II blood pump, our development efforts are focused in the following areas: a complete redesign of the transcutaneous energy transmission system (TETS) to include a rectification network and autonomous voltage regulation within the secondary coil, a hermetically sealed electronics package containing a miniaturized implementation of the existing redundant drive and control electronics with several power-input options, an implanted rechargeable lithium ion battery pack capable of providing up to 1 h of untethered operation, implantable electrical connectors that allow components to be connected after placement in the body or to be replaced if needed, and a radio telemetry subsystem to transmit diagnostic information and to permit remote adjustment of selected parameters.

Electric Power Supplies↗

PubMed2001

Cytological evaluation of the tissue-implant reaction associated with S/C and I/P implantation of ALCAP and HA bioceramics in vivo.

It is well documented that several ceramic materials are highly compatible and non-immunogenic with host tissues. Recent studies have demonstrated the need for further investigation of these devices in vivo to further elucidate the possible mechanisms involved in biocompatibility. The purpose of this investigation was to study the morphological characteristics of the fibrous tissue capsule resulting from the implantation of aluminum calcium phosphate (ALCAP) and hydroxyapetite (HA) bioceramics. Implants of ALCAP and HA were implanted into 10 adult male rats subcutaneously (S/C) and intraperitoneally (I/P). At 90 days post-implantation, the animals were euthanized, and the ceramic devices, the fibrous tissue, and vital organs were harvested. Evaluation of routine stained sections (5 microm, hematoxylin & eosin) of the fibrous tissue capsule surrounding the HA and ALCAP ceramics revealed the following: 1) all the ceramic devices had fibrous connective tissue capsules of slightly varying degrees of thickness at the time of sacrifice, depending on the site of implantation and type of material, and 2) there were statistically significant differences (p < 0.05) in the numbers and types of cellular components with respect to implantation site. The number of macrophages, neutrophils, fibroblasts, degree of vascularity, and thickness of the fibrous tissue matrix was found to be statistically different between the S/C implanted ceramic groups. The number of macrophages, neutrophils, fibroblasts, and collagen content comparing the fibrous tissue surrounding the ALCAP and HA ceramics (I/P), was found to be statisically different.

Aluminum Compounds↗

PubMed2001

Potentiation of vincristine toxicity by itraconazole in children with lymphoid malignancies.

UNLABELLED: Eight consecutive paediatric patients with acute lymphoblastic leukaemia (ALL) (n = 7) and T-cell non-Hodgkin's lymphoma (NHL) (n = 1) presenting within a 5-wk interval were started on a standard induction protocol which included weekly treatment with vincristine for 4 wk. Itraconazole was commenced as antifungal prophylaxis, 1-21 d after the first injection of vincristine. Within 2 to 4 wk, enhanced vincristine neurotoxicity was noted in all patients, abdominal cramps and constipation occurred most frequently, and one patient developed a bowel perforation associated with paralytic ileus. Hyponatraemia associated with SIADH was observed in three patients and four patients developed seizures. An additional patient with B cell NHL developed seizures 5 d after an injection of vincristine. Recovery was complete in all patients and ranged from 2 d to 15 wk. CONCLUSION: The extent and consistency of adverse effects documented in this study support the recommendation that concurrent administration of vincristine and itraconazole should be avoided.

Adolescent↗

PubMed2001

Timing and interpretation of tests for diagnosing perinatally acquired hepatitis C virus infection.

The diagnosis of hepatitis C virus (HCV) infection in children born to HCV-infected women is based on serologic assays and HCV RNA measurement by PCR. Interpretation of the results of these tests is hampered by uncertainty about the age distribution of loss of maternal antibody and the sensitivity and specificity of PCR at different ages. On the basis of findings from a recent vertical transmission study, we estimated the posttest probability of a child's being infected or uninfected under several test result scenarios. These estimates may assist clinicians in assessing the likelihood of infection in an individual child and in using the currently available assays cost effectively.

Age Factors↗

PubMed2001

Tissue-implant response following soft tissue implantation of poly-L-lysine coated UHMW-polyethylene into adult male rats.

It is well demonstrated in the literature that polyethylene materials used in orthopedic applications are highly compatible and non-immunogenic with host tissues. However, recent studies in our laboratory have demonstrated the need for further study of these devices in vivo to further elucidate the mechanisms involved in biocompatibility. The purpose of this investigation was to study the tissue-implant response resulting from the implantation of ultra high molecular weight polyethylene (PE) coated with poly-L-lysine at 90 days post-implantation. In this investigation, implants of PE coated with poly-L-lysine and saline were implanted into 8 adult male rats subcutaneously (S/C) and intraperitoneally (I/P). At 90 days post-implantation, the animals were euthanized; and the PE devices, the fibrous tissue, and vital organs were harvested. Evaluation of routinely stained sections (5 microns, Hematoxylin & Eosin) of the fibrous tissue capsule surrounding the PE implants revealed the following: 1) all the devices had fibrous connective tissue capsules of slightly varying degrees of thickness surrounding them present at the time of sacrifice, 2) the thickness of the fibrous tissue capsule was dependent on the site of implantation and type of coating, 3) the thickness of the fibrous tissue capsules around the subcutaneous devices differed markedly than those retrieved from the peritoneal cavity, and 4) there were statistically significant differences (T-test, p < 0.05) in the numbers and types of cellular components with respect to implantation site and type of coating.

Animals↗

PubMed2001

National guidelines for the active management of HIV in pregnancy.

The number of HIV positive women becoming pregnant in Ireland is increasing, with many pregnancies occurring in women from countries of high HIV prevalence. The management of such patients offers the challenge of reducing the risk of maternal-fetal transmission of HIV infection, avoiding fetal-infant toxicities, and maintaining future maternal antiretroviral options. Guidelines for the optimal management of HIV disease in pregnancy have been produced by a subgroup of the Irish Infection Society consisting of GenitoUrinary Medicine and Infectious Diseases Consultants. They are based on currently available international data and guidelines. The national guidelines offer a broad management outline for HIV positive pregnant patients. Ultimately, each patient is assessed individually by a multidisciplinary team, and a careful plan for antenatal, intrapartum, and postpartum care is determined.

Anti-HIV Agents↗

PubMed2000

Histamine H2 receptor mediated dual signaling: mapping of structural requirements using beta2 adrenergic chimeric receptors.

Previously we demonstrated that the histamine H2 receptor can activate both the adenylate cyclase and phosphoinositide/protein kinase (PKC) signaling pathways. Although dual coupling occurs via separate GTP-dependent mechanisms the structural components of the H2 receptor directing differential signaling have not been established. We explored this question by attempting to confer to the beta2-adrenergic receptor (betaAR), which is known to stimulate cAMP formation, the ability to activate PKC through the construction of beta2/H2 chimeric receptors. Intracytoplasmic domains of the human beta2 adrenergic receptor were substituted with the corresponding sequences of the human H2 receptor and stably expressed in HEK-293 cells. Binding of [(3)H]-CGP to chimeric wild type beta2 receptors was comparable. Substitution of the second intracellular loop (2i) of the betaAR led to a significant decrease in coupling to adenylate cyclase while leading to a 139.5 +/- 9.4% control increase in epinephrine mediated PKC activation. Introduction of the H2 receptor 3i also led to a decrease in betaAR mediated cAMP generation but provided the latter with the ability to stimulate PKC (182.2 +/- 8% of control). Concomitant expression of both 2i and 3i led to a substantial increase in epinephrine mediated PKC activation (201.8 +/- 10.5% of control). Addition of the carboxyl terminal tail did not facilitate stimulation of PKC. In summary, the third intracellular loop of the H2 receptor plays an essential role in activating PKC with maximal efficiency conferred by the second intracellular domain.

Adenylyl Cyclases↗

PubMed2000

Mother-to-child transmission of hepatitis C virus: evidence for preventable peripartum transmission.

BACKGROUND: Little information is available about the timing of mother-to-child transmission of hepatitis C virus (HCV), and no interventions to decrease transmission rates have been identified. We examined the effect of risk factors, including mode of delivery, on the vertical transmission rate. METHODS: Data from HCV-infected women and their infants from three hospitals in Ireland and from a British Paediatric Surveillance Unit study of infants born to HCV-infected mothers were used to estimate the vertical transmission rate and risk factors for transmission. We used a probabilistic model using methods that simultaneously estimated the time to HCV-antibody loss in uninfected infants and the diagnostic accuracy of PCR tests for HCV RNA. FINDINGS: 441 mother-child pairs from the UK (227) and Ireland (214) were included. 50% of uninfected children became HCV-antibody negative by 8 months and 95% by 13 months. The estimated specificity of PCR for HCV RNA was 97% (95% CI 96-99) and was unrelated to age; sensitivity was only 22% (7-46) in the first month but rose sharply to 97% (85-100) thereafter. The vertical transmission rate was 6.7% (4.1-10.2) overall, and 3.8 times higher in HIV coinfected (n=22) than in HIV-negative women after adjustment for other factors (p=0.06). No effect of breastfeeding on transmission was observed, although only 59 women breastfed. However, delivery by elective caesarean section before membrane rupture was associated with a lower transmission risk than vaginal or emergency caesarean-section delivery (odds ratio 0 [0-0.87], p=0.04, after adjustment for other factors). INTERPRETATION: The low sensitivity of HCV RNA soon after birth and the finding of a lower transmission rate after delivery by elective caesarean section suggest that HCV transmission occurs predominantly around the time of delivery. If the findings on elective caesarean section are confirmed in other studies, the case for antenatal HCV testing should be reconsidered.

Age Factors↗