PubMed Health⌕ Search

Biomedical subjects

F O'Brien

Publications and source records attributed to F O'Brien.

At least 19 recordsLinked to original sources

Randomized study of once-weekly interferon beta-1la therapy in relapsing multiple sclerosis: three-year data from the OWIMS study.

BACKGROUND: Once weekly interferon beta-1a for multiple sclerosis (OWIMS) demonstrated modest, but significant, magnetic resonance imaging (MRI) benefit of once-weekly (qw) interferon (IFN) beta-1a at 48 weeks, but no significant effect on relapses. OBJECTIVE: An OWIMS extension permitted assessment of longer-term efficacy/safety of qw IFN beta-1a in relapsing-remitting multiple sclerosis (RRMS). METHODS: Placebo patients were rerandomized to IFN beta-1a, 22 or 44 mcg qw, for two additional 48-week intervals. Primary outcome was MRI lesion activity. Relapse rate and other MRI measures were secondary outcomes. RESULTS: After three years, median (mean) T2 lesion count/patient/scan was 1.3 (2.6) for 44 mcg, 1.7 (3.3) for 22 mcg, 1.7 (3.4) for placebo/22 mcg, 2.0 (3.6) for placebo/44 mcg (all differences not significant). Annualized relapse rates were lowest for 44 mcg (0.77) versus other groups (0.83-0.86, not significant). Persistent neutralizing antibodies did not affect relapse rates, but MRI active lesions were increased in antibody-positive patients receiving 44 mcg compared to antibody negative patients. CONCLUSIONS: In RRMS, once weekly IFN beta-1a, particularly 44 mcg, can induce a significant MRI, but not relapse, effect, compared with placebo. No significant dose effect was seen. In contrast to the significant effect observed with three-times-weekly dosing of subcutaneous IFN beta-1a compared with placebo, this study confirms the lack of meaningful clinical benefit with once-weekly dosing.

Adjuvants, Immunologic↗

The neurodevelopmental progress of infants less than 33 weeks into adolescence.

BACKGROUND: Several studies have shown an increased incidence of neurodevelopmental impairment in very preterm survivors at school age compared with controls. AIM: To compare findings in the same cohort at 8 years and 15 years. METHODS: A total of 151 of the 224 eligible infants born before 33 weeks of gestation from 1979 to 1982, and who were living in the UK, were assessed at 8 and 15 years. Items common to both assessments were compared to evaluate changes in neurodevelopmental function. The assessment included a structured neurological examination, psychometric tests using the WISC-R (in subjects born in 1981-82), a test of visuomotor integration (Beery), and a school questionnaire. RESULTS: There was a significant increase in the proportion of subjects classified as impaired with disability from 11% at 8 to 22% at 14-15 years of age. The proportion of subjects classified as impaired without disability increased from 16% at 8 to 26% at 14-15 years of age. Full scale IQ decreased from 104 to 95 from childhood to adolescence, and more adolescents (24%) were requiring extra educational provision than they had at the age of 8 years (15%). CONCLUSION: Results indicate that between the ages of 8 and 15 years in this cohort of very preterm survivors there is an apparent deterioration in neurodevelopmental outcome category, cognitive function, and extra educational support. It is not clear whether this represents a genuine deterioration in neurocognitive function or whether it represents the expression of pre-existing cerebral pathology in an increasingly complex environment.

Adolescent↗

Emergence of vancomycin-resistant Enterococcus faecium at a tertiary care hospital in Karachi, Pakistan.

Vancomycin-resistant enterococcus (VRE) has not been reported previously in Pakistan. This is the first report where in vancomycin-resistant Enterococcus faecium was isolated from the clinical specimens of six patients admitted to the intensive care unit (ICU) and neonatal intensive care unit (NICU) of the Aga Khan University Hospital, Karachi. To identify the extent of the outbreak, rectal swabs were obtained from all the patients admitted to the ICU and NICU at that time. A total of 10 strains of vancomycin-resistant Enterococcus faecium were isolated. All the strains showed high-level resistance to both glycopeptides (vancomycin and teicoplanin) with a vancomycin minimum inhibitory concentration greater than 256 mg/L. All isolates had the vanA gene detected by polymerase chain reaction. The contour-clamped homogeneous electric field (CHEF) pattern demonstrated that all but one of the isolates were of a single clone, suggesting that they were derived from common source. Use of vancomycin and prolonged hospitalization were common features in all cases investigated.

Adult↗

Recruitment of CD1a+ Langerhans cells to the nasal mucosa in seasonal allergic rhinitis and effects of topical corticosteroid therapy.

BACKGROUND: Local antigen presentation may be necessary for both primary and recall T-cell responses to grass pollen in hay fever patients. We examined the effect of seasonal allergen exposure on nasal mucosal antigen-presenting cell (APC) populations and the effects of topical corticosteroid therapy. METHODS: Nasal biopsies were collected from 46 grass pollen-sensitive seasonal rhinitis patients before the grass-pollen season. A second biopsy was collected during the pollen season, when patients had received 6 weeks' treatment with either fluticasone propionate (200 microg, twice daily) or placebo. Cell populations in biopsy sections were quantified by immunocytochemistry. RESULTS: Significant increases in submucosal and epithelial CD1a+ Langerhans cells, but not CD68 + macrophages or CD20 + B cells, were observed during the pollen season. Seasonal increases in CD1a+ Langerhans cells were inhibited by corticosteroid therapy. CONCLUSIONS: Recruitment of CD1a+ Langerhans cells to the nasal mucosa during natural seasonal allergen exposure may contribute to local T cell responses. Topical corticosteroids may act, at least in part, by inhibiting effective allergen presentation to T cells through inhibition of recruitment of Langerhans cells to the nasal mucosa.

Administration, Topical↗

Grass pollen immunotherapy: symptomatic improvement correlates with reductions in eosinophils and IL-5 mRNA expression in the nasal mucosa during the pollen season.

BACKGROUND: Tissue eosinophilia and infiltration by T(H)2-type T cells are characteristic features of allergic rhinitis both after allergen challenge and during natural allergen exposure. Specific immunotherapy inhibits allergen-induced nasal eosinophilia. OBJECTIVES: We sought to assess, in the context of a randomized trial, the relationships between symptomatic improvement after immunotherapy and eosinophil numbers and IL-5 expression in the nasal mucosa during the pollen season. METHODS: Nasal biopsy specimens were taken from 37 adults with severe summer hay fever at baseline (out of season) and at peak season after 2 years of treatment with a depot grass pollen extract or placebo. Biopsy specimens were processed for immunohistochemistry by using mAbs against eosinophils (EG2), T cells (CD3), and IL-2 receptor-positive cells (CD25), as well as for in situ hybridization by using a sulfur 35-labeled antisense riboprobe directed against IL-5. RESULTS: Immunotherapy significantly reduced symptoms (49%, P =.01) and medication requirements (80%, P =.007) compared with placebo. There was a 400% increase (P =.004) in eosinophils during the pollen season in placebo-treated patients, which was inhibited in the immunotherapy group (20% increase, P =.04 between groups). Seasonal increases were also observed for CD25(+) cells (P =.002), CD3(+) cells (P =.02), and IL-5 mRNA-expressing cells (P =.03) in the placebo group but not in the immunotherapy group. A significant correlation was observed between eosinophils and IL-5 expression (r = 0.5, P <.05). Both eosinophils (r = 0.6, P <.02) and IL-5 (r = 0.6, P <.02) correlated with symptoms after immunotherapy. CONCLUSION: Improvement in symptoms after grass pollen immunotherapy may result, at least in part, from inhibition of IL-5-dependent tissue eosinophilia during the pollen season.

Biopsy↗

Cytokine expression during allergen-induced late nasal responses: IL-4 and IL-5 mRNA is expressed early (at 6 h) predominantly by eosinophils.

The production of TH2-type cytokines [interleukin-4 (IL-4) and IL-5] and tissue eosinophilia are characteristic features of allergic diseases. It was previously reported that at 24 h after allergen provocation, CD3+ T-lymphocytes were the principal cell source of IL-4 and IL-5 mRNA transcripts in both atopic asthma and rhinitis. To investigate whether IL-4 and IL-5 mRNA are expressed earlier during late nasal responses and if so, which cell(s) are responsible. Nasal biopsies were obtained at 6 h after nasal allergen challenge and following a control challenge with the allergen diluent. Sections were immunostained for T-lymphocytes (CD3+, CD4+) and eosinophils (EG2+). In situ hybridization was used to detect the number of cells expressing messenger RNA (mRNA) for IL-4 and IL-5. In patients with allergic rhinitis, eosinophils (EG2+ cells P = 0. 006) but not T- cells (CD3+ cells) increased in the nasal mucosa at 6 h after allergen challenge. The number of cells expressing IL-4 mRNA (P = 0.01) and IL-5 mRNA (P = 0.05) also increased at 6 h. Co-localization studies showed that 76% of IL-4 mRNA+ cells and 77% of IL-5 mRNA+ cells were eosinophils, whereas at this time point, T-cells and mast cells accounted for </=5% of mRNA expression; the identity of the remaining 20% of IL-4 and IL-5 mRNA+ cells was not determined. By use of immunohistology, cytokine protein expression at 6 h was confirmed for IL-4 but not for IL-5. No increases in T-cells, eosinophils or cytokine expression were detected in non-atopic subjects. Eosinophils represent an early source of IL-4 which may contribute to TH2-type responses during late nasal responses and ongoing allergic rhinitis.

Adult↗

The impact of adhesions on hospital readmissions over ten years after 8849 open gynaecological operations: an assessment from the Surgical and Clinical Adhesions Research Study.

OBJECTIVE: To investigate the epidemiology of, and the clinical burden related to, adhesions following gynaecological surgery. POPULATION: The Scottish National Health Service Medical Record Linkage Database was used to define a cohort of 8849 women undergoing open gynaecological surgery in 1986. METHODS: All readmissions for potential adhesion related disease in the subsequent 10 years were reviewed. MAIN OUTCOME MEASURES: Readmissions and the degree of adhesion involvement gave an indication of clinical burden and workload. The rate of readmission following the initial surgery determined the relative risk of disease related to adhesions. RESULTS: Two hundred and forty-five (4.5%) of 5433 readmissions following open gynaecological surgery were directly related to adhesions. 34.5% of patients were readmitted, on average 1.9 times, for a problem potentially related to adhesions or for further intra-abdominal surgery that could be complicated by adhesions. Readmissions related to adhesions continued throughout the 10 year period of the study. The overall rate of readmission was 64.0/100 initial operations. For readmissions directly related to adhesions, the rate was 2.9/100 initial operations. Operations on the ovary had the highest rate directly related to adhesions (7.5/100 initial operations), with an overall rate of readmission of 106.4/100 initial operations. CONCLUSIONS: Despite the conservative approach taken in this study, the clinical burden, workload and relative risk of readmissions related to adhesions following open gynaecological surgery was considerable. Post-operative adhesions have important consequences for patients, surgeons and the healthcare system. These results emphasise the need for more effective strategies to prevent adhesions.

Cohort Studies↗

Diagnosis of skin disease by nondermatologists.

OBJECTIVE: To determine how often primary care physicians diagnose and treat skin disease and to compare their experience with that of dermatologists. STUDY DESIGN: Retrospective review of National Ambulatory Medical Care Survey data. METHODS: We reviewed data from the 1990-1994 National Ambulatory Medical Care Survey on outpatient visits to physicians for both dermatologic and nondermatologic disorders. RESULTS: Dermatitis is the most common dermatologic problem diagnosed by internists, family physicians, and pediatricians and is the 35th, 17th, and 15th most common diagnosis made by these providers, respectively. Dermatologists had 728 and 352 office visits per year for acne and contact dermatitis, respectively, whereas internists averaged 3 and 9 visits, family physicians averaged 8 and 27 visits, and pediatricians averaged 8 and 37 visits. Overall, dermatologists spent 930 outpatient hours per year with patients with dermatologic conditions, compared with 21, 53, and 56 hours per year for internists, family physicians, and pediatricians. CONCLUSIONS: Although most visits for skin disease are managed by primary care physicians, these physicians treat few cases of individual skin conditions. The different levels of experience between dermatologists and nondermatologists may affect the quality of dermatologic care and may explain in part the greater expertise dermatologists have in diagnosing and treating skin disease. This should be considered in decisions about the delivery of dermatologic healthcare services and in planning educational programs designed to improve dermatologic care.

Ambulatory Care↗

Long-term clinical efficacy of grass-pollen immunotherapy.

BACKGROUND: Pollen immunotherapy is effective in selected patients with IgE-mediated seasonal allergic rhinitis, although it is questionable whether there is long-term benefit after the discontinuation of treatment. METHODS: We conducted a randomized, double-blind, placebo-controlled trial of the discontinuation of immunotherapy for grass-pollen allergy in patients in whom three to four years of this treatment had previously been shown to be effective. During the three years of this trial, primary outcome measures were scores for seasonal symptoms and the use of rescue medication. Objective measures included the immediate conjunctival response and the immediate and late skin responses to allergen challenge. Cutaneous-biopsy specimens obtained 24 hours after intradermal allergen challenge were examined for T-cell infiltration and the presence of cytokine-producing T helper cells (TH2 cells) (as evidenced by the presence of interleukin-4 messenger RNA). A matched group of patients with hay fever who had not received immunotherapy was followed as a control for the natural course of the disease. RESULTS: Scores for seasonal symptoms and the use of rescue antiallergic medication, which included short courses of prednisolone, remained low after the discontinuation of immunotherapy, and there was no significant difference between patients who continued immunotherapy and those who discontinued it. Symptom scores in both treatment groups (median areas under the curve in 1995, 921 for continuation of immunotherapy and 504 for discontinuation of immunotherapy; P=0.60) were markedly lower than those in the group that had not received immunotherapy (median value in 1995, 2863). Although there was a tendency for immediate sensitivity to allergen to return late after discontinuation, there was a sustained reduction in the late skin response and associated CD3+ T-cell infiltration and interleukin-4 messenger RNA expression. CONCLUSIONS: Immunotherapy for grass-pollen allergy for three to four years induces prolonged clinical remission accompanied by a persistent alteration in immunologic reactivity.

Adult↗

Adhesion-related hospital readmissions after abdominal and pelvic surgery: a retrospective cohort study.

BACKGROUND: Adhesions after abdominal and pelvic surgery are important complications, although their basic epidemiology is unclear. We investigated the frequency of such complications in the general population to provide a basis for the targeting and assessment of new adhesion-prevention measures. METHODS: We used validated data from the Scottish National Health Service medical record linkage database to identify patients undergoing open abdominal or pelvic surgery in 1986, who had no record of such surgery in the preceding 5 years. Patients were followed up for 10 years and subsequent readmissions were reviewed and outcomes classified by the degree of adhesion. We also assessed the rate of adhesion-related admissions in 1994 for the population of 5 million people. FINDINGS: 1209 (5.7%) of all readmissions (21,347) were classified as being directly related to adhesions, with 1169 (3.8%) managed operatively. Overall, 34.6% of the 29,790 patients who underwent open abdominal or pelvic surgery in 1986 were readmitted a mean of 2.1 times over 10 years for a disorder directly or possibly related to adhesions, or for abdominal or pelvic surgery that could be potentially complicated by adhesions. 22.1% of all outcome readmissions occurred in the first year after initial surgery, but readmissions continued steadily throughout the 10-year period. In 1994, 4199 admissions were directly related to adhesions. INTERPRETATION: Postoperative adhesions have important consequences to patients, surgeons, and the health system. Surgical procedures with a high risk of adhesion-related complications need to be identified and adhesion prevention carefully assessed.

Abdomen↗

Compression data on bovine bone confirms that a "stressed volume" principle explains the variability of fatigue strength results.

The literature contains many measurements of the fatigue properties of compact bone, but these experimental results have been difficult to interpret and use due to a large amount of apparent scatter: variation in the number of cycles to failure for a given cyclic stress or strain range. Recently Taylor (1998a, Journal of Orthopaedic Research, 16, 163-169) showed that much of this scatter could be explained using a statistical model which took into account specimen size, or more specifically stressed volume. The present paper describes an attempt to test this model by using it to predict some new data, for bovine bone tested in compressive loading at room temperature at physiological loading rates. Twenty specimens were tested at the same applied load range (100 MPa). The theory was able to predict the mean behaviour of the specimens very well, with an accuracy (expressed in terms of stress) of 2%. It was also able to predict the degree of scatter (i.e. the variation of Nf), which was shown to be similar to that measured by other workers.

Animals↗

Cellular infiltration and cytokine mRNA expression in perennial allergic rhinitis.

BACKGROUND: Allergen challenge in allergic rhinitis patients leads to local eosinophilia and Th2-type cytokine expression. Natural exposure to grass pollen is additionally characterized by epithelial mast-cell infiltration. We hypothesized that perennial allergic rhinitis is also associated with T-cell and eosinophil infiltration of the nasal mucosa, local Th2-type cytokine expression, and increased numbers of nasal epithelial mast cells. METHODS: Nasal biopsies from perennial allergic rhinitis patients and controls were analysed by immunocytochemistry for different cell populations and in situ hybridization for cytokine mRNA-expressing cells. RESULTS: Perennial allergic rhinitis was associated with increased numbers of submucosal CD3+ T cells (P=0.05), EG2+ activated eosinophils (P=0.01), and CD68+ macrophages (P=0.01) compared to controls. Epithelial, but not submucosal, tryptase-positive mast cells were also elevated in rhinitics compared to controls (P=0.01). The numbers of cells expressing interleukin (IL)-5 were higher (P=0.01) and the numbers of cells expressing IL-2 were lower (P=0.04) in rhinitic patients than controls. There were no significant differences for either IL-4 or interferon-gamma between the groups. CONCLUSIONS: Perennial allergic rhinitis is characterized by mast-cell migration into the epithelium; submucosal infiltration by T cells, eosinophils, and macrophages; and an imbalance in local T-cell cytokine production in favour of enhanced IL-5 and reduced IL-2 expression.

Adult↗

Emergence and epidemiology of vancomycin-resistant enterococci in Australia.

Enterococci with acquired resistance to vancomycin and other glycopeptides (VRE) have emerged and spread rapidly through Europe and the United States since 1988. The first isolate of VRE in Australia occurred in 1994. Only one case was noted in 1995. Since March 1996 there has been a steady increase in the number of reports of VRE throughout the country. To August 1998 there have been 69 documented strains or clusters of strains detected in patients with documented infection, and about 3 times as many strains have been detected through screening procedures of contacts or in risk groups. 19% of strains whose source was known were blood isolates, while 34% came from urine and 47% came from other specimens. The strains have been found in 26 institutions in 10 widely separated cities or regions of the country (in 6/8 states or territories), without any obvious temporal associations in their appearance. All strains appear to have arisen locally except for one strain imported from the United Kingdom. Furthermore there was no direct evidence of interhospital transfer of strains. All clinical strains were examined by PCR to confirm species and to test for the presence of known vancomycin-resistance genes. Of the 69 strains, 42 were vanB E. faecium, 12 were vanA E. faecium, 9 were vanB E. faecalis, 3 were vanA E. faecalis. Three were negative for vanA, vanB, vanC1, vanC2/C3 and vanD. PGFE profiles on 38 strains have revealed at least 8 types of vanB E. faecium, 6 of vanA E. faecium, 4 of vanB E. faecalis and 2 of vanA E. faecalis. Isolates containing vanA always had different profiles from those containing vanB. Clinical clustering was confirmed by PFGE, and supported by extended antibiogram. 14 of 15 E. faecalis were ampicillin susceptible compared to only 2 of 54 E. faecium. One E. faecalis strain was beta-lactamase positive. The epidemiology of VRE in Australia appears to be different from that of Europe or the United States, since vanB E. faecium predominates and strains have appeared in diverse locations independently and are highly polyclonal.

Anti-Bacterial Agents↗

Assessment of resolution and intercenter reproducibility of results of genotyping Staphylococcus aureus by pulsed-field gel electrophoresis of SmaI macrorestriction fragments: a multicenter study.

Twenty well-characterized isolates of methicillin-resistant Staphylococcus aureus were used to study the optimal resolution and interlaboratory reproducibility of pulsed-field gel electrophoresis (PFGE) of DNA macrorestriction fragments. Five identical isolates (one PFGE type), 5 isolates that produced related PFGE subtypes, and 10 isolates with unique PFGE patterns were analyzed blindly in 12 different laboratories by in-house protocols. In several laboratories a standardized PFGE protocol with a commercial kit was applied successfully as well. Eight of the centers correctly identified the genetic homogeneity of the identical isolates by both the in-house and standard protocols. Four of 12 laboratories failed to produce interpretable data by the standardized protocol, due to technical problems (primarily plug preparation). With the five related isolates, five of eight participants identified the same subtype interrelationships with both in-house and standard protocols. However, two participants identified multiple strain types in this group or classified some of the isolates as unrelated isolates rather than as subtypes. The remaining laboratory failed to distinguish differences between some of the related isolates by utilizing both the in-house and standardized protocols. There were large differences in the relative genome lengths of the isolates as calculated on the basis of the gel pictures. By visual inspection, the numbers of restriction fragments and overall banding pattern similarity in the three groups of isolates showed interlaboratory concordance, but centralized computer analysis of data from four laboratories yielded percent similarity values of only 85% for the group of identical isolates. The differences between the data sets obtained with in-house and standardized protocols could be the experimental parameters which differed with respect to the brand of equipment used, imaging software, running time (20 to 48 h), and pulsing conditions. In conclusion, it appears that the standardization of PFGE depends on controlling a variety of experimental intricacies, as is the case with other bacterial typing procedures.

Bacterial Typing Techniques↗

Increases in CD4+ T lymphocytes, macrophages, neutrophils and interleukin 8 positive cells in the airways of patients with bronchiectasis.

BACKGROUND: Bronchiectasis is a chronic suppurative lung disease characterised by irreversible dilation of the bronchi and persistent purulent sputum. The immunopathology of the disease was studied using a quantitative immunostaining technique with particular reference to T lymphocytes, macrophages, and granulocytes. METHODS: Bronchial mucosal biopsy specimens were obtained by fibreoptic bronchoscopy from 12 patients with bronchiectasis (six receiving inhaled steroids) and 11 normal healthy controls. Immunostaining (APAAP method) was performed on frozen cryostat sections with a panel of monoclonal antibodies to total leucocytes (CD45), T lymphocyte phenotypic markers (CD3, CD4, CD8), macrophages (CD68), eosinophils (EG2), and neutrophils (elastase). RESULTS: There was a mononuclear cell infiltrate in both patients with bronchiectasis and normal controls, but an overall increase in total leucocyte cell numbers (CD45+ cells) was identified in those with bronchiectasis (median values 422 cells/mm2 versus 113 cells/mm2 in control tissue, p < 0.001). Intense infiltration of CD3+ T lymphocytes was observed compared with healthy controls (292 cells/mm2 and 40 cells/mm2, respectively, p < 0.001). This comprised predominantly CD4+ T cells (118 cells/mm2) rather than CD8+ T cells (47 cells/mm2). CD3+ cells counts were reduced in those subjects on inhaled steroids compared with those not receiving inhaled steroids (197 cells/mm2 versus 369 cells/mm2, p < 0.05), as were CD4+ cell counts (82 cells/mm2 versus 190 cells/mm2, p < 0.05). Neutrophil and macrophage cell numbers were also increased in patients with bronchiectasis (114 cells/mm2 and 213 cells/mm2, respectively) compared with controls (41 neutrophils/mm2 and 40 macrophages/mm2). EG2+ (activated) eosinophil numbers were much lower than T cells, macrophages, and neutrophils in patients with bronchiectasis but were increased compared with controls (36 cells/mm2 versus 0 cells/mm2, p < 0.001). In view of the markedly increased neutrophil counts in patients with bronchiectasis, biopsy specimens were immunostained for interleukin 8 (IL-8) which was highly significantly increased compared with controls (47 cells/mm2 versus 15 cells/mm2, p < 0.01). IL-8+ cells were less prominent in steroid treated patients than in patients not receiving treatment (30 cells/mm2 versus 60 cells/mm2, p < 0.05). A further characteristic of bronchiectasis was mucous gland hypertrophy. Gland area comprised up to 40% of the tissue in some bronchiectasis sections while no hypertrophy was noted in control biopsy specimens (p < 0.05). CONCLUSION: Airway inflammation in bronchiectasis is characterised by tissue neutrophilia, a mononuclear cell infiltrate composed mainly of CD4+ T cells and CD68+ macrophages, and increased IL-8 expression. Inhaled corticosteroid treatment in patients with bronchiectasis is associated with a less marked infiltration by T cells and IL-8+ cells within the bronchial mucosa, although this finding requires confirmation in a prospective placebo controlled trial.

Adult↗