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Biomedical subjects

A Waddell

Publications and source records attributed to A Waddell.

At least 19 recordsLinked to original sources
PubMed2006

Interventions for ear discharge associated with grommets (ventilation tubes).

BACKGROUND: The insertion of grommets (also known as ventilation or tympanostomy tubes) is one of the most common surgical procedures performed on children. Postoperative otorrhoea (discharge) is the most common complication with a reported incidence ranging from 10% to 50%. In the UK, many ENT surgeons treat with topical antibiotics/steroid combinations, but general practitioners, mainly through fears of ototoxicity, are unlikely to prescribe these and choose systemic broad-spectrum antibiotics. OBJECTIVES: 1. To identify the most effective non-surgical management of discharge from ears with grommets in place.2. To identify the risks of non-surgical management for this condition (e.g. ototoxicity), and to set benefits of treatment against these risks. SEARCH STRATEGY: We searched the Cochrane Ear, Nose and Throat Disorders Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 1, 2005), MEDLINE (1966 to 2005) and EMBASE (1974 to 2005). We also searched the CINAHL, AMED, LILACS, ISI WEB OF KNOWLEDGE, ISI PROCEEDINGS, mRCT, NNR, ZETOC, KOREAMED, CSA, MEDCARIB, INDMED and SAMED databases. The date of the last search was February 2005. SELECTION CRITERIA: Randomised controlled trials of adults or children, with any type of grommet and an ear with discharge were included. The trials compared treatment with placebo or one treatment with another. The primary outcome measure was the duration of the discharge. DATA COLLECTION AND ANALYSIS: The trials were selected independently according to the above criteria by the four reviewers. Differences in opinion over the inclusion of studies were resolved by discussion. The studies were graded using the CASP critical appraisal tool. Analyses were based on the presence of discharge seven days from the onset of treatment. MAIN RESULTS: There was very little good quality evidence. Four studies were included, all of them investigating different interventions and therefore a meta-analysis was not possible. Only one study demonstrated a significant difference. Oral amoxicillin clavulanate was compared to placebo in 79 patients. The odds of having a discharge persisting eight days after starting treatment was 0.19 (95% CI 0.07 to 0.49) . The number needed to treat to achieve that benefit is 2.5. Participants in both arms of this study also received daily aural toilet. The results will therefore not be applicable to most settings including primary care. No significant benefit was shown in the two studies investigating steroids (oral prednisolone with oral amoxicillin clavulanate and topical dexamethasone with topical ciprofloxacin ear drops), or the one study comparing an antibiotic-steroid combination (Otosporin(R)) drops versus spray (Otomize(R)) (although more patients preferred the spray form). AUTHORS' CONCLUSIONS: The authors of this review have been unable to identify the most effective intervention or to assess the associated risks. Research is urgently needed into the effectiveness of oral versus topical antibiotics in this group of patients. Clinicians considering antibiotic treatment need to balance any potential benefit against the risks of side effects and antibiotic resistance.

Adult↗
PubMed2004

The surgical arrest of post-tonsillectomy haemorrhage: hospital episode statistics.

INTRODUCTION: In the consent of patients for tonsillectomy, the risk of returning to theatre for control of postoperative bleeding may be determined from data provided on Hospital Episode Statistics (HES) provided by the Department of Health website. METHODS: HES data for England from 1998-2002 were used. The numbers of tonsillectomies and of surgical arrest of post-tonsillectomy haemorrhage were considered for children and adults. RESULTS: Of 220,497 tonsillectomies performed over the 4-year period, 1804 (0.82%) returned to theatre for control of bleeding. However, this was 3.87 times more likely in adults than children (P <0.0001). CONCLUSION: Adults are nearly four times more likely than children to require surgery for the arrest of post-tonsillectomy haemorrhage.

Adolescent↗
PubMed2003

Quality without tears--practical applications of quality assurance in biotechnology.

Expectations of society and funding bodies are increasing the application of quality management systems to research and development. Implementation of such systems needs to be performed sensibly to ensure that the creativity, which is at the core of the research process, can still thrive whilst increasing the visible reliability of outputs. This paper explores the application of quality principles to research and development and provide practical advice on their application.

Biotechnology↗
PubMed2001

Cholesteatoma causing facial nerve transection.

Cholesteatoma is a well recognized cause of a facial nerve palsy. The usual mechanism for this complication is direct pressure on the nerve. We present a case in which the facial nerve has been transected by cholesteatoma and discuss the possible causes.

Aged↗
PubMed2000

Thyroglossal duct remnants.

Thyroglossal duct remnants presenting as a lump in the neck are usually called thyroglossal cysts. Meticulous dissection of the cyst and duct, along with the body of the hyoid bone (Sistrunk's operation) is necessary to avoid recurrence. The authors have reviewed the histology of 61 consecutive specimens diagnosed preoperatively as thyroglossal cysts and have found that a true cyst exists in only 46 per cent of cases.

Adolescent↗
PubMed1997

The Great Ormond Street protocol for ward decannulation of children with tracheostomy: increasing safety and decreasing cost.

Ward decannulation is the eventual endpoint for the majority of the 40 children managed by tracheostomy at Great Ormond Street Hospital each year. Our previous protocol dictated a 10 day stay in hospital for the 25 children decannulated annually. The aim of this retrospective study was to determine the minimum safe duration for this inpatient stay. In addition, we hoped to identify any factors which might distinguish potentially successful candidates from those likely to fail decannulation. Of 104 patients decannulated between January 1991 and January 1996, complete nursing and medical records were retrieved for 84 children. These notes were retrospectively reviewed and in this group of patients there were 101 attempted decannulations. Information about the initial pathology, interim course and details of the decannulation were collected. Summary statistics were generated. There was no relation between initial pathology or duration of tracheostomy and eventual success or failure of decannulation. Observations by the nursing staff of restlessness, anxiety and recession appeared more frequently in children who eventually failed decannulation. All failures occurred within 48 h of the 24 h trial of tracheostomy blocking. Our results suggest that a safe decannulation protocol can allow discharge after day five.

Adolescent↗
PubMed1996

Detection of herpesviridae in postmortem multiple sclerosis brain tissue and controls by polymerase chain reaction.

OBJECTIVE: To test for the presence of herpesviruses in postmortem brain samples from multiple sclerosis patients and controls using polymerase chain reaction. BACKGROUND: Herpes simplex virus, varicella-zoster virus, Epstein-Barr virus, cytomegalovirus, and human herpesvirus-6 are common viruses capable of persistence and latency. All have been detected in the CNS. METHODS: Active and inactive plaque tissue, unaffected white matter (WM) and gray matter (GM) from MS cases, and WM and GM controls (Alzheimer's disease, Parkinson's disease and non-neurological disease) were screened for the herpesvirus by PCR. RESULTS: (1) 37% of the MS cases were positive for herpes simplex virus (HSV). Twenty-eight percent of controls cases were positive for HSV. Forty-one percent of active plaques were positive for HSV in contrast to only 20% of inactive plaques (Sanders et al, 1996). (2) 57% of the MS cases and 43% of the control cases were positive for HHV-6. Thirty-two percent of the active plaques contained HHV-6 compared to 17% of inactive plaques. (3) 43% of the MS cases and 32% of the control cases were positive for VZV. Fourteen percent of the active plaques and 10% of the inactive plaques were positive for VZV. (4) 27% of MS cases and 38% of control cases were positive for EBV. Five percent of the active plaques were positive for EBV and 10% of the inactive plaques were positive. (5) 16% of the MS cases and 22% of the controls were positive for CMV. Nine percent of the active plaques and 10% of the inactive plaques were positive. We also compared MS WM and GM with controls and found no significant difference. CONCLUSIONS: HSV, HHV-6, and VZV were present in a greater frequency of MS cases compared to controls; however, no statistical differences were noted. The presence of herpesvirus in all tissue makes an etiologic association to MS uncertain. Cellular localization of virus and its relationship to pathology and latency may reveal an association.

Adult↗
PubMed1986

Antibody-selected variation and reversion in Sindbis virus neutralization epitopes.

Sindbis virus variants evidencing a complex and bidirectional tendency toward spontaneous antigenic change were isolated and characterized. Variants were selected on the basis of their escape from neutralization by individual monoclonal antibodies to either of the two envelope glycoproteins, E2 and E1. Multisite variants, including one altered in three neutralization sites, were obtained by selecting mutants consecutively in the presence of different neutralizing monoclonal antibodies. Two phenotypic revertants, each of which reacquired prototype antigenicity, were back-selected on the basis of their reactivity with a neutralizing monoclonal antibody. An incidental oligonucleotide marker distinguished these and the variant from which they arose from parental Sindbis virus and other mutants, thereby confirming that the revertants were true progeny of the antigenic variant. Prototype Sindbis virus and variants derived from it were compared on the basis of their reactivities with each of a panel of monoclonal antibodies; patterns revealed a minimum of five independently mutable Sindbis virus neutralization epitopes, segregating as three antigenic sites (two E2 and one E1).

Animals↗
PubMed1983

Interferonlike factors from antigen- and mitogen-stimulated human leukocytes with antirickettsial and cytolytic actions on Rickettsia prowazekii. Infected human endothelial cells, fibroblasts, and macrophages.

Unique features of the primary site of rickettsial replication in typhus fevers, i.e., within the endothelial cells of small blood vessels in tissues, suggest that effector mechanisms, other than those dependent on phagocytosis by activated macrophages with enhanced microbicidal properties, most likely are necessary to explain the cell-mediated immune control of intracellular rickettsial replication in these sites. Theoretically, such mechanisms might involve contact between infected endothelial cells and activated T lymphocyte subpopulations or macrophages or immunologically induced soluble factors or lymphokines. Support for the existence of at least one of these alternative effector mechanisms is presented here for Rickettsia prowazekii. Cultures of human blood leukocytes, upon immunologically specific stimulation with R. prowazekii antigen or nonspecific stimulation with the mitogen phytohemagglutinin, produce soluble factor(s) in the supernatant fluid which, in culture, have (a) an intracellular antirickettsial action on R. prowazekii-infected human endothelial cells, fibroblasts, and macrophages, and (b) a specific cytolytic action on R. prowazekii-infected, but not uninfected bystander, human fibroblasts. Neither action is demonstrable in R. prowazekii-infected chicken embryo fibroblasts. The factor(s) has no direct antimicrobial action on extracellular rickettsiae and is inactivated by heating at 56 degree C for 1 h or by acid treatment at pH 2. Expression of the antirickettsial action requires new host cell messenger transcription and protein synthesis, whereas the cytolytic action does not. The circumstances of production and action and the properties of the factor(s) responsible for the intracellular antirickettsial, and perhaps also the cytolytic action are consistent with those of immune interferon (IFN-gamma).

Animals↗
PubMed1982

Penicillin-induced unstable intracellular formation of spheroplasts by rickettsiae.

Penicillin G (greater than or equal to 20 micrograms/ml) is rapidly rickettsiacidal for intracellular Rickettsia prowazekii. Light and electron microscopic examinations revealed that penicillin G in culture medium induced a predictable transformation into typical enlarging spheroplasts deficient in the internal, putative peptidoglycan layer of the outer membrane. Under certain conditions, spheroplasts ruptured to discharge contents into host cell cytoplasm and to leave empty shells of defective outer membrane and diffuse amorphous intracytoplasmic antigen. Host cell destruction often accompanied spheroplast rupture. Penicillin G (100 micrograms/ml) caused similar spheroplast formation by Rickettsia rickettsii, but 1,000 micrograms/ml caused neither growth inhibition nor spheroplast formation in Rickettsia tsutsugamushi. The clinical and epidemiological significance of a practical rickettsiacidal drug for the treatment of louse-borne typhus fever is discussed. Practical pharmacologic considerations preclude the use of penicillin for the treatment of typhus or spotted fever.

Animals↗
PubMed1981

Some characteristics of heavy and light bands of Rickettsia prowazekii on Renografin gradients.

Suspensions of partially purified Rickettsia prowazekii yielded two bands of organisms when centrifuged to equilibrium in Renografin density gradients. Rickettsiae from the lower, heavy band were defective in their infective and metabolic activities, as compared to organisms from the light band. The greater density in Renografin of heavy-banding organisms was due to their lack of permeability barrier to it, as evidenced by the absence of plasmolysis in hypertonic Renografin. In contrast, light-banding rickettsiae were able to exclude Renografin, since they were plasmolyzed in it. The proportion of heavy-banding organisms in a rickettsial suspension was influenced by the growth phase they were in when harvested from infected yolk sacs, as well as by the conditions and media to which they subsequently were exposed. We have concluded that these defective forms arise from the degeneration of light-banding rickettsiae. This separation of two functional classes of rickettsiae in Renografin density gradients has been exploited (i) to increase the uniformity of the suspensions by removing many noninfectious particles and (ii) to determine rapidly the integrity of certain properties of the cytoplasmic membrane of organisms exposed to a variety of conditions.

Cell Membrane↗
PubMed1980

In vitro studies of Rickettsia-host cell interactions: ultrastructural study of Rickettsia prowazekii-infected chicken embryo fibroblasts.

Secondary chicken embryo fibroblasts infected in suspension with the Breinl strain of Rickettsia prowazekii and grown in monolayer culture were examined by both transmission and scanning electron microscopy at specific intervals after infection to study the effects of prolonged intracellular growth on the fine structure of the host cell and the rickettsiae. Cytopathological changes in the infected host cells were not apparent until late in the intracellular growth cycle when the cells began to rupture as a result of a large rickettsial burden. The only recognizable changes in heavily infected cells before lysis were the condensation of the intercristal matrix of some mitochondria and the apparent dissociation of ribosomes from the rough-surfaced endoplasmic reticulum. Although the effects of intracellular growth of rickettsiae on the fine structure of the host cell were rather unremarkable when compared with those imposed by Rickettsia rickettsii in a similar cell system, noticeable morphological changes in the rickettsiae were recognized during the intracellular growth cycle. These changes first became apparent about 40 h postinfection and consisted primarily of an increased electron density of the rickettsiae, the appearance of numerous vacuoles in the rickettsial cytoplasm, and a slight reduction in size of the rickettsiae. Changes of this nature may reflect transitional phases of growth characteristically seen in free-living bacterial cell systems.

Animals↗
PubMed1970

DNA and gene therapy: uncoating of polyoma pseudovirus in mouse embryo cells.

Pseudovirions (host DNA fragments encapsidated by polyoma virus-coat protein) and polyoma virions are produced after infection of primary mouse embryo cells with polyoma virus. Purified pseudovirions are adsorbed to, and uncoated by, mouse embryo cells. The evidence for this uncoating is based on the conversion by pancreatic DNase of the uncoated pseudovirus DNA from an acid-insoluble to an acid-soluble form. The implications of these experiments to the eventual use of DNA for gene therapy are discussed.

Animals↗