Biomedical subjects
B Scheer
Publications and source records attributed to B Scheer.
Conscious sedation.
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Analysis of paediatric dental care provided under general anaesthesia and levels of dental disease in two hospitals.
OBJECTIVE: To compare the level of dental disease and the pattern of dental treatment under controlled airway general anaesthesia for ASA I and II children and ASA III and IV children in two hospitals. DESIGN: Prospective analysis. SETTING: Hospital and postgraduate dental teaching institution, UK 1996 - 2000. SUBJECTS AND METHODS: During a four-year period (1996-2000), data were collected on children aged 1 to 16 years who were admitted for treatment of dental caries under general anaesthesia. Outcome measures Levels of dental disease (dmft/DMFT), treatment provided. RESULTS: A total of 515 ASA I and II and 430 ASA III and IV children were treated. The dmft and DMFT values of the ASA I and II children were significantly higher than those of the ASA III and IV children (p = 0.03). A significantly greater number of restorations and fissure sealants were carried out for permanent teeth in ASA III and IV children (p < 0.001). The number of extractions for both primary and permanent teeth was significantly greater in the ASA I and II group (p < 0.05). CONCLUSIONS: The ASA III and IV children had significantly lower levels of dental caries than the ASA I and II children and received a higher level of preventive and restorative care.
Morbidity following dental treatment of children under intubation general anaesthesia in a day-stay unit.
OBJECTIVES: To determine which variables were best related to the overall morbidity of a child undergoing dental general anaesthetic (GA) and then to use these variables to determine those factors that might influence the extent and severity of morbidity experienced by healthy children following dental GA. SAMPLE AND METHODS: Data were collected on anxiety, pain and morbidity, GA procedure and dental procedure from 121 children attending a day stay GA unit for dental treatment. Patients were interviewed preoperatively, postoperatively before discharge then four further times over the next 148 h. Data were analysed using multivariate regression. RESULTS: Thirty-one per cent of subjects had restorative work, 60% had at least one tooth extracted, 54% had a surgical procedure. Use of local analgesia reduced postoperative pain whilst an increase in the number of surgical procedures increased it. Increase in anaesthetic time was related to increased odds of feeling sleepy and nauseous, females were more likely to complain of sleepiness or weakness. Feelings of dizziness were increased if the patient was given local analgesia during the procedure. CONCLUSIONS: Pain following dental GA was the most prevalent and long lasting symptom of postoperative morbidity in this study. Reductions in operating time and improvement in pain control have the potential to reduce reported morbidity following dental GA.
Effect of hyperinsulinemia on amino acid utilization in the ovine fetus.
We studied the effect of an acute 4-h period of hyperinsulinemia (H) on net utilization rates (AAUR(net)) of 21 amino acids (AA) in 17 studies performed in 13 late-gestation fetal sheep by use of a novel fetal hyperinsulinemic-euglycemic-euaminoacidemic clamp. During H [84 +/- 12 (SE) microU/ml H, 15 +/- 2 microU/ml control (C), P < 0. 00001], euglycemia was maintained by glucose clamp (19 +/- 0.05 micromol/ml H, 1.19 +/- 0.04 micromol/ml C), and euaminoacidemia (mean 4.1 +/- 3.3% increase for all amino acid concentrations [AA], nonsignificantly different from zero) was maintained with a mixed amino acid solution adjusted to keep lysine concentration constant and other [AA] near C values. H produced a 63.7% increase in AAUR(net) (3.29 +/- 0.66 micromol. min(-1). kg(-1) H, 2.01 +/- 0.55 micromol. min(-1). kg(-1) C, P < 0.001), accounting for a 60.1% increase in fetal nitrogen uptake rate (2,064 +/- 108 mg. day(-1). kg(-1) H, 1,289 +/- 73 mg. day(-1). kg(-1) C, P < 0.001). Mean AA clearance rate (AAUR(net)/[AA]) increased by 64.5 +/- 18.9% (P < 0. 001). Thus acute physiological H increases net amino acid and nitrogen utilization rates in the ovine fetus independent of plasma glucose and [AA].
Risk factors for early infection of central venous catheters in pediatric patients.
BACKGROUND: In an effort to avoid infections that can lead to the premature removal of indwelling central venous catheters (CVCs), the surgical technique and host factors present in pediatric recipients of permanent CVCs were reviewed. STUDY DESIGN: All patients receiving CVCs over a 17-month period were identified. Those patients with fever and positive blood cultures drawn through the CVC within 45 days of line placement were labeled as having early infection. A case-control design was used to select two control patients for each infected patient. Charts from both the infection and control groups were reviewed for several factors present at the time of CVC placement, including fever, neutropenia (absolute neutrophil count [ANC] < 500 and ANC < 1,000), use of perioperative antibiotics, diagnosis, CVC site, and type of CVC. Chi-square test with Yates correction was used to compare the groups. Odds ratios (ORs) and 95% confidence intervals were derived. RESULTS: Among the 473 CVCs placed, early infections developed in 53 patients (12%). The control group consisted of 106 patients. Neutropenia was present in 16 of 53 infected patients versus 8 of 106 controls (p = 0.004, OR = 5.30). Perioperative antibiotics were given to 25 of 53 infected patients versus 72 of 106 controls (p = 0.02, OR = 0.42). Fever was present in 12 of 53 infected patients versus 14 of 106 controls (p = 0.19, OR = 1.92). Factors that were equally prevalent between the groups and that did not appear to influence the CVC infection rate included a diagnosis of malignancy, CVC type, and site of placement. Of the 53 infected catheters, 16 (30%) could not be cleared of infection and were removed. CONCLUSIONS: This study documents that neutropenia and failure to administer prophylactic antibiotics are risk factors for the development of early CVC infection in pediatric patients. To avoid early infection and possible premature CVC removal, we recommend that placement of permanent CVCs be postponed until the ANC is > 1,000. Perioperative antibiotics should be given. A trend toward higher infection rates was seen in patients with preoperative fever.
A step forward in paediatric dentistry.
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Half a century of fluoridation.
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Unpredictable teeth.
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An in vitro investigation into the shear bond strengths of two dentine-bonding agents used in the reattachment of incisal edge fragments.
This in vitro study investigated the shear bond strengths of sectioned bovine incisal edge fragments reattached using Gluma 2000 and Scotchbond 2. Teeth were sectioned 3 mm from the incisal edge using an Acutome with a 0.5 mm diamond wheel running at 90 degrees to the mesial or distal surface of the tooth. Twenty four incisal fragments were rebonded with each of the dentine bonding agents; a further 24 intact incisors were used as a control group. The control group required a mean fracture force of 940(+/- 144) N which was significantly greater (p < 0.01) than that required to fracture fragments rebonded using GLUMA 2000 (609 +/- 116) N and Scotchbond 2 (393 +/- 97) N. The mean force required to fracture incisal fragments rebonded with GLUMA 2000 was significantly greater (p < 0.01) than that required to fracture incisal fragments rebonded with Scotchbond 2.
Dihydrolipoic acid prevents hypoxic/reoxygenation and peroxidative damage in rat heart mitochondria.
Fluorescence anisotropy (r) was determined in hypoxic/reoxygenating rat heart mitochondria by means of 1,6-diphenyl-1,3,5-hexatriene. During hypoxia, values for r increased, indicating a rigidified membrane. Membrane fluidity was increased when 20 pmol to 2 nmol/mg protein of dihydrolipoic acid (DHL) was present during hypoxia. Dithiothreitol (DTT) or 2-mercaptopropionylglycin (MPG) at similar concentration did not result in membrane fluidization under these conditions. Peroxidative damage was induced in mitochondria by H2O2. In the presence of 2 nmol/mg protein of DHL, malondialdehyde production was decreased by 50%. DTT or MPG brought about only a 25% decrease. These results were corroborated by spin label studies with 4-maleimido-TEMPO and 5-proxylnonane (5-P-9); H2O2 induced a decrease in fluidity in the region of labeled thiol groups and an increase in polarity sensed by 5-P-9. DHL proved efficient in reducing such fluidity and polarity changes.
Repetitive sequences in the genome of Anemone blanda: identification of tandem arrays and of dispersed repeats.
A tandemly repetitive sequence family (AbS1) and a repetitive sequence (Hd) forming part of a larger dispersed element (dorf-1) of Anemone blanda were characterised. The AbS1 satellite sequence family is located in all 4',6-diamidino-2-phenylindole (DAPI) positive intercalary heterochromatic bands and in the DAPI positive heterochromatic terminal region of chromosome 3, while the dispersed Hd homologous sequences are preferentially associated with euchromatic chromosome regions. The major component of the AbS1 satellite is AbS1-H1 with a basic repeat unit of 1640 bp; a minor fraction (AbS1-H5) consists of 320 bp units. A subsection of the AbS1-H1 repeat unit exhibits homologies to the 25S rRNA gene of flowering plants suggesting that the 1.64 kb satellite was generated by amplification of a precursor satellite and/or single copy sequence together with an rDNA fragment. The rDNA homologous region is considered to evolve at a rate similar to pseudogenes and thus the age of this satellite DNA fraction can be roughly estimated as about 27 million years. The dispersed repeated sequence Hd (about 1300 bp) is associated with the 8 kb element dorf-1. A. blanda dorf-1 constitutes about 0.2% of the genome (3 x 10(4) copies), is bounded by identical long terminal repeats, and exhibits partial homology to the Lilium gypsy-type element del1, but has yet to be confirmed as a retrotransposon. In contrast to the AbS1 satellite sequence family, Hd homologous sequences were found not only in A. apennina, the closest relative of A. blanda, but also in A. nemorosa and A. ranunculoides indicating that a progenitor sequence of dorf-1 was present in a common ancestor before speciation occurred.
Binding of IL-1 beta to alpha-macroglobulins and release by thioredoxin.
Human alpha 2-macroglobulin (H alpha 2M) is a major IL-1 beta binding plasma protein. The characteristics of the H alpha 2M IL-1 beta complex formation suggested, that cleavage of the internal thiol ester in other members of the alpha-macroglobulin family (alpha M) could enable these proteins to bind IL-1 beta. Characterization of optimal conditions for binding 125I IL-1 beta to H alpha 2M showed that H alpha 2M-IL-1 beta complex formation could be obtained over a pH range of 6.3 to 9 in the presence of some metal cations (i.e., Zn2+, Cd2+, Cu2+, Ni2+). Other divalent metal cations (i.e., Mn2+, Mg2+, Ca2+) were without effect. Time kinetic studies showed that binding of IL-1 beta to H alpha 2M was complete within 200 min and that H alpha 2M-IL-1 beta complexes became increasingly resistant to dissociation by boiling in SDS as a function of incubation time. Human pregnancy zone protein, rat alpha 1-, alpha 2-macroglobulin (R alpha 1M, R alpha 2M), all homologous with H alpha 2M, were tested for their ability to bind IL-1 beta. In each instance, alpha M-IL-1 beta complex formation was observed only after treatment of alpha M with methylamine, a primary amine that causes cleavage of the internal thiol ester in alpha M and the appearance of free thiol groups. Similarly, for each of these proteins, complex formation was increased several fold in the presence of Zn2+. Competition experiments using cytokines or proteins of similar molecular mass as IL-1 beta established that only unlabeled IL-1 beta was effective in inhibiting binding of 125I IL-1 beta to H"F" alpha 2M. Acylation of H"F" alpha 2M by diethylpyrocarbonate blocked the binding of IL-1 beta when analyzed by native PAGE. Deacylation of H"F" alpha 2M with hydroxylamine partially restored the binding capacity of H"F" alpha 2M further supporting the involvement of histidyl residues in the Zn2(+)-dependent binding of IL-1 beta. Reduced thioredoxin, but not its alkylated form, from Escherichia coli readily releases H"F" alpha 2M bound IL-1 beta under conditions that did not lead to reduction of disulfide bonds in H"F" alpha 2M. The action of thioredoxin also augmented IL-1-like activity in two independent bioassays suggesting that H"F" alpha 2M bound IL-1 beta is partially biologically inactive or latent. These results suggest that "activated" alpha M exert a modulating role for IL-1 beta by exposing specific binding sites, which are inaccessible in the native proteins.(ABSTRACT TRUNCATED AT 400 WORDS)
Emergency treatment of avulsed incisor teeth.
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'Changing perceptions of the requirements of cavity preparations'.
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Hand over mouth technique.
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Caries in children--the dietary factor.
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