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Biomedical subjects

S Mitchell

Publications and source records attributed to S Mitchell.

At least 37 records · Page 2Linked to original sources
PubMed2003

Feasibility, accuracy and optimal location for oesophageal core temperature measurements using the ProSeal laryngeal mask airway drain tube.

We determined the feasibility, accuracy and optimal location of oesophageal core temperature measurements using the ProSeal laryngeal mask airway drain tube. Thirty normothermic anaesthetized ventilated adults (ASA 1 to 2, aged 18 to 80 years) were studied. Temperatures were recorded using a thermistor at six different locations (middle of drain tube and at 0 to 20 cm distal to the drain tube in 5 cm increments) and compared to nasopharyngeal (thermistor) and aural (infrared tympanic thermometer) reference core temperatures. The temperature probe was successfully inserted into the oesophagus in all patients at the first attempt. Oesophageal temperature increased with depth from 0 to 5 cm (35.2 v 35.9, P < 0.0001) and 5 to 10 cm (35.9 v 36.3, P < 0.01), but was unchanged from 10 to 15 cm (36.3 v 36.6) and 15 to 20 cm (36.6 v 36.7). Aural temperature was higher than nasopharyngeal temperature (36.8 v 36.0, P < 0.0001). Aural temperature was 0.89 to 1.59 degrees C higher than the oesophagus at 0 to 5 cm and 0.21 to 0.30 degree C higher than the oesophagus at 15 to 20 cm. Nasopharyngeal temperature was 0.06 to 0.76 degree C higher than the oesophagus at 0 to 5 cm and 0.62 to 0.84 degree C lower than the oesophagus at 15 to 20 cm. The lowest temperature was in the mid-point of the drain tube (34.7). We conclude that oesophageal core temperature measurement is feasible and accurate using the ProSeal laryngeal mask airway. The optimal location for the temperature probe is at 15 to 20 cm.

Adult↗
PubMed2003

Adjunctive treatment of decompression illness with a non-steroidal anti-inflammatory drug (tenoxicam) reduces compression requirement.

We report a randomized trial examining adjunctive administration of the NSAID, tenoxicam, to divers suffering with DCI. 180 subjects were graded for severity on admission and randomized according to a stratified random number schedule. Subjects were recompressed and treatment continued daily until symptom stabilization or complete resolution. Tenoxicam 20 mg or a placebo preparation was administered at the first air break during the initial recompression and continued daily for seven days. The subjects were assessed using a recovery status score at the completion of treatment and at 4-6 weeks. The proportion of patients with mild residual symptoms at discharge and final follow-up was not significantly different (discharge placebo 30% versus tenoxicam 37%, P=0.41; six weeks placebo 20% versus tenoxicam 17%, P=0.58). There was a significant reduction in the number of treatments required to achieve discharge (median treatments placebo 3, tenoxicam 2, P=0.01). 61% of patients in the tenoxicam group required less than 3 compressions, versus 40% in the placebo group (P=0.01, RRR 33 % [95%CI 9%-56%], NNT=5 [95%CI 3-18]). There was no evidence of increased complications of treatment in the tenoxicam group. When given this NSAID, patients with DCI require fewer hyperbaric oxygen (HBO2) sessions to achieve a standard clinical end-point and there is likely to be an associated cost saving.

Adult↗
PubMed2002

The genetic control of IgA activity against Teladorsagia circumcincta and its association with parasite resistance in naturally infected sheep.

Previous studies in deliberately infected sheep have shown an association between IgA activity against 4th-stage larvae of Teladorsagia circumcincta and parasite growth, development and fecundity. The purpose of this research was to determine if these results could be confirmed in naturally infected sheep and to explore the hypothesis that plasma IgA activity could help to identify resistant lambs with shorter adult nematodes. Plasma IgA activity was skewed with most animals having relatively low levels of IgA activity. Plasma IgA activity was repeatable and highly heritable. Animals with increased IgA activity had lower egg counts and shorter adult female T. circumcincta. Therefore, under conditions of natural parasite challenge, plasma IgA activity may help to identify lambs resistant to T. circumcincta.

Animals↗
PubMed2002

Eosinophilia as a marker of resistance to Teladorsagia circumcincta in Scottish Blackface lambs.

Faecal egg counts and peripheral blood eosinophil counts were taken from Scottish Blackface lambs following natural, predominantly Teladorsagia circumcincta infection. Peripheral eosinophil concentrations were higher in animals with lower egg counts but only in lambs that were at least 3 months of age. The reduced egg counts were due to reduced fecundity of T. circumcincta; there was no association with the number of adult T. circumcincta. Associations with the number of parasites from other species of gastrointestinal nematodes appeared to be neutral or favourable. Estimated heritabilities for eosinophil concentrations in 4- and 5-month-old lambs were 0.48 +/- 0.16 and 0.43 +/- 0.17, respectively. Therefore, under defined circumstances, eosinophil concentrations may be a useful indicator of resistance to predominantly T. circumcincta infection.

Animals↗
PubMed2002

Cholangiocarcinoma in primary sclerosing cholangitis: risk factors and clinical presentation.

BACKGROUND: Primary sclerosing cholangitis (PSC) confers a high risk of cholangiocarcinoma (CC) development. Since patients at risk of CC may be selected for early liver transplantation, it is a challenge to identify any predisposing factors. We compared the presentation and natural history of a large number of PSC patients with and without later CC development to identify features associated with risk of CC. METHODS: Clinical and laboratory data from presentation and follow-up were collected from 394 PSC patients from five European countries. The cohort included 48 (12.2%) patients with CC. RESULTS: CC was diagnosed within the first year after diagnosis of PSC in 24 (50%) cases and in 13 (27%) patients at intended liver transplantation. Jaundice, pruritus, abdominal pain and fatigue were significantly more frequent at diagnosis of PSC in the group that developed CC, but not after exclusion of cases diagnosed within the first year. Inflammatory bowel disease was diagnosed at least 1 year before PSC more often among patients with CC development than among those without (90% and 65%, respectively: P = 0.001). The duration of inflammatory bowel disease before diagnosis of PSC was significantly longer in patients who developed CC than in the remaining group (17.4 years and 9.0 years, respectively: P=0.009 in multivariate analysis). CONCLUSIONS: A high proportion of CC cases is diagnosed within the first year after diagnosis of PSC. A long history of inflammatory bowel disease is a risk factor for CC development.

Adult↗
PubMed2001

Direct measurements of colloidal friction coefficients.

The time-independent hydrodynamic forces operating between two hard spheres were studied as a function of the interparticle separation r. Two colloids were positioned a distance r apart using a dual-beam optical tweezer similar to that described by Meiners and Quake [Phys. Rev. Lett. 82, 2211 (1999)]. Brownian fluctuations in the positions of the two spheres were followed by recording the intensity of forward scattered laser light. The two particles move cooperatively as a result of hydrodynamic forces. The strength of the correlation increased strongly with decreasing separation r. We show that the temporal and spatial correlations in the particle displacements are determined by the distance dependence of the pair friction tensor xi. The distance and geometry dependence of the measured friction tensor is found to be in excellent agreement with the predictions of low-Reynolds number calculations.

Journal Article↗
PubMed2001

Lipoxins: revelations on resolution.

Lipoxins (LXs) are endogenously produced eicosanoids typically generated during cell-cell interactions. In this article, the compelling evidence from in vitro and in vivo model systems that LXs actively promote the resolution of inflammation is reviewed. Of particular interest are indications that stable synthetic analogues of LXs and aspirin-triggered 15-epi-LXs can mimic many of the desirable anti-inflammatory, "pro-resolution" actions of native LXs. Given the enhanced stability and efficacy of these compounds a role as novel anti-inflammatory therapeutics is proposed.

Animals↗
PubMed2001

Principles of molecular microbiology testing methods.

Molecular testing methods have the potential to replace many conventional microbiology laboratory assays. Recent refinements in technology have resulted in more user-friendly testing platforms. These platforms are automated and have lowered risks for contamination, decreased costs, and are faster than older platforms. The success of these technologies depends on their successful application to patient care. Quality issues include appropriate specimens for analysis, performance characteristics of different analytical methods, optimal specimen processing, the effects of PCR inhibitors, and false-positive results caused by contaminating nucleic acids. Quality control guidelines for molecular microbiologic diagnostic assays are in their infancy and require further development. Additionally, the problem of "too much" sensitivity (brought on by the extreme sensitivity of these techniques coupled with the potential presence of small numbers of pathogenic organisms in asymptomatic individuals) should be considered. Potential problems when monitoring therapy (because molecular detection techniques do not generally have the ability to determine whether an organism is dead or alive) can also occur. Cost-effective test use, pathogen- or disease-targeted algorithms, and standardized methods will be necessary for the true value of these technologies to be realized. This is especially important, because, unlike traditional culture methods, most molecular microbiology methods are pathogen-specific. Clinicians familiar with the reasons why "pan-culture" (i.e., requesting all culture possibilities at once) is inadvisable should not use the same irrational approach when requesting molecular tests. The clinical usefulness of molecular testing will be maximized as targeted algorithms are developed and an understanding of molecular test ordering patterns is realized. Laboratory technicians and physicians must continue to apply and combine theories of traditional microbiology, clinical chemistry, and general medicine to the understanding and application of molecular diagnostics.

Base Sequence↗
PubMed2001

Fructosamine concentration and resistance to natural, predominantly Teladorsagia circumcincta infection.

Fructosamine concentrations reflect protein status and because infection with Teladorsagia circumcincta can induce a relative protein deficiency, we examined the usefulness of fructosamine concentrations as markers of the intensity of infection in naturally infected lambs. Fructosamine concentration was a heritable trait and variation in fructosamine concerntrations was associated with differences in body weight, and a variety of parasitological variables; animals with increased fructosamine concentrations grew more quickly, had increased faecal egg counts in one of the three study years, had decreased pepsinogen concentrations and decreased IgA activity against 4th-stage larvae of T. circumcincta. Fructosamine concentrations were also associated with variation in the subsequent acquisition of nematodes and in the length of adult female T. circumcincta; lambs with increased fructosamine concentrations had fewer nematodes but the mean length of adult female T. circumcincta was longer. Therefore fructosamine concentrations are potentially useful indicators of the severity of nematode infection and may predict magnitude of subsequent infection.

Abomasum↗
PubMed2001

Use of a structured investigative protocol enhances young children's responses to free-recall prompts in the course of forensic interviews.

One hundred alleged victims of child sexual abuse (ages 4-12 years; M = 8.1 years) were interviewed by police investigators about their alleged experiences. Half of the children were interviewed using the National Institute of Child Health and Human Development's structured interview protocol, whereas the other children--matched with respect to their age, relationship with the alleged perpetrator, and seriousness of the alleged offenses--were interviewed using standard interview practices. Protocol-guided interviews elicited more information using open-ended prompts and less information using option-posing and suggestive questions than did standard interviews; there were no age differences in the amount of information provided in response to open-ended invitations. In 89% of the protocol interviews, children made their preliminary allegations in response to open-ended prompts, compared with 36% in the standard interviews.

Child↗
PubMed2001

A functional polymorphism of the stromelysin gene (MMP-3) influences susceptibility to primary sclerosing cholangitis.

BACKGROUND AND AIMS: We have investigated the influence of a biallelic polymorphism of the promoter region of stromelysin (matrix metalloproteinase 3) on susceptibility to primary sclerosing cholangitis (PSC). The 5A allele is associated with increased transcription, compared with wild-type (6A). METHODS: An allelic association study was performed: in stage 1, 52 PSC patients (43 with inflammatory bowel disease [IBD]) and 99 healthy subjects (HS) were genotyped. In stage 2, 59 PSC patients (49 IBD), 84 patients with uncomplicated ulcerative colitis, and 72 HS were genotyped. RESULTS: In stage 1, 5A carriage rate (90.4% vs. 72.7%; P = 0.012) and 5A allelic frequency (65.4% vs. 48.5%; P = 0.005) were increased, and 6A homozygosity was reduced in PSC (9.6% vs. 27.3%; P = 0.012). In stage 2, 5A allelic carriage was increased in PSC (93.2% vs. 76.4% in HS; P = 0.0092) and 6A homozygosity was reduced (6.8% vs. 23.8% in HS; P = 0.0092). Portal hypertension was associated with 5A homozygosity in PSC (P = 0.035; odds ratio [OR], 3.88). In the combined data set, 5A allelic frequencies (63.5% vs. 49.4%; P = 0.001; OR, 1.78) and 5A carriage rates (91.9% vs. 74.2%; P = 0.0002; OR, 3.92) were increased, and 6A homozygosity was reduced in PSC (8.1% vs. 25.7%; P = 0.0002; OR, 0.25). Overall, portal hypertension was associated with 5A homozygosity (P = 0.0192; OR, 3.12). CONCLUSIONS: Stromelysin polymorphism may influence susceptibility and disease progression in PSC.

Adult↗
PubMed2001

The HLA-DR3,DQ2 heterozygous genotype is associated with an accelerated progression of primary sclerosing cholangitis.

BACKGROUND: An improvement of prognostic models in primary sclerosing cholangitis (PSC) is needed. In particular, inclusion of prognostic markers that are independent of the disease stage would be advantageous. We investigated whether HLA class II genes associated with PSC are also related to disease progression. METHODS: The study included 265 PSC patients from five European countries with a median follow-up of 9.1 years. The end-points were death (n = 38) or liver transplantation (n = 52). Thirty patients developed cholangiocarcinoma during follow-up. RESULTS: The DRB1*03,DQA1*0501, DQB1*02 (i.e. DR3,DQ2) heterozygous genotype was associated with an increased risk of death or liver transplantation (hazard ratio = 1.63; 95% confidence interval (CI) = 1.06-2.52). The presence of a DQ6 encoding haplotype (DQB1*0603 or DQB1*0602) in DR3,DQ2 negative individuals was associated with a reduced risk of death or liver transplantation (hazard ratio = 0.57; 95% CI = 0.36-0.88). There was a trend towards an increased risk of developing cholangiocarcinoma among DR4,DQ8 positive patients, but this did not reach significance (odds ratio = 2.27; 95% CI = 0.78-6.62). CONCLUSION: The DR3,DQ2 heterozygous genotype is associated with a more rapid progression of PSC, whereas HLA-DQ6 is associated with a retarded disease progression. It is possible that the DR4,DQ8 haplotype is related to cholangiocarcinoma development.

Adolescent↗
PubMed2001

Human perceptions of sports equipment under playing conditions.

Assessment of the 'performance' of sports equipment is generally derived from physical and technical parameters, such as power, speed, distance and accuracy. However, from a psychological perspective, players need to feel comfortable with their equipment and confident in its properties. These factors can only be measured through the subjective assessment of individual perceptions. Focusing on a group of elite golfers, this study presents a formalized approach for eliciting and structuring players' descriptions of their perception of sports equipment. Qualitative methods of inquiry were used to generate perceptions from a group of professional golfers (n = 15) during play testing. The equipment characteristics of significance to the golfers emerged from an inductive analysis of their responses. However, although this method of representation of the results helped to identify the key components or dimensions of a player's subjective perception, it was unable to determine potential relationships between the dimensions. With this in mind, a new technique, called 'structured relationship modelling', was developed. Ten general dimensions emerged from the analysis, of which three are presented here together with a section of the relationship model. The results demonstrate the effectiveness of qualitative techniques for eliciting human perceptions and of structured relationship models for representation of the associations found.

Adult↗
PubMed2001

Effect of composite resin placement techniques on the microleakage of two self-etching dentin-bonding agents.

PURPOSE: To evaluate microleakage of Class V resin-based composites (RBC) bonded with two self-etching dentin adhesive systems. Class V cavities were restored with either one or three increments of RBC to determine whether the restorative method affected microleakage. MATERIALS AND METHODS: 60 extracted human premolars and molars were randomly assigned to 6 groups for bonding with Clearfil Liner Bond 2V or Etch & Prime 3.0 or Prime & Bond NT. The latter, using a total-etch technique, was used as a control. Cavities were cut in both the buccal and lingual surfaces. Half of each preparation was in enamel and half was in cementum/dentin. The teeth were thermocycled and the restorations examined microscopically for leakage using Procion Brilliant Red as a marker. SEM microphotographs were prepared from dye-labeled and non dye-labeled areas to illustrate the micromorphology of the systems. RESULTS: None of the groups showed microleakage at the enamel margins. All groups showed microleakage at the gingival margins. At the gingival margin, there was no significant difference between the groups irrespective of the bonding material (Kruskal-Wallis: ANOVA P=0.2113). No significant difference was observed with each material when the bulk filling (one increment) technique was compared with the three-increment technique. SEM showed that the self-etching materials produced a shallower depth of etch, and a less abundant resin tag complex than the material using a separate phosphoric acid gel. In dye-labeled areas, debonding was predominantly cohesive in resin. CLINICAL SIGNIFICANCE: Gingival margin microleakage is not prevented by either restoring cavities with self-etching materials of the control using a total-etch technique.

Acid Etching, Dental↗