Bronchoscopy technique.
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Anesthesia, General↗
Biomedical subjects
A Richards
Publications and source records attributed to A Richards.
The effects of cueing target location and response mode on interference and negative priming using a visual selection paradigm.
Two experiments are reported that examine the effects of cueing the location of a target in the prime display on interference and subsequent negative priming . The prime and probe displays comprised two words, a target and a distractor. In the prime display, the two words were either the same (response compatible) or different (response incompatible). The target in the probe display was unrelated to the prime distractor (control), the same word as the distractor (ignored repetition), or semantically related to the distractor (ignore semantic repetition). In Experiment 1, cueing the location of the prime target significantly reduced the interference effect but not the subsequent identity negative priming (NP) effect. In contrast, not cueing the prime target resulted in the elimination of the identity NP. There was no evidence of semantic NP in this experiment. In Experiment 2, where a categorization response was required, significant interference was obtained in the prime display that was not influenced by cueing the location of the target. Although there was significant semantic NP, identity NP failed to reach significance. The two experiments were analysed together, and findings are discussed in relation to current models of negative priming.
Analysis of Variance↗
Reasons for delayed compliance with the childhood vaccination schedule and some failings of computerised vaccination registers.
OBJECTIVE: To identify reasons for delay in completing the primary vaccination schedule. METHOD: Brisbane, Queensland, 1995. Telephone interviews of a random sample of parents whose children according to a computerised database were fully vaccinated (100 parents) and parents whose children had commenced but not completed vaccination (200 parents). RESULTS: The main reason for delaying vaccinations was medical advice to do so because of false contra-indications. The most significant factor in predicting timely vaccination, was the belief that giving vaccinations at the correct time was "very important", odds ratio 2.07 (95% CI 1.32-3.26). Eighty-six per cent of the children of interviewed parents from the group recorded as not fully vaccinated were in fact fully vaccinated. CONCLUSIONS: The most important predictors of vaccination behaviour are the advice provided by medical practitioners and parental beliefs. Computerised vaccination records can seriously underestimate vaccination rates. IMPLICATIONS: Vaccination providers and the public need accurate knowledge about both the need for timely vaccination and the real contraindications to vaccination. For a vaccination register to record vaccination status with accuracy, service providers need to be highly co-operative in completing and returning vaccination records, and central data entry needs to be comprehensive and accurate.
Attitude to Health↗
A system for microscope-assisted guided interventions.
We present a system for surgical navigation using stereo overlays in the operating microscope aligned to the operative scene. This augmented reality system provides 3D information about nearby structures and offers a significant advancement over pointer-based guidance, which provides only the location of one point and requires the surgeon to look away from the operative scene. With a previous version of this system, we demonstrated feasibility, but it became clear that to achieve convincing guidance through the magnified microscope view, a very high alignment accuracy was required. We have made progress with several aspects of the system, including automated calibration, error simulation, bone-implanted fiducials and a dental attachment for tracking. We have performed experiments to establish the visual display parameters required to perceive overlaid structures beneath the operative surface. Easy perception of real and virtual structures with the correct transparency has been demonstrated in a laboratory and through the microscope. The result is a system with a predicted accuracy of 0.9 mm and phantom errors of 0.5 mm. In clinical practice errors are 0.5-1.5 mm, rising to 2-4 mm when brain deformation occurs.
Bone Cysts↗
Factors influencing the speed of sound through the proximal phalanges.
The amplitude-dependent speed of sound (AD-SOS) in the proximal phalanges is reported to be sensitive to osteoporotic changes. We investigated the influence of bone thickness and cortical thickness on AD-SOS. Phantoms made of Perspex were designed to simulate different bone width (11-16 mm) and cortical thickness (3-7.5 mm). The phantoms were designed with two opposing flat and cylindrical surfaces. The effect of cortical thickness was examined by drilling holes (simulating the medullary canal) of different diameters (1-7 mm) in the middle of the Perspex cylinders. The effect of sample thickness was investigated on solid Perspex phantoms of varied lengths. The standardized precision errors of AD-SOS measurement in vivo and in vitro on volunteers and phantoms were 2.8 and 0.9%, respectively. AD-SOS was influenced by the bone width, cortical thickness, and location along the phalanx. A decrease in either cortical width or cortical thickness resulted in a decrease in AD-SOS. The effect is dependent on whether the contact surface is curved or flat. It is possible that a curved surface has a focusing effect on the wave through the porous core, whereas for a flat surface, the path of the waves might not pass through the center. When cortical thickness and bone width were expressed as a ratio, there was a linear relationship between this ratio and AD-SOS through the phantoms. AD-SOS was independent of thickness for samples greater than 11 mm.
Adult↗
Sialadenosis: a presenting sign in bulimia.
BACKGROUND: Sialadenosis refers to noninflammatory, often recurrent, enlargement of the salivary glands, most frequently the parotids, which is almost always associated with an underlying systemic disorder. These include diabetes, alcoholism, malnutrition, anorexia nervosa, and bulimia. It is thought that the various causes of sialadenosis all result in a common pathogenetic effect in that they produce a peripheral autonomic neuropathy which is responsible for disordered metabolism and secretion, resulting in acinar enlargement. METHODS: This paper reports a case of sialadenosis as a presenting sign in bulimia and studies the histologic and electron microscopic features of this disease. RESULTS: Light microscopy showed acini which appeared to be larger than normal and which were composed of plump pyramidal cells containing prominent zymogen granules. There was less interstitial fat, and the ducts were widely dispersed. Electron microscopy showed the acinar cells to be packed with membrane-limited, dark secretory granules some of which showed moulding of their outlines. Cellular organelles and nuclei were inconspicuous. CONCLUSIONS: Management of sialadenosis depends upon identification of the underlying cause, which must then be corrected. In bulimia, the swellings may be refractory to standard treatment modalities, and parotidectomy may be considered as a last resort to improve the unacceptable aesthetics.
Adult↗
Mistakes around the clock: errors in memory for the orientation of numerals.
Recent research has demonstrated that when participants are required to draw from memory a standard clock with numbers represented by Roman numerals, they typically misrepresent the four as "IV" rather than as the correct "IIII." Participants do not make this mistake when they simply copy the clock while it remains in full view. A reanalysis of the data presented by Richards, French, and Harris (1996) is reported in which we investigated the representation of the orientation of the Roman numerals on the clockface and found that participants in the memory conditions (surprise and forewarned) were more likely than participants in the copy (control) condition to draw the numerals vertically rather than in their correct centripetal orientation. In addition, we found this error was even more likely to occur for participants when they had no warning that a memory task would take place.
Adult↗
Immune response against the exp-1 protein of Plasmodium falciparum results in antibodies that cross-react with human T-cell lymphotropic virus type 1 proteins.
To examine the role of the Plasmodium falciparum Exp-1 blood-stage protein in producing antibodies that cross-react with human T-cell lymphotropic virus type I (HTLV-I) proteins, we studied sera from Indonesian volunteers who seroconverted to malaria after transmigrating to an area where malaria is hyperendemic. Samples from Philippine volunteers, that were used in a prior study that examined malaria antibodies that cross-react with HTLV-I proteins, were also used. Eighty-three percent of the Indonesian transmigrants developed antibodies against the malaria Exp-1 protein by 6 months postmigration. Of these malaria seroconverters, 27% developed false-positive HTLV-I enzyme immunoassay (EIA) immunoreactivity, as indicated by indeterminate HTLV-I Western blot banding patterns. Five of the six Philippine samples tested were HTLV-I EIA false positive and Western blot indeterminate. When a recombinant Exp-1 protein was used in blocking experiments, the HTLV-I Western blot immunoreactivity of sera from both groups was either completely eliminated or greatly reduced. No effect on the Western blot immunoreactivity of truly HTLV-I-positive sera was seen. To determine if immunization with the recombinant Exp-1 protein could elicit the production of HTLV-I antibodies, six mice were inoculated with the recombinant protein. Following administration of three 50-microgram doses of the protein, four of the six mice developed antibodies that cross-reacted with HTLV-I proteins on Western blot. These results indicate that the immune response against the malaria Exp-1 protein may result in HTLV-I-cross-reacting antibodies that can lead to false-positive EIA and indeterminant Western blotting results.
Animals↗
Ecological considerations for the environmental impact evaluation of recombinant baculovirus insecticides.
The history of baculoviruses in insect control and the current status of recombinant baculovirus (recBV) insecticides in the laboratory and the field are briefly outlined. A conceptual model for impact evaluation is described that distinguishes between scientific impact evaluation and regulatory risk assessment. Its components are identified and reviewed in the light of existing ecological theory and experimental study under the categories of impact identification, exposure identification, and impact evaluation. Impact identification aims to identify species and populations sensitive to direct or indirect impacts by a recBV. Exposure identification examines how susceptible populations may be exposed to a recBV. Impact evaluation combines these data to predict the potential for recBV impacts in the environment.
Journal Article↗
Involvement of yeast sphingolipids in the heat stress response of Saccharomyces cerevisiae.
A role for sphingolipids in the yeast heat stress response has been suggested by the isolation of suppressors of mutants lacking these lipids, which are unable to grow at elevated temperatures. The current study examines the possible role of sphingolipids in the heat adaptation of yeast cells as monitored by growth and viability studies. The suppressor of long chain base auxotrophy (SLC, strain 7R4) showed a heat-sensitive phenotype that was corrected by transformation with serine palmitoyltransferase. Thus, the deficiency in sphingolipids and not the suppressor mutation was the cause of the heat-sensitive phenotype of the SLC strain 7R4. The ability of sphingolipids to rescue the heat-sensitive phenotype was examined, and two endogenous yeast sphingoid backbones, phytosphingosine and dihydrosphingosine, were found to be most potent in this effect. Next, the effect of heat stress on the levels of the three major classes of sphingolipids was determined. The inositol phosphoceramides showed no change over a 1.5-h time course. However, the four detected species of sphingoid bases increased after 15 min of heat stress from 1.4- to 10.8-fold. The largest increases were seen in two sphingoid bases, C20 phytosphingosine and C20 dihydrosphingosine, which increased 6.4- and 10.8-fold over baseline, respectively. At 60 min of heat stress two species of yeast ceramide increased by 9.2- and 10.6-fold over baseline. The increase seen in the ceramides was partially decreased by Fumonisin B1, a ceramide synthase inhibitor. Therefore, heat stress induces accumulation of sphingoid bases and of ceramides, probably through de novo synthesis. Taken together, these results demonstrate that sphingolipids are involved in the yeast heat stress adaptation.
Chromatography, High Pressure Liquid↗
The structural organisation of LAMA4, the gene encoding laminin alpha4.
We have determined the complete structural arrangement of LAMA4, the gene encoding the laminin alpha4 chain. Using both yeast artificial chromosome clones and total human genomic DNA and primers derived from the cDNA sequence, regions of the gene were amplified and sequenced to determine the splice donor and acceptor sites. The introns were sized by agarose gel electrophoresis of the PCR products. The gene consisted of 39 exons spanning 122 kb. All of the splice sites conformed to the GT/AG rule, except intron 7 which possessed a GC dinucleotide at the donor splice site. The intron/exon ratio was large at 17.8:1, mainly due to large introns at the 5' end of the gene. Regions at both the 5' and 3' end of the gene were subcloned from the yeast artificial chromosomes to enable untranscribed DNA to be sequenced. The gene represents the second of the laminin A gene family to be characterised and its structural organisation is similar to the equivalent regions of the LAMA2 gene.
Amino Acid Sequence↗
Fluoride content and mineralization of red deer (Cervus elaphus) antlers and pedicles from fluoride polluted and uncontaminated regions.
Fluoride, calcium, and phosphorus content as well as ashpercentage and ash density of primary antlers and pedicle bones were studiedin nine yearling red deer stags from a fluoride polluted region in NorthBohemia (Czech Republic) and in nine control animals from two uncontaminatedareas in West Germany. Fluoride levels in antlers (845 +/- 257 mgF-/kg ash, mean +/- SD) and pedicles (1,448 +/- 461 mgF-/kg ash) of the N-Bohemian specimens exceeded that of thecontrols (antlers: 206 +/- 124 mg F-/kg ash, pedicles:322 +/- 157 mg F-/kg ash) by factors of 4.1 and 4.5,respectively. Antler and pedicle fluoride concentrations of the deer(n = 18) were closely correlated (r = 0.975,p < 0.001). Analyses of ash percentage and ash density revealed that theantlers of the N-Bohemian deer contained significantly less mineral and weresignificantly less dense than both their pedicles and the control antlers. Inthe pooled antler samples (n = 18), bone fluoride concentration wasnegatively correlated with ash density (r = -0.826, p < 0.001)and ash percentage (r = -0.759, p < 0.001), whereas nonsignificant, positive correlations existed for the pooled pedicle samples. Ash percentage and ash density of the antlers and their correspondingpedicles were uncorrelated. It is concluded that increased fluoride exposureof deer leads to reduced mineral content and mineral density of antler boneand that it is the rapidity of their growth and mineralization that makesantlers especially susceptible to fluoride action. Due to their ability toaccumulate high amounts of fluoride during a defined, limited timespan andthe apparently dose-dependent negative effect of fluoride on their densityand mineral content, (primary) antlers can be recommended as monitoring toolsfor studying environmental pollution by fluorides.
Animals↗
Running an objective structured clinical examination on a shoestring budget.
BACKGROUND: A major obstacle in the wide implementation of objective clinical structured examinations (OSCEs) is their high cost, averaging $200 to $300 (Canadian dollars, CDN) per candidate and estimated at up to CDN$900 per candidate if all "hidden" administrative costs are included. METHODS: A detailed cost analysis of preparing and administering OSCEs at 1 institution was undertaken over 2 years. An 18-station, 6-minute-per-station OSCE was given to a 72-student third-year medical class. RESULTS: The total cost of the OSCE was CDN$5,010, or $70 per student. The key factors in reaching this significantly lower per-student OSCE cost included: judicious use of standardized patients, use of academic faculty for preparing and marking the stations, and decreased secretarial and other administrative costs. CONCLUSIONS: Data suggest that OSCEs can be set up with reasonable cost and limited resources even in smaller institutions. Cost should not be considered a major obstacle in implementing this excellent examination type in undergraduate medical education.
Canada↗
Anxiety and memory: a recall bias for threatening words in high anxiety.
Few studies have directly examined the relationship between trait anxiety and explicit memory for emotionally congruent material. Evidence from clinically anxious subjects, however, suggests a recall bias favouring non-threatening words as opposed to threatening words. Two experiments are reported which examined the recall performance of high- and low-trait anxious subjects. Contrary to the clinical anxiety findings, there was evidence of a recall bias for threatening rather than non-threatening words in the high-trait anxious group. Further analysis, however, revealed that the recall bias was associated with state anxiety and depression levels rather than trait anxiety. The two experiments also showed that recall was greater for words appearing at the end of the list as opposed to words presented elsewhere in the list. The theoretical and methodological implications of these findings are discussed.
Adult↗
A comparison of the effects of two anabolic agents (fluoride and PTH) on ash density and bone strength assessed in an osteopenic rat model.
The aim of this investigation was to compare the effects of sodium fluoride (NaF) and parathyroid hormone (PTH) on ash density and strength in an osteopenic rat model. The study comprised 66 female virgin rats divided into the following 11 groups, each comprising six animals: baseline controls; baseline ovariectomized (ovx); intact controls (5 and 16 weeks), ovx controls (5 and 16 weeks); ovx-treated with PTH (0.02 mg/kg per day, 5 and 16 weeks); ovx treated with NaF (10 mg/kg per day, 5 and 16 weeks); ovx-treated with NaF (1.0 mg/kg per day, 16 weeks). Ovariectomy was performed at 12 weeks of age, 14 weeks prior to start of treatment. Ash density, bone fluoride content, and biomechanical analyses were performed on femoral cortical bone, the right femoral neck, and the sixth lumbar vertebral body. ovx had no effect on cortical bone, whereas the femoral neck displayed a significantly lower bone strength in ovx baseline animals compared with intact baseline rats (p < 0.05). Vertebral ash density was found to be significantly decreased in ovx rats after 5 and 16 weeks (p < 0.05). Treatment with fluoride had little effect on the osteopenic rat skeleton. Cortical ash density was significantly lower than ovx and intact groups in the high-dose-treated rats after 5 (p < 0.01) but not after 16 weeks. High doses of fluoride for 16 weeks induced a significant increase in maximum load and normalized strength in cortical bone when compared with intact animals (p < 0.05), but not at the other bone sites. Cortical bone strength was not different from the ovx animals at either timepoint. In fluoride-treated animals, femoral neck bone strength, vertebral body bone strength, bone quality, and ash density were found to be at about ovx levels and, in the vertebral body, significantly lower than intact animals (p < 0.05, p < 0.01). In contrast, treatment with PTH increased ash density, bone strength, and bone quality to above ovx levels (p < 0.01), and above the level of the intact animals also, although significant values were reached for cortical bone strength only (p < 0.01). Additionally, biomechanical competence and ash density measurements were significantly higher in PTH-treated rats compared with fluoride-treated rats. In conclusion, this study has shown that PTH has a highly anabolic effect and is capable of effectively restoring ovx-induced loss of bone mass and biomechanical competence. In addition, in this osteopenic rat model, PTH proved much more advantageous than treatment with fluoride, which failed to restore the ovx-induced loss of bone strength.
Animals↗
Cognitive processing and trait anxiety in typically developing children: evidence for an interpretation bias.
In this study the authors examined whether increases in children's levels of self-reported trait anxiety would be related to their interpretation of ambiguous stimuli. By using the Revised Children's Manifest Anxiety Scale (C. R. Reynolds & B. O. Richmond, 1985), the authors obtained measurements of anxiety for 40 children ages 7 and 9 years. Interpretation of ambiguous stimuli was measured by using a pictorial homophone task, where homophones could be interpreted as either threatening or neutral. Results showed that children's interpretations of homophones was significantly predicted by level of anxiety. Increases in levels of trait anxiety were positively associated with threatening interpretations of homophones.
Anxiety↗
A comparison of sevoflurane with halothane for paediatric day case surgery.
A phase III, open label randomized study was conducted in 50 patients comparing halothane and sevoflurane for paediatric day case surgery. A graded inhalational induction resulted in only slightly more rapid induction with sevoflurane (3.34 +/- 0.92 versus 3.85 +/- 1.02 minutes; P > 0.05). In children receiving sevoflurane, systolic blood pressure decreased to a lesser extent during induction (143 +/- 19.2 versus 26.9 +/- 10.9 percent decrease from resting values; P < 0.01) and heart rate was maintained. Respiratory events (coughing, breath-holding, bronchospasm, laryngospasm) were more common during induction with halothane, and excitement more common in children receiving sevoflurane. Emergence times were significantly more rapid in children who had received sevoflurane (21.4 +/- 10.9 versus 33.1 +/- 13.7 minutes; P < 0.01). Objective pain/discomfort scores were higher in patients receiving sevoflurane at 10, 20, 30 and 40 minutes after arrival in the recovery room, and the incidence of excitement during emergence was higher in this group. It is concluded that sevoflurane is well tolerated for inhalational induction and has an improved cardiovascular profile compared to halothane. Emergence was significantly more rapid following sevoflurane.
Adolescent↗
Surgery on the Internet. Part 1: The origins of the Internet.
The last few years have seen a dramatic increase in the size and use of the Internet; indeed recent figures estimate that the number of people with Internet access is increasing by up to 20 per cent monthly with over 30 million people now connected world wide. Many organisations, including The Royal College of Surgeons of England, now offer their own world wide web (WWW) sites. There are a number of areas and facilities on the Internet which are of particular interest to the surgeon; these include access to journals and textbooks, information of surgical units world-wide, e-mail and newsgroups discussing various surgical topics. The aim of this article, together with the two others in the series is to explain the steps necessary to get connected to the Internet and to illustrate some of the main areas of interest to the surgeon. This, the first of the articles will describe the origins of the Internet and the equipment and process required to get connected.
Computer Communication Networks↗