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Biomedical subjects

A Wright

Publications and source records attributed to A Wright.

At least 19 recordsLinked to original sources
PubMed2002

Temporal summation of pain from skin, muscle and joint following nociceptive ultrasonic stimulation in humans.

This study investigated the phenomenon of temporal summation in response to repetitive focused ultrasound stimulation of skin, muscle and joint in human volunteers. Stimulation was carried out using a custom-designed, focused ultrasonic stimulator with a resonant frequency of 1.66 MHz. A series of stand-off attachments were used to ensure that the focal region of the ultrasound beam projected either cutaneously, within the distal interphalangeal joint of the index finger, or within the first dorsal interosseous muscle. Stimulation was carried out using single pulses and trains of five pulses of different pulse durations (25 ms, 50 ms, 75 ms, 100 ms), and using single pulses and trains of five pulses (50 ms duration) at different frequencies (0.5 Hz, 1 Hz, 2 Hz, 3 Hz, 4 Hz, 5 Hz). Tactile perception thresholds, pain thresholds and summation pain thresholds were recorded. Temporal summation of pain could be elicited by stimulation of both skin, joint and muscle, although the influence of temporal summation appeared to be more pronounced for muscle stimulation. Muscle stimulation also required greater ultrasound intensity compared with joint and skin stimulation. Temporal summation could not be elicited by tactile, low-intensity stimulation. Focused ultrasound is a potent, noninvasive technique with which to investigate temporal summation from somatic structures. A number of factors may account for the higher intensities required to elicit pain in muscle and the increased rate of temporal summation. It is clear, however, that if temporal summation is more pronounced in muscle than other tissues then this may be an important factor contributing to pain in musculoskeletal syndromes.

Adult↗
PubMed2002

Ultrasound monitoring of temperature change during radiofrequency ablation: preliminary in-vivo results.

Radiofrequency (RF) ablation is an interstitial focal ablative therapy that can be used in a percutaneous fashion and permits in situ destruction of hepatic tumors. However, local tumor recurrence rates after RF ablative therapy are as high as 34% to 55%, which may be due in part to the inability to monitor accurately temperature profiles in the tissue being ablated, and to visualize the subsequent zone of necrosis (thermal lesion) formed. The goal of the work described in this paper was to investigate methods for the real-time and in vivo monitoring of the spatial distribution of heating and temperature elevation to achieve better control of the degree of tissue damage during RF ablation therapy. Temperature estimates are obtained using a cross-correlation algorithm applied to RF ultrasound (US) echo signal data acquired at discrete intervals during heating. These temperature maps were used to display the initial temperature rise and to continuously update a thermal map of the treated region. Temperature monitoring is currently performed using thermosensors on the prongs (tines) of the RF ablation probe. However, monitoring the spatial distribution of heating is necessary to control the degree of tissue damage produced.

Animals↗
PubMed2002

Energy and fat intake in obese and lean children at varying risk of obesity.

OBJECTIVE: This study compared lean children at high risk (HR) and low risk (LR) of obesity and obese children (OB) to assess the relationship between their energy (EI) and fat intake and adiposity. DESIGN: Cross-sectional study of energy and fat intake in children, using 7-day weighed intakes validated by doubly labelled water (DLW) energy expenditure. SUBJECTS: A total of 114 pre-pubertal children, 50 HR (mean+/-s.d., 6.7+/-0.6 y, 25.7+/-4.8 kg, 21.3+/-6.6% body fat), 50 LR (mean+/-s.d., 6.6+/-0.8 y, 23.6+/-3.7 kg, 18.9+/-5.7% body fat) and 14 OB (mean+/-s.d., 6.8+/-1.0 y, 37.7+/-5.3 kg, 34.8+/-5.6% body fat). MEASUREMENTS: Body fatness was measured using deuterium dilution, total energy expenditure (TEE) by DLW and dietary intake using 7-day weighed records. RESULTS: EI was 98% of TEE in LR children, 95% in HR children and 86% in OB children. Although EI was similar in each group (LR, 7.03+/-1.26 MJ/day; HR, 7.30+/-1.46 MJ/day; OB, 7.55+/-1.67 MJ/day), obese +/-4.6%; P<0.05). There was a significant linear trend towards increasing fat intake (percentage energy) with increasing risk of obesity (P<0.05). While HR children were heavier and fatter than LR children (P<0.05), their EI and fat intake were not significantly greater (HR, 73+/-17 g, 37.3+/-4.4%). Dietary fat intake (percentage energy) was weakly but significantly related to body fatness (r(2)=0.05, P=0.02) by step-wise regression. Since energy from fat was the only macronutrient that was a significant predictor of body fatness, results were therefore analysed using quartiles of fat intake (percentage energy) as cut-offs. When grouped in this way children with the lowest intakes were leaner than those with the highest intakes (19.5+/-7.5 vs 24.9+/-9.4% body fatness; P<0.05). There was a significant trend for increasing fatness as fat intake increased (P<0.05). CONCLUSION: Fat intake is related to body fatness in childhood.

Anthropometry↗
PubMed2002

Ossicular fixation caused by bone dust after saccus decompression surgery.

HYPOTHESIS: To highlight the clinical and histologic features of ossicular fixation produced by bone dust during mastoid surgery. BACKGROUND: Bone dust deposition in the middle ear may occur during temporal bone surgery, but the ossicular fixation that may result from it remains underreported. METHODS: A case is reported of delayed conductive hearing loss after saccus decompression surgery resulting from ossicular fixation by bone dust deposition. RESULTS: Six months after the initial surgery, the patient experienced a 45 dB conductive hearing loss. The findings on second-look tympanotomy were stapes fixation and round window niche occlusion by newly formed tissue. Histologic examination of the latter showed fibrosis and new bone formation in reaction to particles of bone dust. New bone formation is a frequent concomitant of fibrosis in the middle ear and is probably not a growth from the bone dust. CONCLUSION: The use of high-speed drilling of bone in temporal bone surgery carries the risk of bone dust particle deposition in the middle ear. Measures are discussed that can be used to prevent this complication.

Audiometry, Pure-Tone↗
PubMed2002

Investigation into the acceptability and effectiveness of a new contact slip in the management of Chlamydia trachomatis at a London genitourinary medicine clinic.

OBJECTIVES: To improve contact tracing for chlamydia. To determine (i) the acceptability to patients of using a contact slip that named chlamydia as the sexually transmissible infection that the contact may have been at risk of acquiring, and (ii) whether an augmented contact slip issued for chlamydia significantly increased the number of sexual partners attending for treatment. METHODS: For a 2 month period, all consecutive heterosexual patients diagnosed with chlamydia at the Mortimer Market Centre (MMC) were offered one or more coded contact slips (CS1) as per clinic protocol. During this time, and for 1 month afterwards, contacts presenting as a result of receiving these contact slips were recorded. This was compared to a subsequent 2 month period during which a contact slip naming chlamydia as the potential infection, with an information leaflet attached (CS2), was issued. Contacts attending as a result of receiving this augmented contact slip were recorded over a similar period. For both cohorts the number of patients refusing either contact slip, and contacts attending other GUM clinics, were recorded. RESULTS: 121 patients were diagnosed with chlamydia and were seen by a health adviser in period one and 130 patients were diagnosed and seen in period two. There was no significant difference detected between the acceptability of CS1 and CS2 (one refusal per cohort). There was a significant increase in the number of sexual contacts attending for treatment after being given CS2 (160 attending of 190 contact slips issued (84%, 95% CI 79 to 89)), compared to CS1 (48 attending of 144 contact slips issued (33%, 95% CI 26 to 43)). CONCLUSIONS: An infection specific contact slip was equally acceptable to patients as the standard contact slip, and it significantly increased the number of sexual contacts attending for treatment.

Adolescent↗
PubMed2001

Modulation of the effects of alcohol on driving-related psychomotor skills by chronic exposure to cannabis.

RATIONALE: Many previous studies have reported that alcohol and cannabis produce additive psychomotor effects in acute combination, but few have explicitly tested whether chronic exposure to cannabis, in the absence of acute administration, alters the effects of alcohol on psychomotor performance. OBJECTIVES: To test whether long-term cannabis use modulates the effects of alcohol on psychomotor skills and self-reported mood and sensation. METHODS: Regular cannabis users (minimum: daily use for at least 3 years) and infrequent users (maximum: once-monthly use for at most 3 years) were matched for sex, age, alcohol intake and other drug use (14 participants in each group). Participants received alcohol (females 0.35 g/kg; males 0.45 g/kg) and placebo drinks. By urinalysis, only regular users tested positive for metabolites of Delta(9)-tetrahydrocannabinol; breath alcohol levels were similar between groups. Participants were tested on a computerised tracking task that has been used to screen drugs for adverse effects on driving. The task involved tracking a moving target on a computer screen while simultaneously responding to occasional presentations of stimuli in the periphery of the screen. RESULTS: Tracking accuracy was similar for both groups after placebo, but alcohol caused a significant deterioration in performance among infrequent cannabis users relative to regular users. These changes were mirrored by significant changes in self-reported scores for dizziness, measured by visual analogue scales. Alcohol slowed reaction times, but not differentially between groups. CONCLUSIONS: For psychomotor skills relevant to driving, chronic cannabis use (in the absence of acute administration) does not potentiate the effects of alcohol. In fact, the superior tracking accuracy of regular users relative to infrequent users after alcohol, and their lower scores for dizziness, suggest that chronic cannabis use may instead confer cross-tolerance to specific effects of alcohol on behaviour.

Adult↗
PubMed2001

Mobilization of a Drosophila transposon in the Caenorhabditis elegans germ line.

Transposons have been enormously useful for genetic analysis in both Drosophila and bacteria. Mutagenic insertions constitute molecular tags that are used to rapidly clone the mutated gene. Such techniques would be especially advantageous in the nematode Caenorhabditis elegans, as the entire sequence of the genome has been determined. Several different types of endogenous transposons are present in C. elegans, and these can be mobilized in mutator strains (reviewed in ref. 1). Unfortunately, use of these native transposons for regulated transposition in C. elegans is limited. First, all strains contain multiple copies of these transposons and thus new insertions do not provide unique tags. Second, mutator strains tend to activate the transposition of several classes of transposons, so that the type of transposon associated with a particular mutation is not known. Here we demonstrate that the Drosophila mariner element Mos1 can be mobilized in C. elegans. First, efficient mobilization of Mos1 is possible in somatic cells. Second, heritable insertions of the transposon can be generated in the germ line. Third, genes that have been mutated by insertion can be rapidly identified using inverse polymerase chain reaction. Fourth, these insertions can subsequently be remobilized to generate deletion and frameshift mutations by imperfect excision.

Animals↗
PubMed2001

Lack of cross-species transmission of porcine endogenous retrovirus infection to nonhuman primate recipients of porcine cells, tissues, or organs.

BACKGROUND: Nonhuman primates (NHPs) have been widely used in different porcine xenograft procedures inevitably resulting in exposure to porcine endogenous retrovirus (PERV). Surveillance for PERV infection in these NHPs may provide information on the risks of cross-species transmission of PERV, particularly for recipients of vascularized organ xenografts for whom data from human clinical trials is unavailable. METHODS: We tested 21 Old World and 2 New World primates exposed to a variety of porcine xenografts for evidence of PERV infection. These NHPs included six baboon recipients of pig hearts, six bonnet macaque recipients of transgenic pig skin grafts, and nine rhesus macaque and two capuchin recipients of encapsulated pig islet cells. Serologic screening for PERV antibody was done by a validated Western blot assay, and molecular detection of PERV sequences in peripheral blood mononuclear cells (PBMCs) and plasma was performed using sensitive polymerase chain reaction and reverse transcriptase-polymerase chain reaction assays, respectively. Spleen and lymph node tissues available from six bonnet macaques and three rhesus macaques were also tested for PERV sequences. RESULTS: All plasma samples were negative for PERV RNA suggesting the absence of viremia in these xenografted animals. Similarly, PERV sequences were not detectable in any PBMC and tissue samples, arguing for the lack of latent infection of these compartments. In addition, all plasma samples were negative for PERV antibodies. CONCLUSION: These data suggest the absence of PERV infection in all 23 NHPs despite exposure to vascularized porcine organs or tissue xenografts and the use of immunosuppressive therapies in some animals. These findings suggest that PERV is not easily transmitted to these NHP species through these types of xenografts.

Animals↗
PubMed2001

Respiratory symptoms, lung function and cell surface markers in a group of hemp fiber processors.

BACKGROUND: Hemp dust exposure is associated with byssinosis and accelerated lung loss in longitudinal studies. The immunological changes associated with hemp dust exposure are less well understood. METHODS: We studied a small group of current male hemp processors with a mean age of 43 years. Questionnaire data, lung function, serial FEV(1) and blood were collected from all workers. RESULTS: In total, seven workers (64%) complained of at least one respiratory symptom (one with byssinosis). The mean percentage predicted FEV(1) was 91.5, FVC 97.7, PEF 92.1, and FEF(25-75) 79.5. Serial FEV(1) measurements in the two workers with work-related respiratory symptoms revealed a mean change in FEV(1) on the first working day of -12.9%. This contrasted with +6.25% on the last working day. Respective values for the two workers without work-related symptoms were -1.4 and +3.2%. CONCLUSIONS: Lung function changes and abnormalities in a profile of cell surface activation markers and antibodies were noted to relate to the presence of work-related respiratory symptoms, not seen in the control group.

Adult↗
PubMed2001

Does socioeconomic status predict course and outcome in patients with psychosis?

BACKGROUND: We examined the relationship between socioeconomic status (SES) and course and outcome of patients with psychosis. Two hypotheses were examined: a) patients with higher best-ever SES will have better course and outcome than those with lower best-ever SES, and b) patients with greater downward drift in SES will have poorer course and outcome than those with less downward drift. METHOD: Data were drawn from the baseline and 2-year follow-up assessments of the UK700 Case Management Trial of 708 patients with severe psychosis. The indicators of SES used were occupational status and educational achievement. Drift in SES was defined as change from best-ever occupation to occupation at baseline. RESULTS: For the baseline data highly significant differences were found between best-ever groups and negative symptoms (non-manual vs. unemployed--coef -10.5, p=0.000, 95% CIs 5.1-15.8), functioning (non-manual vs. unemployed--coef -0.6, p=0.000, 95% CIs 0.3 to -0.8) and unmet needs (manual vs. unemployed - coef 0.5, p=0.004, 95% CIs 0.2-0.9). No significant differences between best-ever groups were found for days in hospital, symptoms, perceived quality of life and dissatisfaction with services. Significant differences for clinical and social variables were found between drift and non-drift SES groups. There were no significant findings between educational groups and clinical and social variables. CONCLUSIONS: Best-ever occupation, but not educational qualifications, appeared to predict prognosis in patients with severe psychosis. Downward drift in occupational status did not result in poorer illness course and outcome.

Adult↗
PubMed2001

Nurses' knowledge of pain in the elderly.

The purpose of this study was to investigate nurses' knowledge of pain and pain management with respect to elderly persons. Registered nurses at several general hospitals and nursing homes were surveyed by questionnaire concerning their knowledge of pain management in the elderly. The findings indicated a significant knowledge deficit in this area. There were also significant differences in knowledge levels between general hospital nurses and those working in nursing homes. We conclude that more education about pain management in elderly patients is needed for nurses. This deficit needs to be addressed in both undergraduate nursing programs and hospital in-service courses. Presently, the majority of patients entering hospitals are aged 65 years and over. Hence, nurses in all areas of care, not just specifically those working in aged care facilities, need a sound knowledge of pain management of the elderly to facilitate compassionate and effective nursing care.

Aged↗
PubMed2001

MAP kinases.

Explore the source record for details and available documents.

Mitogen-Activated Protein Kinases↗
PubMed2001

Publishing trends in otorhinolaryngology from January 1997 to December 1999 in the UK.

In the last 10 years there have been many changes in otorhinolaryngology training and academic resources. The Calman reforms were introduced to our speciality in July 1996 and the last decade has also seen the number of professorial chairs in the UK rise from two to 12. One would therefore expect an increase in academic output, in terms of published works, despite the impediments generated by the Calman Training System. A search of eight leading English language otorhinolaryngology journals was carried out from January 1997 to December 1999 looking for articles with British authors. The results were compared with similar research carried out 10 years ago. There has been no major growth in the output of otorhinolaryngological publications from the UK in the last 10 years.

Bibliometrics↗
PubMed2001

Drugs of abuse in pregnancy.

Care for the drug-using pregnant woman is being increasingly recognized as part of the obstetrician's role. There is great potential for improvement in provision of services for this group of women, partly because traditionally our antenatal clinics have not been perceived as being conducive to disclosure regarding drug use, but also because hard data and, indeed, randomized controlled trials on the subject, are scarce.From the little evidence available, and from our own experience in this area, we have attempted to outline the main problems encountered in the antenatal, intrapartum and postnatal periods with each of the main drugs of abuse and the management thereof. It is important to note that we include cigarette smoking and alcohol, probably the most commonly used drugs in pregnancy, and recognize that the picture is wider than the stereotypical emaciated intravenous heroin addict. Where possible, evidence from trial data is included, but much of the what is quoted is descriptive from personal experience from ourselves and others working in the field.

Alcohol Drinking↗
PubMed2001

Knee joint mobilization reduces secondary mechanical hyperalgesia induced by capsaicin injection into the ankle joint.

Joint mobilization is a treatment approach commonly used by physical therapists for the management of a variety of painful conditions. However, the clinical effectiveness when compared to placebo and the neurophysiological mechanism of action are not known. The purpose of this study was to establish that application of a manual therapy technique will produce antihyperalgesia in an animal model of joint inflammation and that the antihyperalgesia produced by joint mobilization depends on the time of treatment application. Capsaicin (0.2%, 50 microl) was injected into the lateral aspect of the left ankle joint and mechanical withdrawal threshold assessed before and after capsaicin injection in Sprague-Dawley rats. Joint mobilization of the ipsilateral knee joint was performed 2 h after capsaicin injection for a total of 3 min, 9 min or 15 min under halothane anaesthesia. Control groups included animals that received halothane for the same time as the group that received joint mobilization and those whose limbs were held for the same duration as the mobilization (no halothane). Capsaicin resulted in a decreased mechanical withdrawal threshold by 2 h after injection that was maintained through 4 h. Both 9 and 15 min of mobilization, but not 3 min of mobilization, increased the withdrawal threshold to mechanical stimuli to baseline values when compared with control groups. The antihyperalgesic effect of joint mobilization lasted 30 min. Thus, joint mobilization (9 or 15 min duration) produces a significant reversal of secondary mechanical hyperalgesia induced by intra-articular injection of capsaicin.

Animals↗
PubMed2001

Cervical mobilisation: concurrent effects on pain, sympathetic nervous system activity and motor activity.

Recent findings that spinal manual therapy (SMT) produces concurrent hypoalgesic and sympathoexcitatory effects have led to the proposal that SMT may exert its initial effects by activating descending inhibitory pathways from the dorsal periaqueductal gray area of the midbrain (dPAG). In addition to hypoalgesic and sympathoexcitatory effects, stimulation of the dPAG in animals has been shown to have a facilitatory effect on motor activity. This study sought to further investigate the proposal regarding SMT and the PAG by including a test of motor function in addition to the variables previously investigated. Using a condition randomised, placebo-controlled, double blind, repeated measures design, 30 subjects with mid to lower cervical spine pain of insidious onset participated in the study. The results indicated that the cervical mobilisation technique produced a hypoalgesic effect as revealed by increased pressure pain thresholds on the side of treatment (P=0.0001) and decreased resting visual analogue scale scores (P=0.049). The treatment technique also produced a sympathoexcitatory effect with an increase in skin conductance (P<0.002) and a decrease in skin temperature (P=<0.02). There was a decrease in superficial neck flexor muscle activity (P<0.0002) at the lower levels of a staged cranio-cervical flexion test. This could imply facilitation of the deep neck flexor muscles with a decreased need for co-activation of the superficial neck flexors. The combination of all findings would support the proposal that SMT may, at least initially, exert part of its influence via activation of the PAG.

Adult↗