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Biomedical subjects

B H Smith

Publications and source records attributed to B H Smith.

At least 19 recordsLinked to original sources
PubMed2006

Continuous positive airways pressure for obstructive sleep apnoea in adults.

BACKGROUND: Obstructive sleep apnoea is the periodic reduction (hypopnoea) or cessation (apnoea) of breathing due to narrowing or occlusion of the upper airway during sleep. The main symptom is daytime sleepiness and it has been suggested it is linked to premature death, hypertension, ischaemic heart disease, stroke and road traffic accidents. OBJECTIVES: The main treatment for sleep apnoea is with the use of continuous positive airways pressure (CPAP), which requires a flow generator and mask. These are used at night to prevent apnoea, hypoxia and sleep disturbance. The objective was to assess the effects of CPAP in the treatment of obstructive sleep apnoea in adults. SEARCH STRATEGY: We searched the Cochrane Airways Group Trials Register and reference lists of articles. We consulted experts in the field. Searches were current to July 2005. SELECTION CRITERIA: We included randomised trials comparing nocturnal CPAP with an inactive control or oral appliances in adults with obstructive sleep apnoea (an apnoea and hypopnoea index greater than five per hour). Trials had a minimum intervention period of two weeks. DATA COLLECTION AND ANALYSIS: Trial quality was assessed and two review authors extracted data independently. Study authors were contacted for missing information. Parallel and crossover group trials were analysed separately. MAIN RESULTS: Thirty-six trials involving 1718 people met the inclusion criteria. Study quality was mixed. Compared with control, CPAP showed significant improvements in certain objective and subjective sleepiness, measures of quality of life and cognitive function (parallel-group studies: Epworth sleepiness scale (ESS) -3.83 units, 95% CI -4.57 to -3.09; crossover studies: ESS -1.84 units, 95% CI -2.57 to -1.11). Twenty-four hour systolic and diastolic blood pressures were lower with CPAP compared with control (parallel-group trials). Compared with oral appliances, CPAP significantly reduced the apnoea and hypopnoea index (crossover studies: -7.97 events/hr, 95% CI -9.56 to -6.38) and improved sleep efficiency (crossover studies: 2.31%, 95% CI 0.02 to 4.6) and minimum oxygen saturation (4.14%, 95% CI 3.25 to 5.03). Responders to both treatments expressed a strong preference for the oral appliance. However, participants were more likely to withdraw on OA than on CPAP therapy. AUTHORS' CONCLUSIONS: CPAP is effective in reducing symptoms of sleepiness and improving quality of life measures in people with moderate and severe obstructive sleep apnoea (OSA). It is more effective than oral appliances in reducing respiratory disturbances in these people but subjective outcomes are more equivocal. Certain people tend to prefer oral appliances to CPAP where both are effective. This could be because they offer a more convenient way of controlling OSA. Short-term data indicate that CPAP leads to lower blood pressure than control. Long-term data are required for all outcomes in order to determine whether the initial benefits seen in short-term clinical trials persist.

Adult↗
PubMed2003

Protein S declines during winter respiratory infections.

There is an increase in cardiovascular and cerebrovascular morbidity and mortality in the older adult population during the winter that could be related to prothrombotic changes caused by seasonal effects or acute respiratory tract infections. Therefore, a prospective cohort study was conducted to assess the effect of acute winter respiratory infection on hemostatic parameters including complement 4b-binding protein (C4-BP), functional protein S, total protein S, free protein S, and the inflammatory marker, interleukin-6 (IL-6), in younger and older adults. The changes in the levels of hemostatic and inflammatory markers during winter respiratory infections in the younger and older adults were compared with matched, non-infected controls. In younger and older adults (combined), total protein S increased from 83% [95% confidence interval (CI); 77-88] to 98% (95% CI; 91-106, P < 0.001) while free protein S decreased from 100% (95% CI; 95-105) to 70% (95% CI; 66-75, P < 0.001). There were no significant changes in C4-BP (P = 0.622), functional protein S (P = 0.061) or IL-6 (P = 0.651) from baseline. In a multivariate analysis, only total protein S and free protein S showed significant association with seasonal change after adjusting for the effect of infection. The estimated effect of season on total protein S was 15 +/- 4%, P < 0.001 and on free protein S was -27 +/- 3%, P < 0.001. After adjusting for seasonal effect, only functional protein S showed a significant association with infection, with the estimated effect of -17 +/- 5%, P < 0.001. The results in the younger and older adults were similar to those in the combined groups. Seasonal and infection-related changes in hemostatic parameters including an increase in fibrinogen and a decrease in free protein S, observed in this study, may contribute to thrombotic risk and excess vascular disease morbidity and mortality in older populations in the winter season.

Age Factors↗
PubMed2003

Chronic pain and the use of conventional and alternative therapy.

BACKGROUND: Chronic pain is a common problem affecting about half of the general population. This has implications for the utilization of both conventional and alternative health services. OBJECTIVES: The aim of this study was to determine the use of conventional and alternative practitioners and medicines amongst individuals with chronic pain in the community. METHODS: A total of 2422 individuals from a previous population-based survey in the Grampian region of the UK, who agreed to participate in further research, were sent a postal questionnaire. The questionnaire enquired about the presence, type and severity of chronic pain, socio-demographic details, consultations with conventional and alternative practitioners, and the consumption of conventional and alternative medicines. The main outcome measures were the number and frequency of self-reported consultations with GPs, hospital specialists, physical therapists and alternative therapists, and the consumption of prescription, non-prescription and alternative medicines amongst those with chronic pain. RESULTS: Of the 840 individuals reporting chronic pain, 67.2% had seen their GP, 34.0% a hospital specialist, 25.9% a physical therapist and 18.2% an alternative therapist in the preceding year. Prescription medicines had been taken by 58.4%, non-prescription medicines by 57.4% and alternative medicines by 15.7% of individuals with chronic pain. The majority (67.0%) of individuals with chronic pain who sought alternative health care did so in conjunction with conventional health care. Differences in consultations with practitioners and consumption of medicines were found by age, sex, socio-economic status, site of pain and severity of pain. CONCLUSIONS: Individuals with chronic pain consult their GP about their pain more than other practitioners and use conventional medicines more frequently than alternative medicines. Alternative health care is used most commonly in addition to conventional health care, although a small number of individuals with chronic pain use alternative care exclusively. The use of alternative health care amongst those with chronic pain is higher than previously estimated and suggests that the use of these services may be increasing amongst those with chronic pain.

Adult↗
PubMed2003

Survey for coccidia and haemosporidia in the lesser prairie-chicken (Tympanuchus pallidicinctus) from New Mexico with description of a new Eimeria species.

Blood films and fecal samples of the lesser prairie-chicken (Tympanuchus pallidicinctus) were examined for parasites when we surveyed specimens captured during a radio-tracking study conducted in Chaves County, New Mexico (USA). All birds were captured on the Caprock Wildlife Habitat Management Area, administered by the Bureau of Land Management. Samples were collected in late March, April, and early May 1998-2000. Oocysts were detected in five of 64 (8%) birds sampled and, upon sporulation, were determined to be an Eimeria species. This is the first eimerian reported from the lesser prairie-chicken and is described here as a new species. Sporulated oocysts are ellipsoidal, 27.1 x 22.7 (22-32 x 18-26) microns, with micropyle absent, but oocyst residuum and polar granule present. Sporocysts are ovoidal, 11.9 x 7.8 (10-14 x 6-10); a Stieda body, and sporocyst residuum are present, as is a small, indistinct substieda body. Inspection of blood smears revealed four cases of Plasmodium infection of 32 (13%) individuals sampled. The characteristics of this plasmodiid are consistent with the description of Plasmodium (Giovannolaia) pedioecetii, previously found in T. pallidicinctus (Stabler, 1978).

Animals↗
PubMed2002

The course of chronic pain in the community: results of a 4-year follow-up study.

Little is known about the course of chronic pain in the community. Such information is needed for the prevention and management of chronic pain. We undertook a 4-year follow-up study of 2184 individuals living in Grampian, UK to describe patterns and predictors of change in chronic pain over time. In October 2000, participants completed a postal questionnaire including case definition questions, the chronic pain grade questionnaire, the SF-36 and socio-demographic questions. Information from this questionnaire was compared to information collected from a similar questionnaire in 1996. A response rate of 83% was achieved for the follow-up study. The overall prevalence of chronic pain (pain or discomfort present either all the time or on and off for 3 months or longer) increased from 45.5% at baseline to 53.8% at follow-up. Seventy-nine percent of those with chronic pain at baseline still had it at follow-up. The average annual incidence was 8.3% and the average annual recovery rate was 5.4%. Individuals in the study samples who are in lowest quartile of SF-36 domains--physical functioning, social functioning and bodily pain at baseline--were more likely to develop chronic pain at follow-up, and respondents who were retired were less likely to develop chronic pain. Individuals in the study samples in the lowest quartile of SF-36 domains, bodily pain and general health at baseline, were less likely to recover from their chronic pain, as were those aged 45-74 compared with those aged 25-34. We concluded that chronic pain is a common, persistent problem in the community with relatively high incidence and low recovery rates. The lack of association between onset or recovery from chronic pain and most traditional socio-demographic factors, highlights the need to broaden the range of factors included in studies of chronic pain aetiology.

Adult↗
PubMed2001

Peritoneal implantation of macroencapsulated porcine pancreatic islets in diabetic rats ameliorates severe hyperglycemia and prevents retraction and simplification of hippocampal dendrites.

The hippocampus of rats with uncontrolled insulin-dependent diabetes undergoes retraction and simplification of apical dendrites of the CA3 pyramidal neurons and synaptic rearrangements within mossy fiber terminals that could alter hippocampal connectivity and function. The intraperitoneal implantation of hydrophilic agarose macrobeads containing porcine islets for 17 days in rats with streptozotocin-induced diabetes results in normalization of body weight gain, significant control of hyperglycemia and prevention of hippocampal dendritic remodeling, and therefore, provides an effective therapeutic option.

Animals↗
PubMed2001

Olfactory-based discrimination learning in the moth, Manduca sexta.

Moths possess highly tuned olfactory capabilities, which can detect very low concentrations of pheromonal odorants. Much is known about the structure and function of the moth olfactory system with respect to detection of pheromones. However, we lack an understanding of the broader olfactory system, in particular, to what degree are moths capable of detecting and discriminating odorants that are not components of pheromone blends. Here we describe a methodology used to investigate the discriminability of nonpheromonal odors in moths. In a series of experiments we show that the moth Manduca sexta can (1) discriminate a number of different odors but (2) that methyl jasmonate, neither readily conditions to a food reward nor is it readily discriminated from another odor. The lack of a response to methyl jasmonate may be related to its role in host plant defense. This work provides a basis for future mapping of physiological and pharmacological studies of nonpheromonal coding in insects onto learned behavioral responses to those odorants.

Journal Article↗
PubMed2001

Factor structure and criterion validity of secondary school teacher ratings of ADHD and ODD.

Attention-Deficit Hyperactivity Disorder (ADHD) is currently viewed as a heterogeneous disorder with two factors: inattention and impulsivity-hyperactivity. This conceptualization of ADHD is based primarily on research with children or samples that mix children and adolescents. To examine if the 2-factor ADHD model is appropriate for adolescents and if the ADHD factors are distinct from Oppositional Defiant Disorder (ODD) in adolescents, teacher rating data were collected for 2 samples of adolescents. The results of a confirmatory factor analysis supported the convergent and divergent validity of a model with separate but correlated factors for inattention, impulsivity-hyperactivity, and defiant behavior. Further evidence of construct validity was found when factor scores were examined relative to the criterion variables of academic performance and rule-breaking behavior. The results support the utility of teacher ratings of ADHD and ODD in the assessment of adolescents, and the applicability of the DSM-IV conceptualization of these disorders to adolescents.

Adolescent↗
PubMed2001

Quantitative trait loci associated with reversal learning and latent inhibition in honeybees (Apis mellifera).

A study was conducted to identify quantitative trait loci (QTLs) that affect learning in honeybees. Two F1 supersister queens were produced from a cross between two established lines that had been selected for differences in the speed at which they reverse a learned discrimination between odors. Different families of haploid drones from two of these F1 queens were evaluated for two kinds of learning performance--reversal learning and latent inhibition--which previously showed correlated selection responses. Random amplified polymorphic DNA markers were scored from recombinant, haploid drone progeny that showed extreme manifestations of learning performance. Composite interval mapping procedures identified two QTLs for reversal learning (lrn2 and lrn3: LOD, 2.45 and 2.75, respectively) and one major QTL for latent inhibition (lrn1: LOD, 6.15). The QTL for latent inhibition did not map to either of the linkage groups that were associated with reversal learning. Identification of specific genes responsible for these kinds of QTL associations will open up new windows for better understanding of genes involved in learning and memory.

Animals↗
PubMed2001

Dose-response effects of methylphenidate on ecologically valid measures of academic performance and classroom behavior in adolescents with ADHD.

The effects of methylphenidate on the academic performance and classroom behavior of 45 adolescents with attention deficit hyperactivity disorder were studied. During a 6-week, placebo-controlled medication assessment in the context of a summer treatment program, participants received a double-blind, crossover trial of 3 doses of methylphenidate. Dependent measures included note-taking quality, quiz and worksheet scores, written language usage and productivity, teacher ratings, on-task and disruptive behavior, and homework completion. Group data showed positive effects of methylphenidate on academic measures; however, the greatest benefit came with the lowest dose. Although additional benefit did occur for some participants with higher doses, the largest increment of change usually occurred between the placebo and 10-mg dose. Many adolescents did not experience added benefit with increased dosages, and in some cases they experienced deterioration. Guidelines for assessment of medication effects are discussed.

Adolescent↗
PubMed2001

The Level of Expressed Need--a measure of help-seeking behaviour for chronic pain in the community.

Chronic pain is a common and disabling condition, with a high impact on health and the health services in the community. The extent of help-seeking behaviour and factors that influence this are complex, but poorly understood. A simple, valid measure of help-seeking behaviour would be useful for community-based research, with a view to developing and evaluating interventions. The aims of the study were to test a hierarchical scale designed to measure help-seeking behaviour in chronic pain in postal surveys of the community, and to explore factors associated with responses. As part of a community survey of chronic pain, we developed the Level of Expressed Need (LEN) scale, based on questions about the use of treatment and professional advice for chronic pain. We compared this scale with two measures of chronic pain severity--the Chronic Pain Grade (CPG), and the Glasgow Pain Questionnaire (GPQ)--and analyzed associations with the SF36 general health questionnaire and demographic variables. Of 3605 respondents (corrected response rate 82%), 1817 reported chronic pain. Of these, 17% were at the mildest and 28% at the severest LEN. There were strong correlations with both the CPG (r=0.48) and the GPQ (r=0.55). There were, however, many important disparities in responses to these measures. Several other factors were independently associated with a high LEN in chronic pain: female gender, lower educational level, and physical, mental, pain and general health dimensions of the SF36 questionnaire. The LEN is a useful tool for measuring the help-seeking response to chronic pain in the general population. The findings confirm that this response is influenced by clinical and demographic factors in addition to the severity of the pain. Further development work will strengthen the instrument to explore these.

Adult↗
PubMed2001

A randomized controlled trial of direct access for laparoscopic sterilization.

OBJECTIVES: The aim of this study was to establish and evaluate a direct access service for laparoscopic sterilization. METHODS: A pragmatic randomized controlled trial was carried out on a total of 232 women referred to Aberdeen Royal Infirmary for sterilization between 1 June 1996 and 31 March 1997, from 57 general practices around Aberdeen, Scotland, comprising 75 from general practices that had received criteria for direct access, and 157 from control practices. The main outcome measures were: patients' waiting times to appointments and operation, satisfaction, short-term regret, operative complications and costs; conjoint analysis of patient preferences; GPs' adherence to referral criteria; GP and gynaecologist satisfaction; and NHS costs. RESULTS: Analysis was by intention to treat. There were no inappropriate direct referrals. Waiting time was lower in the intervention group, but there were more visits post-operatively to the GP. Patient and doctor satisfaction was equally high in both groups. There was no difference in operative complication rate, nor in total cost to patients or to the NHS. GPs and gynaecologists strongly supported direct access, but women preferred to meet both a gynaecologist and a GP before sterilization (routine referral). Other attributes of care important to patients included written information, although waiting time was not important. Of all women referred for sterilization during the study period, only 31% were suitable for direct referral. CONCLUSIONS: Patients preferred routine referral, and there were no differences in patient costs or satisfaction. There was, however, strong medical support for direct referral. Restrictive direct referral criteria may limit the uptake. These findings are important for future planning of direct referral services. Important methodological lessons were also learnt about the conduct of trials involving the primary-secondary care interface.

Adult↗
PubMed2001

The impact of chronic pain in the community.

BACKGROUND: Chronic pain is known to be very common in the community. Less is known about the epidemiology of more significant or severe chronic pain. The impact of chronic pain in the community, in terms of general health, employment and interference with daily activity, has not been quantified. OBJECTIVES: The aim of this study was to describe the prevalence and distribution in the community of chronic pain defined as 'significant' and 'severe', and to explore the impact of chronic pain on health and activity. METHODS: A questionnaire survey was carried out of a sample drawn from the general population in the Grampian region of SCOTLAND: Questionnaires were sent to a random sample of 4611 individuals aged 25 years and over, stratified for age and gender, selected from the practice lists of 29 general practices (total practice population 136,383). The study instrument included a case definition questionnaire, from which were identified individuals with 'any chronic pain' (pain of at least 3 months duration). The instrument also included a level of expressed need questionnaire and the chronic pain grade questionnaire, from which were derived definitions for 'significant chronic pain' (based on the reported need for treatment and professional advice) and 'severe chronic pain' (based on reported intensity and pain-related disability). The SF-36 general health questionnaire and demographic questions were also included. RESULTS: Of the sample, 14.1% reported 'significant chronic pain', and this was more prevalent among women and older age groups. A total of 6.3% reported 'severe chronic pain', and this was more common in older age groups. On multiple logistic regression modelling, female gender, housing tenure, employment category and educational attainment were found to be independently associated with both 'significant' and 'severe' chronic pain. The presence of 'any', 'significant' and 'severe' chronic pain had progressively more marked adverse associations with employment, interference with daily activities and all measured dimensions of general health. CONCLUSIONS: Comparison of the epidemiology of 'significant chronic pain' and 'severe chronic pain' with 'any chronic pain' allows an understanding of the more clinically important end of the chronic pain spectrum. These results support the suggestion that chronic pain is multidimensional, both in its aetiology and in its effects, particularly at this end of the spectrum. This must be addressed in management and in further research.

Activities of Daily Living↗
PubMed2001

The generalization of an olfactory-based conditioned response reveals unique but overlapping odour representations in the moth Manduca sexta.

Most highly derived olfactory systems, such as the insect antennal lobe, discriminate among a wide array of monomolecular odourants and blends of odourants. Given the relatively limited number of neurons used to code these odours, this ability implies that neural representations for odours overlap in a cross-fiber coding scheme. Here we use the generalization of a conditioned feeding response in the sphinx moth, Manduca sexta, to quantify three geometry-based dimensions of odour space in which monomolecular odours may be assessed. In a series of experiments we show that generalization of a conditioned response from one monomolecular odour to another is a function of differences in length and shape of the carbon chain as well as the functional group on the molecule. When moths were conditioned to 2-hexanone or 1-decanol and tested with a number of alcohols and ketones, we found that the generalization of the conditioned response decreased as a function of the chain length and functional group. In contrast, when conditioned to 1-hexanol, moths failed to distinguish alcohols from ketones of the same chain length. In all of these cases, chain length did not interact with functional group, thus indicating the independence of these dimensions. Differential conditioning of alcohols and of alcohols and ketones revealed interaction of excitatory and inhibitory generalization gradients within an odour 'dimension'. When odourants were sufficiently distinct, the peak of the generalization gradient was shifted away from the conditioning odour and in an opposite direction from the unreinforced odour. Altogether, these data substantiate the claim that these molecular characteristics are relevant coding dimensions in the moth olfactory system. These data are consistent with a cross-fiber coding scheme in which odours are coded by spatio-temporally overlapping sets of neurons, both in the periphery and in the antennal lobes.

Alcohols↗
PubMed2001

Prothrombotic changes in hemostatic parameters and C-reactive protein in the elderly with winter acute respiratory tract infections.

Mortality rates attributable to cerebrovascular and ischemic heart disease increase among older adults during the winter. Prothrombotic changes in the hemostatic system related to seasonal factors, such as ambient temperature changes, and winter acute respiratory tract infections, may contribute to this excess seasonal mortality. A prospective nested case-control study was conducted to assess the impact of winter acute respiratory tract infections on fibrinogen, factor VII, factor VIIa, D-dimer, prothrombin fragment 1.2, PAI-1, soluble P-selectin and C-reactive protein (CRP) in older adults. The change in laboratory parameters from baseline (fall) to the time of infection in both middle-aged and elderly individuals was compared with matched non-infected controls. In older adult participants with winter acute respiratory tract infections, significant increases occurred in fibrinogen and C-reactive protein, but not in any other markers. The mean fibrinogen increased 1.52 g/L (38%) and the mean CRP increased 37 mg/L (370%) over baseline (both p <0.001). In a multivariate analysis, both infection and season were associated with the increase in fibrinogen, but only infection was associated with the CRP increase. Old age magnified the increase in CRP but not in fibrinogen. Winter acute respiratory tract infections induce an exaggerated inflammatory response in older adults. The associated increase in fibrinogen, an independent risk factor for ischemic heart disease, may be partly responsible for the excess winter vascular mortality.

Acute Disease↗