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Biomedical subjects

A Young

Publications and source records attributed to A Young.

At least 73 records · Page 4Linked to original sources
PubMed2001

Parents' Experience of Universal Neonatal Hearing Screening: A Critical Review of the Literature and Its Implications for the Implementation of New UNHS Programs.

This article presents a critical review of literature reporting the effects on parents of universal neonatal hearing screening (UNHS). It explores how parents experience the process and outcome of screening and in particular focuses on debates surrounding false positive identification, the evidence base for maternal/parental anxiety, consent, and family cultural/sociodemographic influences on the effective implementation of UNHS programs. These issues are then set within the context of events in the United Kingdom, where the Department of Health has recently initiated a program to pilot the introduction of universal neonatal hearing screening at 20 sites in England.

Journal Article↗
PubMed2001

Fourteen-year follow-up of speech/language-impaired and control children: psychiatric outcome.

OBJECTIVE: To examine the association between early childhood speech and language disorders and young adult psychiatric disorders. METHOD: In a longitudinal community study conducted in the Ottawa-Carleton region of Ontario, Canada, interviewers administered structured psychiatric interviews to age 19 participants who were originally identified as speech-impaired only, language-impaired, or nonimpaired at age 5. The first stage of the study took place in 1982 when participants were 5 years old, and the latest stage of the study took place between 1995 and 1997 when participants had a mean age of 19 years. This report examines the association between early childhood speech/language status and young adult psychiatric outcome. RESULTS: Children with early language impairment had significantly higher rates of anxiety disorder in young adulthood compared with nonimpaired children. The majority of participants with anxiety disorders had a diagnosis of social phobia. Trends were found toward associations between language impairment and overall and antisocial personality disorder rates. Males from the language-impaired group had significantly higher rates of antisocial personality disorder compared with males from the control group. Age of onset and comorbidity did not differ by speech/language status. The majority of participants with a disorder had more than one. CONCLUSIONS: Results support the association between early childhood speech and language functioning and young adult psychiatric disorder over a 14-year period. This association underscores the importance of effective and early interventions.

Adult↗
PubMed2001

Increased expression of transforming growth factor-beta after cerebral ischemia in the baboon: an endogenous marker of neuronal stress?

There has been an increasing interest in recent years in the evaluation of the neuronal and glial responses to ischemic insult. Some cytokines, including transforming growth factor-beta (TGF-beta), that are overexpressed after experimental stroke in rodents are thought to be implicated in the neuronal processes that lead to necrosis. Thus, such cytokines could predict tissue fate after stroke in humans, although data are currently sparse for gyrencephalic species. The current study addressed the expression pattern of TGF-beta1 in a nonhuman primate model of middle cerebral artery occlusion. Focal permanent ischemia was induced for 1 or 7 days in 6 baboons and the following investigations were undertaken: cerebral oxygen metabolism (CMRO2) positron emission tomography studies, magnetic resonance imaging, postmortem histology, and reverse transcription-polymerase chain reaction. The aim of the current study was to correlate the expression of TGF-beta1 to the underlying metabolic and histologic state of the threatened cerebral parenchyma. The authors evidenced increased TGF-beta1 mRNA levels (up to 25-fold) in those regions displaying a moderate (20% to 49%) reduction in CMRO2. The current findings suggest that the greatly enhanced expression of TGF-beta1 in the penumbral zones that surround tissue destined to infarction may represent a robust index of potentially salvageable brain. The current investigation, in the nonhuman primate, strengthens the authors' hypothesis, derived from rodent models, that TGF-beta1 may be involved in the physiopathology of human stroke.

Animals↗
PubMed2001

A variable inertial system for measuring the contractile properties of human muscle.

PURPOSE: A flywheel system of variable inertia is described for inferring the mechanical properties of human muscle during a single explosive movement. METHODS: The system consists of a lightweight aluminum disk mounted on a shaft onto which a driving cog is mounted. The inertia of the system can be varied from 0.024 to 0.69 kg.m(2) by attaching semicircular steel plates to the disk. A rotary encoder detects displacement of the wheel with a resolution of 1 degrees. Digital signals from the encoder are collected using an A/D converter interfaced to a PC. The data are then processed for the calculation of torque, velocity, power, work done, and acceleration. The mechanical properties of the muscles employed are inferred from calculations of flywheel displacement, time, and force. In addition, a pretension release mechanism can be incorporated into the system to allow isometric force to be developed before movement. This can increase power generation at the low inertias where the time of contraction is typically less than 200 ms. Seven subjects were test-retested using the device. Measures of both average and peak power were made. RESULTS: When mounted in the apparatus described by Bassey and Short, the maximum values for peak and average power were on average 965 +/- 103 and 448 +/- 47 W, respectively. Upon retesting, these results were found to be reliable (cv = 3.3% and 3.0%, respectively). CONCLUSIONS: The inertial system described has been shown to have validity in reproducibility and provided a suitable method of determining a number of muscle output properties during short-term single exertions. This tool could prove useful in a research or clinical setting and may also prove useful as a training device as it negates the need for a strain gauge or goniometer attachment.

Acceleration↗
PubMed2001

Amylin and bone metabolism in streptozotocin-induced diabetic rats.

Amylin (AMY) is a 37 amino acid peptide cosecreted with insulin (INS) by pancreatic beta-cells and absent in type 1 diabetes, a condition frequently associated with osteopenia. AMY binds to calcitonin receptors, lowers plasma calcium concentration, inhibits osteoclast activity, and stimulates osteoblasts. In the present study, we examined the effects of AMY replacement on bone loss in a streptozotocin (STZ)-induced rodent model type 1 diabetes. Of 50 male Wistar rats studied, 40 were made diabetic with intraperitoneal STZ (50 mg/kg; plasma glucose concentrations > 11 mM within 5 days). Ten nondiabetic control (CONT) rats received citrate buffer without STZ. Diabetic rats were divided into four groups (n = 10/group) and injected subcutaneously with rat AMY (45 mg/kg), INS (12 U/kg), both (same doses), or saline (STZ; diabetic controls) once per day. After 40 days of treatment and five 24-h periods of urine collection for deoxypyridinoline (DPD), the animals were killed, blood was sampled, and femurs were removed. The left femur was tested for mechanical resistance (three-point bending). The right femur was tested for total, diaphyseal (cortical bone), and metaphyseal (trabecular bone) bone densities using dual-energy X-ray absorptiometry (DXA). Bone was ashed to determine total bone mineral (calcium) content. None of the treatments had any significant effect on femoral length and diameter. Untreated diabetic rats (STZ; 145+/-7N) had lower bone strength than did nondiabetic CONT (164+/-38; p < 0.05). Total bone mineral density (BMD; g/cm2) was significantly lower in STZ (0. 2523+/-0.0076) than in CONT (0.2826+/-0.0055), as were metaphyseal and diaphyseal densities. Diabetic rats treated with AMY, INS, or both had bone strengths and bone densities that were indistinguishable from those in nondiabetic CONT. Changes in bone mineral content paralleled those for total BMD (T-BMD). Plasma osteocalcin (OC) concentration, a marker for osteoblastic activity, was markedly lower in untreated diabetic rats (7. 6+/-0.9 ng/ml); p < 0.05) than in nondiabetic CONT (29.8+/-1.7; p < 0.05) or than in AMY (20.1+/-0.7; p < 0.05). Urinary DPD excretion, a marker for bone resorption, was similar in untreated and AMY-treated diabetic rats (35.0+/-3.1 vs. 35.1+/-4.4 nmol/mmol creatinine), intermediate in rats treated with INS (49.9+/-2.7), and normalized in diabetic rats treated with both agents (58.8+/-8.9 vs. 63.2+/-4.5 in CONT). Thus, in our STZ rat model of diabetic osteopenia, addition of AMY improved bone indices apparently by both inhibiting resorption and stimulating bone formation.

Amyloid↗
PubMed2001

GREAT-ER: a new tool for management and risk assessment of chemicals in river basins. Contribution to GREAT-ER #10.

The GREAT-ER (Geo-referenced Regional Exposure Assessment Tool for European Rivers) project team has developed and validated an accurate aquatic chemical exposure prediction tool for use within environmental risk assessment schemes. The software system GREAT-ER 1.0 calculates the distribution of predicted environmental concentrations (PECs) of consumer chemicals in surface waters, for individual river stretches as well as for entire catchments. The system uses an ARC/INFO-ArcView (ESRI) based Geographical Information System (GIS) for data storage and visualization, combined with simple mathematical models for prediction of chemical fate. At present, the system contains information for four catchments in Yorkshire, one catchment in Italy, and two in Germany, while other river basins are being added. Great-ER 1.0 has been validated by comparing simulations with the results of an extensive monitoring campaign for two 'down-the-drain' chemicals, i.e. the detergent ingredients boron and Linear Alkylbenzene Sulphonate (LAS). GREAT-ER 1.0 is currently being expanded with models for the terrestrial (diffuse input), air and estaurine compartments.

Environmental Monitoring↗
PubMed2001

Forearm blood flow and local responses to peptide vasodilators: a novel pharmacodynamic measure in the phase I trial of antagonist G, a neuropeptide growth factor antagonist.

PURPOSE: Arg-D-Trp-NmePhe-D-Trp-Leu-Met-NH(2) (Antagonist G), a substance P (SP 6-11) analogue, inhibits mitogenesis stimulated by a broad spectrum of neuropeptides and has demonstrated antitumor activity in vitro and in vivo with IC(50) concentrations of 10-20 microM in small cell lung cancer and other cell lines. Because neuropeptides are part of complex neurohumoral pathways, we have sought to develop novel pharmacodynamic approaches as part of the early clinical development of this potential anticancer drug. EXPERIMENTAL DESIGN: A Phase I trial was performed in two stages. In stage 1, Antagonist G was administered at 3- week intervals using an accelerated dose-escalation strategy until the target maximum plasma concentration (C(max)) of 10 microM was achieved. In stage 2, dose intensity was increased to weekly, and the inhibitory effect of i.v. Antagonist G was assessed by forearm blood flow (FBF) using SP as a vasodilator, as measured by venous plethysmography. RESULTS: In stage 1, dose was escalated from 2 to 300 mg/m(2) in 12 dose levels using only 15 patients. In stage 2, nine patients were entered at three dose levels (300, 350, and 400 mg/m(2)) and a C(max) of 45 microM was achieved. Facial flushing was the only consistent toxicity but was not dose limiting. FBF studies demonstrated that Antagonist G consistently inhibited the vasodilatory effects of SP (mean, 62 +/- 2% inhibition). CONCLUSIONS: Antagonist G can be safely administered up to 400 mg/m(2), achieving C(max)s >20 microM by weekly 6-h i.v. infusion. FBF studies in patients demonstrated that Antagonist G inhibits SP vasodilatory effects in vivo at these doses in the absence of dose-limiting toxicity.

Adult↗
PubMed2000

Perception of emotions in anxious and learning disabled children.

This study examined differences in the ability to perceive others' emotions in anxious and learning disabled children, as these differences may contribute to these children's unique socio-emotional difficulties and therapeutic needs. Forty-six children ages 8 to 12 with either anxiety disorders (ANX), language-based learning disabilities (LD), both conditions, or neither condition (clinical controls) were compared on the DANVA, a standardized measure of auditory and visual perception of emotion. Group results were then compared to normative data. Using multivariate analyses, significant group differences were found on the auditory portion of the DANVA but not on the visual portion. LD and comorbid children scored lower on several auditory stimuli, especially when presented at low emotional intensity, while ANX and comorbid children showed high accuracy for auditory sadness. Comorbid children also had lower auditory DANVA scores than the normative sample. No interactive effects between ANX and LD were found. ANX and LD each appear to have distinct effects on the auditory perception of others' emotions. Children with both conditions show both effects and differ from normal children in this domain. Replication using larger samples is required.

Anxiety Disorders↗
PubMed2000

Duration of action of inhaled vs. Intravenous beta(2)-adrenoceptor agonists in an anaesthetized guinea-pig model.

We compared the duration of action of the short-acting alpha(2)-adrenoceptor agonist salbutamol and the long-acting alpha(2)-adrenoceptor agonists salmeterol and formoterol when administered iv or by inhalation in a histamine-induced bronchoconstriction model in the guinea-pig. Following aerosol dosing, maximal bronchoprotector effects were seen for salbutamol, salmeterol and formoterol at concentrations of 1 mg/ml, 100 microg/ml and 30 microg/ml respectively, giving a potency order of formoterol > salmeterol > salbutamol. All displayed similar maximum effects in this system. A maximal concentration of salbutamol showed bronchoprotection at 1 h but not at 3 h post-dosing whereas maximal concentrations of formoterol and salmeterol showed protection up to 5 h post-aqueous-aerosol dosing, giving a duration order of salmeterol > formoterol > salbutamol. All three alpha(2)-adrenoceptor agonists showed dose-dependent bronchoprotection and duration of action following intravenous administration; salbutamol and salmeterol were equipotent and both were less potent than formoterol. Bronchoprotection obtained with sub-maximal concentrations of all three alpha(2)-adrenoceptor agonists faded within 30 min following iv administration, but this could be extended by increasing the doses. These results demonstrate that the route of administration is important in determining the duration of action of alpha(2)-adrenoceptor agonists in the lung. Furthermore, such findings lend support to the suggestion that the physico-chemical characteristics of salmeterol govern its duration of action rather than sustained binding of this agonist to a alpha(2)-adrenoceptor exo-site.

Administration, Inhalation↗
PubMed2000

A study of local electrostatic filtration and main pre-filtration on airborne and surface dust levels in air-conditioned office premises.

The impact of electrostatic precipitation as a useful form of particulate filtration in the breathing zone is investigated in an intervention study in an air-conditioned commercial office in central London. Surface dust deposition and airborne dust levels are measured in the open plan zones of two floors--a control floor and a floor where the intervention is effected. The intervention consists of a sequence of weekly scenarios where the main pre-filters of the air-handling unit are switched between new and old filters, and where the electrostatic filters, located as uniformly as practicable on the open plan areas, are switched on or off. This 2 x 2 set of interventions is repeated over 4 cycles. It was found that the breathing zone filtration (BZF) by electrostatic precipitators reduces airborne dust significantly and appears to be more efficient in reducing smaller sized particles. No significant effect of BZF filters in reducing surface dust deposition was detected.

Air Conditioning↗
PubMed2000

The diagnosis and management of acute childhood illness: is there a role for health visitors?

Much of the published literature on nurse practitioners relates to nurses with backgrounds, training and nursing experience other than health visiting. Health visitors however may be ideally placed to develop their role in the identification and management of acute childhood illness, and such a development may benefit patients, the health service and health visitors themselves. This study examines the current practice and attitudes of heath visitors in identifying and managing acute childhood illness using a postal questionnaire survey in one community National Health Service (NHS) Trust. The majority of responding health visitors reported that they were already identifying and advising on a range of acute childhood illnesses. Their confidence in undertaking these activities varied by condition. They were less confident in identifying and advising on conditions requiring the use of diagnostic equipment, viral illnesses which are becoming increasingly rare, and those with potentially serious outcomes. More knowledge and more training were seen as methods for increasing confidence. Most health visitors could see advantages in taking on this role; almost two thirds felt it would become part of the role of the health visitor in the future and a high level of interest was expressed in developing such a role.

Acute Disease↗