Biomedical subjects

J Agnew

Publications and source records attributed to J Agnew.

At least 19 recordsLinked to original sources

PubMed2006

The effects of vitamin C supplementation on symptoms of delayed onset muscle soreness.

AIM: The aim of this study was to compare the effects of 8 days of vitamin C (VC) supplementation on elbow flexor delayed onset muscle soreness (DOMS) to 8 days of placebo ingestion. METHODS: For 3 days prior to an exercise bout (2 x 20 eccentric elbow extensions), and for 5 days after, a treatment group ingested 3 x 1000 mg/day of VC versus 3 x 50 mg/day of glucose ingestion for the placebo group over the same time period. All subjects were prescreened via dietary recall to exclude any subjects with habitual VC consumption greater than 400 mg/day. Subject comprised 24 subjects (male and female) randomly divided into 2 groups of 12 subjects. Treatment group comprised 5 females and placebo group comprised 8 females. RESULTS: Data from a repeated measures ANOVA indicate that DOMS was successfully induced in both groups via significant time effects for strength loss (P = 0.0001), point tenderness (P = 0.0001), elbow flexor decreased range of motion (P = 0.013), and subjective pain (P = 0.0001). However, there were no significant between group differences in response to any of the aforementioned variables: strength loss (P = 0.202), point tenderness (P = 0.824), elbow flexor range of motion (P = 0.208), subjective pain (P = 0.342). CONCLUSIONS: The results of this study suggest that a VC supplementation protocol of 3 x 1000 mg/day for 8 days is ineffective in protecting against selected markers of DOMS.

Adult↗

PubMed2000

Interventions for the primary prevention of work-related carpal tunnel syndrome.

OBJECTIVE: To evaluate interventions for the primary prevention of work-related carpal tunnel syndrome (CTS). SELECTION CRITERIA: Studies had to include an engineering, administrative, personal, or multiple component intervention applied to a working or working-age population. All study designs that included comparison data were considered. Outcome measures included the incidence, symptoms, or risk factors for CTS, or a work-related musculoskeletal disorder of the upper extremity that included CTS in the definition. RESULTS: Twenty-four studies met our inclusion criteria. Engineering interventions included alternative keyboards, computer mouse designs and wrist supports, keyboard support systems, and tool redesign. Personal interventions included ergonomics training, splint wearing, electromyographic biofeedback, and on-the-job exercise programs. Multiple component interventions (e.g., ergonomic programs) included workstation redesign, establishment of an ergonomics task force, job rotation, ergonomics training, and restricted duty provisions. Multiple component programs were associated with reduced incidence rates of CTS, but the results are inconclusive because they did not adequately control for potential confounders. Several engineering interventions positively influenced risk factors associated with CTS, but the evaluations did not measure disease incidence. None of the personal interventions alone was associated with significant changes in symptoms or risk factors. All of the studies had important methodologic limitations that may affect the validity of the results. CONCLUSIONS: While results from several studies suggest that multiple component ergonomics programs, alternative keyboard supports, and mouse and tool redesign may be beneficial, none of the studies conclusively demonstrates that the interventions would result in the primary prevention of carpal tunnel syndrome in a working population. Given the societal impact of CTS, the growing number of commercial remedies, and their lack of demonstrated effec- tiveness, the need for more rigorous and long-term evaluation of interventions is clear. Fund- ing for intervention research should prioritize randomized controlled trials that include: (1) adequate sample size, (2) adjustment for relevant confounding variables, (3) isolation of speci- fic program elements, and (4) measurement of long-term primary outcomes such as the inci- dence of CTS, and secondary outcomes such as employment status and cost.

Carpal Tunnel Syndrome↗

PubMed2000

Just noticeable and objectionable group delays in digital hearing aids.

Group delay in a digital signal processing (DSP) hearing aid may be perceived as an echo in the sound heard by a wearer listening to his or her own voice, due to a combination of unprocessed sound received at the ear through head and air pathways and delayed sound reaching the eardrum through the hearing aid. Depending on the amount, this delay may be audible or objectionable and can even result in auditory confusion. This study presents results from 18 subjects listening to their own voices through a DSP hearing aid with a variable group delay. The subjects varied the length of the delay and determined the amounts that were noticeable and objectionable as compared to the undelayed condition, while listening to their own amplified voices. Results indicated that a delay of 3 to 5 msec was noticeable to the listeners in 76 percent of the trials, and a delay of longer than 10 msec was objectionable 90 percent of the time.

Adult↗

PubMed2000

Anti-psychotic drug prescribing trends in primary care in Scotland 1994-97.

OBJECTIVE: To describe trends in the use of anti-psychotic drugs prescribed in Primary Care in Scotland. DESIGN: Information on prescription numbers and costs were obtained from the Pharmacy Prescribing Division. SETTING: Scotland 1994-1997. Results Prescriptions for anti-psychotic drugs in Primary Care in Scotland increased by 28% in the period April 1994-December 97. In the same period, quarterly costs increased from 523,971 Pounds to 1,339,215 Pounds, an increase of 155%. Ninety per cent of the increase is accounted for by use of the five drugs risperidone, sertindole, olanzapine, clozapine and quetiapine. Health Board areas vary markedly in their uptake of the new drugs. CONCLUSION: The use of new anti-psychotic drugs in Scotland represents a substantial additional investment in mental health care. This has happened with little discussion or debate. Scotland needs to make explicit decisions on the place of newer anti-psychotics in treatment, and on the balance between investing in these drugs and investing in other aspects of mental health services.

Antipsychotic Agents↗

PubMed2000

Occupational health nursing research priorities: a changing focus.

This article reports a study to reexamine and update the research priorities in occupational health nursing. In this investigation, a 15% geographically proportionate random sample of AAOHN members was surveyed using a two-stage Delphi technique to determine important occupational health related areas needing targeted research. Research participants evaluated 37 potential research priorities in relation to impact on worker health and value to the profession, and 12 priorities emerged.

Adult↗

PubMed1999

Pharmacokinetics and pharmacodynamics following intravenous doses of azimilide dihydrochloride.

Azimilide pharmacokinetics and pharmacodynamics were characterized in a safety and tolerance study of intravenously administered azimilide dihydrochloride. This was a parallel-group design (seven treatments), and 68 healthy volunteers received the drug. Single intravenous infusion doses (4.5 to 9 mg/kg) were administered over 60 minutes, and single 4.5 mg/kg intravenous infusion doses were also given over 15 or 30 minutes. Blood and urine specimens were collected and analyzed for azimilide and metabolites. QTc was measured as a marker of class III antiarrhythmic activity. Azimilide pharmacokinetics were dose proportional and did not differ among infusion rates. Azimilide pharmacodynamics did not differ among treatments. Mean Emax ranged from 23 to 28% delta QTc, with mean EC50 of 509 to 566 ng/mL. Peak circadian variation in QTc was equivalent to 14% of Emax. Rapid equilibration occurred between blood and the biophase. Unconfounded pharmacodynamic estimates required inclusion of circadian QTc variation in the pharmacodynamic model.

Adolescent↗

PubMed1998

Depolarized resonance light scattering by porphyrin and chlorophyll a aggregates.

A quantum mechanical model is developed for the observed resonance enhancement of light scattering by aggregates of electronically interacting chromophores. Aggregate size, monomer oscillator strength, extent of electronic coupling, and aggregate geometry are all important determinants of intensity in resonance light scattering (RLS) spectra. The theory also predicts the value of the depolarization ratio (rho(v)(90)) of RLS for a given aggregate geometry. These results are used to interpret the RLS depolarization ratios of four aggregates: tetrakis(4-sulfonatophenyl)porphine aggregated at low pH (rho(v)(90) = 0.17 at 488 nm), trans-bis(N-methylpyridinium-4-yl)-diphenylporphinato copper(II) aggregated in 0.2 M NaCl solution (rho(v)(90) = 0.13 at 450 nm) and on calf thymus DNA (rho(v)(90) = 0.20 at 454 nm), and chlorophyll a aggregates in formamide/water (rho(v)(90) = 0.23 and 0.32 at 469 and 699 nm, respectively). The analysis is consistent with a J-aggregate geometry for all four systems. Furthermore, the specific values of rho(v)(90) allow us to estimate the orientation of the monomer transition dipoles with respect to the long axis of the aggregate. We conclude that depolarized resonance light scattering spectroscopy is a powerful probe of the geometric and electronic structures of extended aggregates of strong chromophores.

Animals↗

PubMed1997

Effect of age and gender on azimilide pharmacokinetics after a single oral dose of azimilide dihydrochloride.

Azimilide is a new class III antiarrhythmic drug that blocks K+ channels. To determine the effects of age and gender on azimilide pharmacokinetics, a single 150-mg oral dose was administered to 66 healthy volunteers in a 3 x 2 factorial design (age groups of 18-40, 41-64, and > or = 65 years). Blood and urine were analyzed for azimilide and metabolites. The single dose was well-tolerated. Azimilide was 94% plasma protein-bound, and binding was not affected by age or gender. Age does not affect azimilide pharmacokinetics. The renal clearance of azimilide was significantly higher in women than in men (19%), but oral clearance did not differ between genders. Although the maximum azimilide concentration (Cmax) was 27% higher in women, time to maximum concentration or area under the azimilide concentration-time curve were not different from those for men. Body weight-adjusted Cmax did not differ between genders. Dosing adjustments based on either age or gender are not required.

Administration, Oral↗

PubMed1997

Modulation of lipoxygenase activity by bacterial hopanoids.

Tetrahydroxybacteriohopane (1), a bacterial hopanoid, inhibited soybean 15-lipoxygenase with an IC50 of about 10 microM. After per-O-acetylation of 1 no inhibition of the 15-lipoxygenase was observed. Two other bacterial hopanoids, tetrahydroxybacteriohopane glucosamine (2) and tetrahydroxybacteriohopane ether (3), stimulated the activity of soybean 15-lipoxygenase. The activities of two other arachidonic acid-metabolizing enzymes, human 5-lipoxygenase and prostaglandin H synthase, were unaffected by 1.

Arachidonate 5-Lipoxygenase↗

PubMed1997

The perception of internal circuit noise in hearing aids by listeners with normal hearing.

Internal circuit noise in hearing aids is distracting to a listener and, if loud enough, may interfere with intelligibility, either by direct masking of weak components of speech or through the generation of undesired intermodulation products, which can also act as a source of masking. The objective characteristics of noise may be measured; however, wearers of hearing aids often differ in their subjective reporting of the perceived characteristics of the internal noise. This study reports on the results for four listeners with normal hearing of matching pitch and amplitude to the internal noise generated within a series of hearing aids. Results of these experiments showed that the listeners (a) primarily matched the perceived pitch of the noise to the frequency of their most sensitive hearing, and (b) matched the perceived level of the noise approximately to the total SPL noise level.

Adult↗

PubMed1997

Audible circuit noise in hearing aid amplifiers.

Audible electronic circuit noise generated within a hearing aid is distracting to a listener in quiet situations and, if the noise level is high enough, may cause listener irritation and rejection of the hearing aid. Thus for hearing aid specification and fitting purposes, it is useful to know the acoustic levels at which this internal noise may become audible and also at which it may become objectionable. For hearing aid amplifier circuit specification and design purposes, it is useful to know the same levels in electrical terms. This paper reports on a study that used an amplifier with no acoustic input and a hearing aid receiver output to simulate internally generated hearing aid circuit noise. Results are reported for testing eight subjects with high-frequency hearing loss for the perceived acoustic and electrical levels at which internal circuit noise became both audible and objectionable.

Amplifiers, Electronic↗

PubMed1997

Sound quality evaluation of anti-saturation circuitry in a hearing aid.

Loud sounds amplified by conventional hearing aids produce saturation distortion. This paper presents a comparison between a Class D hearing aid that was allowed to amplify into saturation and a Class D hearing aid that contained circuitry to prevent saturation distortion. The study was performed to determine whether users judged the conventional hearing aid or the anti-saturation hearing aid to have better sound quality. Seventeen subjects with hearing losses performed sound quality judgments at two sites. At low input levels, where the measured distortion was low, the subjects rated both hearing aids equal in sound quality. At high input levels, the subjects preferred the anti-saturation hearing aid, which had significantly lower distortion than the standard hearing aid. Though these data do not correlate the measured distortion to the subjective sound quality, the relationship revealed between the two in this testing warrants further investigation.

Correction of Hearing Impairment↗

PubMed1996

The centre for the vulnerable child: a new model for the therapeutic provision for abused children and their families.

In the last decade in Scotland there has been a rise in the number of known cases of children and adolescents who have experienced sexual abuse and a rise in the number of cases entering treatment after detection. This is putting a considerable strain on existing child and adult mental health services. As part of the response to this problem a new service was set up in Fife, the Centre for the Vulnerable Child, to provide an integrated focus for therapy, in-service training, consultancy and research into the area of sexual abuse. The Centre has strong links with the local joint police and social work Child Protection Unit with which it shares premises. Early indications are that the service is dealing primarily with more severely abused children. An evaluation is underway to assess both user satisfaction and the impact of this new service on measurable health and social outcomes among sexually abused children and their families. Professionals who have referred patients and clients to the Centre are largely satisfied with its work and an instrument for seeking the views of referred children is under development.

Adolescent↗

PubMed1996

Perception of internally generated noise in hearing amplification.

Noise generated within hearing aid amplifiers is distracting and, if the level is high enough, may interfere with speech communication. For hearing aid specification and fitting, it is useful to know the acoustic levels at which internal amplifier noise becomes audible and at which it becomes objectionable. This paper reports, for eight subjects with moderate hearing losses, the perceived levels at which internal noise became both audible and objectionable, using a test amplifier with no acoustic input. For comparison purposes, five normal-hearing subjects were also tested. Two noise sources were tested. The first was a broadband noise that was shaped only by the receiver, used to simulate output stage noise. The second was a broadband noise shaped by the target National Acoustics Laboratory-Revised (NAL-R) frequency response for each subject's hearing loss, used to simulate input stage noise. For both types of noise, the overall levels and spectra of the noise are reported for each subject. The relationship between 1/3-octave measurements of the noise and the audiometric configuration of the subjects is explored. The internal level at which the noise was perceived to be audible could be related to 1/3-octave measurements of the noise through the audiometric configuration of each subject's hearing loss. The results for the frequency-shaped input-generated noise and for the output-generated noise were similar.

Aged↗

PubMed1996

Detection of early asymptomatic esophageal dysfunction in systemic sclerosis using a new scintigraphic grading method.

OBJECTIVE: To screen patients with systemic sclerosis (SSc) for esophageal disease and to demonstrate a new system of grading dysmotility; to determine the relationship between the symptom of dysphagia and the degree of hypomotility shown by scintigraphy. METHODS: 301 patients with SSc were studied by esophageal scintigraphy using a semisolid orally ingested bolus to detect esophageal dysfunction and gastroesophageal reflux. A new system of grading was used to quantitate the degree of dysfunction, ranging from grade 0 (normal) to grade 4 (severe abnormality). RESULTS: 246 (82%) patients in the study population had evidence of esophageal hypomotility. Gastroesophageal reflux was noted in 83 (28%) patient. The largest number of patients (33%) were found to have grade 2 abnormalities. The number of patients with reflux decreased with increasing severity of grade, from grade 2 to grade 4 (35 to 13%). A retrospective study of the symptoms of 50 of the total study population showed that increasing severity of grade correlated with increasing mean duration of SSc. There was no significant relationship between disease subset and the presence or severity of esophageal hypomotility. 60% of patients in grades 1 and 2 (i.e. with observed dysmotility shown on scintigraphy) had no symptoms of dysphagia. In the more severe grades (scan grades 3 and 4), symptoms of dysphagia correlated with increase in grade. CONCLUSION: Symptoms may be unreliable in judging the presence of extent of esophageal disease in SSc. Esophageal scintigraphy is a useful noninvasive screening test for the detection of asymptomatic disease. The new grading system provides information that rapidly identifies the stage of esophageal disease and gives comparative data for followup and interventional studies.

Adolescent↗

PubMed1995

Comparison of neurobehavioral function in workers exposed to a mixture of organic and inorganic lead and in workers exposed to solvents.

The neurobehavioral effects of lead (organic and inorganic) and organic solvents were compared in 386 U.S. workers (52 reference, 190 lead, and 144 solvent workers). The association between neurobehavioral test performance and duration of exposure to lead or solvents was also examined and compared. The neurobehavioral test battery consisted of examiner and computer-administered neurobehavioral tests, a test of olfactory function, and questionnaires that assessed neuropsychiatric symptoms. Adjusted mean differences on the neurobehavioral test scores were estimated by comparing the exposed group to the referent group using linear regression and adjusting for premorbid intellectual ability, age, and race. Both lead and solvents were associated with diminished neurobehavioral performance in all neurobehavioral areas tested. Specifically, while lead and solvent exposure had the same magnitude of adverse effects on tests of manual dexterity, lead exposure was associated with greater adverse effects on memory and learning tests but with less adverse effects on executive/motor tests and on a test of olfaction than solvent exposure. An elevated number of neuropsychiatric symptoms was reported by 7% of the referent group, 43% of the lead group, and 15% of the solvent group. For exposure duration of < or = 10 years, more neurobehavioral decrements were found in the solvent group relative to the lead group. However, for exposure duration of > or = 18 years, the lead group showed more decrements than the solvent group. Overall, these data suggest differences in neurobehavioral functioning between the lead (organic and inorganic) and solvent exposed workers examined in this study.

Adult↗

PubMed1995

Perceptuomotor function of homeless males in alcohol rehabilitation.

In a sample of 76 alcohol rehabilitation program (ARP) residents, homeless men demonstrated significantly poorer perceptuomotor function than nonhomeless men. This difference persisted despite similarities in several factors associated with neurobehavioral test scores including demographic characteristics; frequency, quantity, and duration of alcohol and other substance use; psychosocial factors, including motivation and social support; health, including history of head trauma; and neurotoxic occupational exposure.

Adult↗

PubMed1993

Decrements in neurobehavioral performance associated with mixed exposure to organic and inorganic lead.

In 1990, 222 current employees of a chemical facility in the eastern United States that manufactured tetraethyl lead were administered a neurobehavioral test battery, tests of olfactory function and peripheral vibration threshold, and questionnaires that assessed neuropsychiatric symptoms. A cumulative variable of exposure to inorganic and organic lead was derived from 12 years of personal industrial hygiene sampling data and an occupational history interview that assessed work in each of 29 exposure zones in the lead area. The range of assigned exposure intensities in these 29 zones was 4-119 micrograms/m3 for organic lead and 1-56 micrograms/m3 for inorganic lead. Cumulative lead exposure and exposure duration were defined as categorical variables (four groups) in multiple linear regression models. The adjusted mean differences in neurobehavioral test scores were estimated by comparing the average scores of the moderate, high, and highest exposure groups with the low exposure (reference) group. After adjustment for premorbid intellectual ability, age, race, and alcohol consumption, neurobehavioral test scores were poorer as measures of both cumulative lead exposure and exposure duration increased; many of the associations evidenced dose-response relations. Associations were observed in most cognitive and functional domains tested, but were most common in two domains: manual dexterity and verbal memory/learning. On the affected neuropsychologic measures, the groups with the highest exposure averaged scores 5-22% lower than those of the reference groups. Overall, the data revealed generally consistent and coherent associations between two measures of lead exposure and poorer neurobehavioral test performance.

Adult↗