Biomedical subjects

J B Williams

Publications and source records attributed to J B Williams.

At least 19 recordsLinked to original sources

PubMed2006

Downhill treadmill running trains the rat spinotrapezius muscle.

There are currently no models of exercise that recruit and train muscles, such as the rat spinotrapezius, that are suitable for transmission intravital microscopic investigation of the microcirculation. Recent experimental evidence supports the concept that running downhill on a motorized treadmill recruits the spinotrapezius muscle of the rat. Based on these results, we tested the hypothesis that 6 wk of downhill running (-14 degrees grade) for 1 h/day, 5 days/wk, at a speed of up to 35 m/min, would 1) increase whole body peak oxygen uptake (Vo(2 peak)), 2) increase spinotrapezius citrate synthase activity, and 3) reduce the fatigability of the spinotrapezius during electrically induced 1-Hz submaximal tetanic contractions. Trained rats (n = 6) elicited a 24% higher Vo(2 peak) (in ml.min(-1).kg(-1): sedentary 58.5 +/- 2.0, trained 72.7 +/- 2.0; P < 0.001) and a 41% greater spinotrapezius citrate synthase activity (in mumol.min(-1).g(-1): sedentary 14.1 +/- 0.7, trained 19.9 +/- 0.9; P < 0.001) compared with sedentary controls (n = 6). In addition, at the end of 15 min of electrical stimulation, trained rats sustained a greater percentage of the initial tension than their sedentary counterparts (control 34.3 +/- 3.1%, trained 59.0 +/- 7.2%; P < 0.05). These results demonstrate that downhill running is successful in promoting training adaptations in the spinotrapezius muscle, including increased oxidative capacity and resistance to fatigue. Since the spinotrapezius muscle is commonly used in studies using intravital microscopy to examine microcirculatory function at rest and during contractions, our results suggest that downhill running is an effective training paradigm that can be used to investigate the mechanisms for improved microcirculatory function following exercise training in health and disease.

Animals↗

PubMed2006

Biodegradation of [(14)C] ring-labeled nonylphenol ethoxylate.

Nonylphenol (NP) and the 9-mole ethoxylate of nonylphenol (NPE9) were synthesized with a uniform radioactive (14)C label in the aromatic ring. The [(14)C]NP isomer distribution and [(14)C]NPE9 oligomer distribution closely matched that of commercial NPE9. Biodegradation of [(14)C]NPE9 was examined under conditions simulating a river water environment, and changes in the oligomer distribution and mineralization to (14)CO(2) were monitored for 128 days. Over 40% of the [(14)C]NPE aromatic ring carbon was converted to (14)CO(2) and another 21% was incorporated into the biomass. Primary degradation of NPE (conversion to metabolites other than NP, NPE ethoxylates, and NPE carboxylates) was estimated to be 87-97%. NP was a minor metabolite, accounting for less than 0.4% of the initial NPE. These studies demonstrate that the phenolic ring of NPE is opened, metabolized, and mineralized in the aquatic environment.

Bacteria, Aerobic↗

PubMed2006

Effects of immunisation against leptin on feed intake, weight gain, fat deposition and laying performance in chickens.

1. Three experiments were conducted to study the effects of leptin on weight gain and body composition in laying hens. 2. The effects of immunisation against chicken leptin on feed intake (FI), fat deposition and laying rate were observed in laying Guangdong yellow-feathered hens. Ten hens were inoculated with leptin immunogen on d 3, 31, 63 and 84, together with 10 control hens immunised with bovine serum albumin (BSA). In the 100-d experiment, immunisation against leptin increased blood anti-leptin antibody titres, slightly reduced plasma T3 concentrations, slightly decreased FI and increased live weight; however, laying rate was significantly depressed and abdominal fat mass was increased by the end of the 100-d experiment. 3. Passive immunisation of 50-d-old pullets with yolk extract containing anti-leptin antibody IgY significantly increased FI within 6 h of treatment compared with physiological saline treated controls. 4. In growing 70-d-old pullets, inoculation with 0.5 (group 1) or 1 (group 2) ml leptin immunogen on d 1 and 28 of the experiment slightly increased FI and significantly increased daily gain compared with BSA-immunised control pullets. Abdominal fat mass on d 49 increased from 48+/-4.5 g in controls to 66+/-3.5 and 80+/-3.1 g in groups 1 and 2, respectively. 5. It was suggested that immunisation against leptin mimicked loss of leptin bioactivity and might become a novel technique to stimulate fat growth in certain types of animal production.

Adipose Tissue↗

PubMed2004

Progressive changes in water and sediment quality in a wetland system for control of highway runoff.

Innovative wetland based systems were designed and installed on the Newbury Bypass, Berkshire, England to provide flow balancing and pollution control for road runoff. The systems were monitored over 18 months to evaluate performance, pollutant removal processes and offer improved design and operation codes for this new application of wetlands. Water quality, sediment accumulation rates, and metal concentrations in size-fractionated, settling solids and deposited sediments were determined in parts of the system to provide information on spatial and temporal variability. The results presented here show that over the long term, there were progressive changes in parts of the system for BOD and COD and for metal concentrations in the sediment fractions, which occurred with linear (or semi log-linear) rates, despite variability in flow rates, retention times and in pollutant loading to the system. Future work will continue monitoring to increase the data set, examine possible processes contributing to the regression constants, and test the potential use of the regressions in system modelling. Attempts at modelling road runoff treatment using wetlands must allow for progressions, since the systems can only be effective if they retain removed metals in the sediment sink.

England↗

PubMed2003

A phylogenetic analysis of basal metabolism, total evaporative water loss, and life-history among foxes from desert and mesic regions.

We measured basal metabolic rate (BMR) and total evaporative water loss (TEWL) of species of foxes that exist on the Arabian Peninsula, Blanford's fox (Vulpes cana) and two subspecies of Red fox (Vulpes vulpes). Combining these data with that on other canids from the literature, we searched for specialization of physiological traits among desert foxes using both conventional least squares regression and regressions based on phylogenetic independent contrasts. Further, we explored the consequences of reduced body size of foxes on life history parameters such as litter size and neonate mass. For Blanford's foxes, Red foxes from the central desert of Arabia, and Red foxes from the more mesic Asir mountains, body mass averaged 1,285 +/- 52 g, 1,967 +/- 289 g, and 3,060 +/- 482 g, respectively, whereas mean BMR, during summer, was 304.5 +/- 32.3 kJ/day, 418.0 +/- 32.4 kJ/day, and 724.1 +/- 120.2 kJ/day (+/- SD). An analysis of covariance with body mass as a covariate showed no statistical differences in BMR among foxes. Analysis of covariance indicated that Red fox from the Asir mountains had a higher TEWL than Red foxes from central Arabia or than Blanford's foxes also from the mountains. Comparisons of all species of desert and mesic foxes showed no significant differences in BMR, nor did desert foxes have a significantly lower BMR than other carnivores. TEWL of desert foxes was lower than other more mesic carnivores; deviations in TEWL ranged from -17.7% for the Fennec fox (Fennecus zerda) to -57.4% for the Kit fox (Vulpes velox). Although desert foxes have a BMR comparable to other more mesic species, it appears that desert foxes do have a smaller body mass, lowering overall energy requirements. We attribute this reduction in body size to the "resource limitation hypothesis" whereby natural selection favors smaller individuals in a resource-limited environment, especially during periods of severe food shortage. However, until common garden experiments are performed, developmental plasticity and acclimation cannot be ruled out as contributors to this pattern.

Adaptation, Physiological↗

PubMed2003

Behaviour of metals associated with sediments in a wetland based system for road runoff control.

Innovative road runoff control systems, which combined flow-balancing basins with constructed wetlands, on the recently constructed Newbury Bypass were monitored over 18 months. The results have shown that despite variability in the pollutant loadings, the system generally promoted removal and accumulation of sediments and associated metals. The correlation structure of the data set indicated possible removal processes, and enabled interpretation of the behaviour of these pollutants. Correlation of metal content in settling solids between successive upstream and downstream parts of the wetland gave indications of potential regression models for metal behaviour, despite variability in flows, pollutant loadings, and other conditions. Other findings suggested that the combined flow balancing and pollutant removal functions could be improved by avoiding transport of sediments, fluctuations in conditions and by the promotion of processes favouring metal retention by bed deposits.

Biodegradation, Environmental↗

PubMed2001

Dissipation of intersubband plasmons in wide quantum wells.

This Letter reports detailed measurements of the dissipation times tau(d) of approximately 10 meV intersubband (ISB) plasmons, and of the (single-particle) transport lifetimes tau(mu), in a remotely doped 40 nm GaAs quantum well. Introduced here as the time for ISB plasmons to dissipate into other modes of the electron gas, tau(d) is deduced from the homogeneous ISB absorption linewidth, measured as a function of sheet concentration and perpendicular dc electric field. Modeling in this and the next Letter [C. A. Ullrich and G. Vignale, Phys. Rev. Lett. 87, 037402 (2001)] indicates that scattering from rough interfaces dominates tau(d), while scattering from ionized impurities dominates tau(mu).

Journal Article↗

PubMed2001

Coherent manipulation of semiconductor quantum bits with terahertz radiation.

Quantum bits (qubits) are the fundamental building blocks of quantum information processors, such as quantum computers. A qubit comprises a pair of well characterized quantum states that can in principle be manipulated quickly compared to the time it takes them to decohere by coupling to their environment. Much remains to be understood about the manipulation and decoherence of semiconductor qubits. Here we show that hydrogen-atom-like motional states of electrons bound to donor impurities in currently available semiconductors can serve as model qubits. We use intense pulses of terahertz radiation to induce coherent, damped Rabi oscillations in the population of two low-lying states of donor impurities in GaAs. Our observations demonstrate that a quantum-confined extrinsic electron in a semiconductor can be coherently manipulated like an atomic electron, even while sharing space with approximately 10(5) atoms in its semiconductor host. We anticipate that this model system will be useful for measuring intrinsic decoherence processes, and for testing both simple and complex manipulations of semiconductor qubits.

Journal Article↗

PubMed2001

Standardizing the Hamilton Depression Rating Scale: past, present, and future.

The Hamilton Depression Rating Scale (HAM-D) has become the most widely used depression severity rating scale in the world. It was originally published by Max Hamilton in 1960 to measure severity of depression in previously diagnosed depressed inpatients. Since that time, multiple versions of the scale have been created, although authors are rarely clear about which version they used. In addition, structured interview guides, self-report forms, and computerized versions have been developed in an effort to standardize administration of the scale and improve the psychometric characteristics of the individual items. The history of the development of these features is discussed, and the various versions of the scale are summarized in tables. This article is a fitting tribute to Per Bech, who has contributed so much to the assessment of depression severity.

Depressive Disorder↗

PubMed2001

Fate, effects and potential environmental risks of ethylene glycol: a review.

The fate, effects, and potential environmental risks of ethylene glycol (EG) in the environment were examined. EG undergoes rapid biodegradation in aerobic and anaerobic environments (approximately 100% removal of EG within 24 h to 28 days). In air, EG reacts with photo-chemically produced hydroxyl radicals with a resulting atmospheric half-life of 2 days. Acute toxicity values (LC(50)s and EC(50)s) were generally >10,000 mg/l for fish and aquatic invertebrates. The data collectively show that EG is not persistent in air, surface water, soil, or groundwater, is practically non-toxic to aquatic organisms, and does not bioaccumulate in aquatic organisms. Potential long-term, quasi-steady state regional concentrations of EG estimated with a multi-media model for air, water, soil, and sediment were all less than predicted no effect concentrations (PNECs).

Amphibians↗

PubMed2001

Health problems, impairment and illnesses associated with bulimia nervosa and binge eating disorder among primary care and obstetric gynaecology patients.

BACKGROUND: Although psychiatric patients with eating disorders are known to be at risk for a variety of health problems, relatively little is known about eating disorders and associated health problems in other populations. An epidemiological study was conducted to investigate health problems and impairment associated with bulimia nervosa (BN) and binge eating disorder (BED) among female primary care and obstetric gynaecology patients. METHODS: Psychiatric disorders, physical illnesses, disabilities, functional status and stress were assessed among 4651 female patients (age range:18 to 99 years) at 8 primary care and 7 obstetric gynaecology clinics throughout the United States. RESULTS: Two hundred eighty-nine women (62%) were diagnosed with BN or BED. The prevalence of BN was approximately 1% among young and middle-aged women. The prevalence of BED increased steadily from early (3.3%) through middle (8.5%) adulthood. Anxiety disorders, mood disorders and diabetes were much more common among women with BN or BED than among women without these eating disorders. Women with BN or BED reported markedly poorer functioning and much higher levels of disability, health problems, insomnia, psychosocial stress and suicidal thoughts than did women without BN or BED, after co-occurring psychiatric disorders were controlled statistically. Yet, fewer than one of ten cases of BN or BED was recognized by the patients' physicians. CONCLUSIONS: Patients with BN or BED often experience considerable disability, impairment, distress and co-occurring illnesses. Increased recognition of eating disorders may be a crucial step towards encouraging more patients to seek treatment for these disabling conditions.

Adolescent↗

PubMed2001

Hopelessness as a mediator of the association between social support and depressive symptoms: findings of a study of men with HIV.

Data from a prospective longitudinal study were used to investigate whether hopelessness mediates the association between social support and depression, as hypothesized by L. Y. Abramson, G. I. Metalsky, and L. B. Alloy (1989). Measures of hopelessness, social support, and depression were administered to 103 HIV-infected men and readministered 6 months later. Findings indicated that low baseline social support predicted increases in hopelessness and depression. Increases in hopelessness predicted increases in depression after controlling for baseline social support. Low baseline social support did not predict increased depression when hopelessness was controlled statistically.

Adult↗

PubMed2001

The PHQ-9: validity of a brief depression severity measure.

OBJECTIVE: While considerable attention has focused on improving the detection of depression, assessment of severity is also important in guiding treatment decisions. Therefore, we examined the validity of a brief, new measure of depression severity. MEASUREMENTS: The Patient Health Questionnaire (PHQ) is a self-administered version of the PRIME-MD diagnostic instrument for common mental disorders. The PHQ-9 is the depression module, which scores each of the 9 DSM-IV criteria as "0" (not at all) to "3" (nearly every day). The PHQ-9 was completed by 6,000 patients in 8 primary care clinics and 7 obstetrics-gynecology clinics. Construct validity was assessed using the 20-item Short-Form General Health Survey, self-reported sick days and clinic visits, and symptom-related difficulty. Criterion validity was assessed against an independent structured mental health professional (MHP) interview in a sample of 580 patients. RESULTS: As PHQ-9 depression severity increased, there was a substantial decrease in functional status on all 6 SF-20 subscales. Also, symptom-related difficulty, sick days, and health care utilization increased. Using the MHP reinterview as the criterion standard, a PHQ-9 score > or =10 had a sensitivity of 88% and a specificity of 88% for major depression. PHQ-9 scores of 5, 10, 15, and 20 represented mild, moderate, moderately severe, and severe depression, respectively. Results were similar in the primary care and obstetrics-gynecology samples. CONCLUSION: In addition to making criteria-based diagnoses of depressive disorders, the PHQ-9 is also a reliable and valid measure of depression severity. These characteristics plus its brevity make the PHQ-9 a useful clinical and research tool.

Adult↗

PubMed2001

Seasonal variation in energy expenditure, water flux and food consumption of Arabian oryx Oryx leucoryx.

We report on the energy expenditure and water flux, measured in the laboratory and in the field, of the Arabian oryx Oryx leucoryx, the largest desert ruminant for which measurements of the field metabolic rate of free-living individuals have been made using doubly labeled water. Prior to extirpation of this species in the wild in 1972, conservationists sequestered a number of individuals for captive breeding; in 1989, oryx were reintroduced in Saudi Arabia into Mahazat as-Sayd (2244 km(2)). Apart from small pools of water available after rains, oryx do not have free-standing water available for drinking and therefore rely on grasses that they eat for preformed water intake as well as their energy needs. We tested whether oryx have a reduced fasting metabolic rate and total evaporative water loss (TEWL) in the laboratory, as do some other arid-adapted mammals, and whether oryx have high field metabolic rates (FMRs) and water influx rates (WIRs), as predicted by allometric equations for large arid-zone mammals. We measured FMR and WIR during the hot summer, when plant moisture content was low and ambient temperatures were high, and after winter rains, when the water content of grasses was high. For captive oryx that weighed 84.1 kg, fasting metabolic rate averaged 8980 kJ day(-1), 16.7% lower than predictions for Artiodactyla. Our own re-analysis of minimal metabolic rates among Artiodactyla yielded the equation: logV(O2)=-0.153+0.758logM, where V(O2) is the rate of oxygen uptake in lh(-1) and M is body mass in kg. Fasting metabolic rate of oryx was only 9.1% lower than predicted, suggesting that they do not have an unusually low metabolic rate. TEWL averaged 870.0 ml day(-1), 63.9% lower than predicted, a remarkably low value even compared with the camel, but the mechanisms that contribute to such low rates of water loss remain unresolved. For free-living oryx, FMR was 11076 kJ day(-1) for animals with a mean body mass of 81.5 kg during summer, whereas it was 22081 kJ day(-1) for oryx in spring with a mean body mass of 89.0 kg, values that were 48.6% and 90.4% of allometric predictions, respectively. During summer, WIR averaged 1310 ml H(2)O day(-1), whereas in spring it was 3438 ml H(2)O day(-1). Compared with allometric predictions, WIR was 76.9% lower than expected in summer and 43.6% lower in spring. We found no evidence to support the view that the WIR of large desert ungulates is higher than that of their mesic counterparts. On the basis of the WIR of the oryx averaged over the year and the water contents of plants in their diet, we estimated that an oryx consumes 858 kg of dry matter per year.

Animals↗

PubMed2001

Ultimate biodegradation of alkylphenol ethoxylate surfactants and their biodegradation intermediates.

The ultimate biodegradation of the commercial products nonylphenol ethoxylates (NPE9), octylphenol ethoxylates (OPE9), and their biodegradation intermediates, NPE1.5, OPE1.5, NP, and OP, was measured using conventional methods. The extent of biodegradation was also determined by gas chromatography/mass spectrometry (GC/MS) and high-performance liquid chromatography (HPLC) analysis of metabolites and measurement of dissolved organic carbon. Optimized pseudo-first order degradation rate constants and half-lives were calculated from these data and from previously published data, using Larson's equation for surfactant degradation kinetics. Ultimate aerobic biodegradation of alkylphenol ethoxylates and their biodegradation intermediates has now been examined using acclimated wastewater treatment plant sludge as the microbial seed, household wastewater treatment systems, and unacclimated fresh water, seawater, and soil. Ultimate biodegradation half-lives ranged from about one to four weeks and provide definitive evidence for the extensive biodegradability of alkyphenol ethoxylates (APE) surfactants and their metabolites and their lack of persistence in the environment.

Bacteria, Aerobic↗

PubMed2001

Metals in combined conventional and vegetated road runoff control systems.

Combined conventional and vegetated runoff treatment systems were installed on the rural Newbury Bypass in Southern England, which was estimated to carry an average daily traffic of 30,000 vehicles. The system components were arranged in series to give progressive pollutant removal, comprising an oil separator, sediment trap, grassy slope and constructed wetland. In the absence of specific design criteria for road runoff control, the system design was based on available guidance notes. Since the road opened, an 18-month monitoring programme has examined the performance of these systems. Early indications are that the systems, and especially the wetlands, promote removal of suspended solids (>1.2 microm) and effectively trap fine (<63 microm) sediments. The waters were generally oxidising with neutral to basic pH which may have favoured metal partitioning to the solid phase. The distribution pattern for Zn and Cu in fine sediments contrasted in two of the systems studied, indicating the complex behaviour of metals in wetlands. Further work will increase the data set and examine the adsorption behaviour of metals. These results will contribute to the development of future design criteria for the application of wetlands to road runoff treatment.

Adsorption↗

PubMed2000

Frequency and clinical determinants of dementia after ischemic stroke.

OBJECTIVE: To investigate the frequency and clinical determinants of dementia after ischemic stroke. METHODS: The authors administered neurologic, neuropsychological, and functional assessments to 453 patients (age 72.0 +/- 8.3 years) 3 months after ischemic stroke. They diagnosed dementia using modified Diagnostic and Statistical Manual of Mental Disorders, 3rd ed., revised criteria requiring deficits in memory and two or more additional cognitive domains as well as functional impairment. RESULTS: The authors diagnosed dementia in 119 of the 453 patients (26.3%). Regarding dementia subtypes, 68 of the 119 patients (57.1%) were diagnosed with vascular dementia, 46 patients (38.7%) were diagnosed with AD with concomitant stroke, and 5 patients (4.2%) had dementia for other reasons. Logistic regression suggested that dementia was associated with a major hemispheral stroke syndrome (OR 3.0), left hemisphere (OR 2.1) and right hemisphere (OR 1.8) infarct locations versus brainstem/cerebellar locations, infarcts in the pooled anterior and posterior cerebral artery territories versus infarcts in other vascular territories (OR 1.7), diabetes mellitus (OR 1.8), prior stroke (OR 1.7), age 80 years or older (OR 12.7) and 70 to 79 years (OR 3.9) versus 60 to 69 years, 8 or fewer years of education (OR 4.1) and 9 to 12 years of education (OR 3.0) versus 13 or more years of education, black race (OR 2.6) and Hispanic ethnicity (OR 3.1) versus white race, and northern Manhattan residence (OR 1.6). CONCLUSIONS: Dementia is frequent after ischemic stroke, occurring in one-fourth of the elderly patients in the authors' cohort. The clinical determinants of dementia include the location and severity of the presenting stroke, vascular risk factors such as diabetes mellitus and prior stroke, and host characteristics such as older age, fewer years of education, and nonwhite race/ethnicity. The results also suggest that concomitant AD plays an etiologic role in approximately one-third of cases of dementia after stroke.

Aged↗

PubMed2000

Effects of opioids on driving ability.

Driving has been regarded as an activity of daily living that is important in maintaining a person's independence in the community, access to employment, and social activities. Many patients, however, using opioid medications on a regular basis (Chronic Opioid Analgesic Therapy: COAT) to ameliorate their intractable pain have been restricted from driving out of concern that skills would be impaired and driving safety compromised by these medications. Yet there are no driving studies which have explored the effects of using opioid analgesics for an extended period of time. This pilot study was designed to determine the effects of medically prescribed, stable opioid use on the driving abilities of patients with persistent, nonmalignant pain. Sixteen patients with chronic nonmalignant pain on COAT, who met criteria for participation in the study, underwent a comprehensive off-road driving evaluation using measures which have been shown to be sensitive in predicting on-road driving performance. The evaluation consisted of a pre-driver evaluation (PDE), a simulator evaluation (SDE), and behavioral observation during simulator performance. Patients in the COAT group were compared to a historical control group of 327 cerebrally compromised patients (CComp) who had undergone the same evaluation and then passed an on-road, behind-the-wheel evaluation (BTW Pass; n = 162) or failed (BTW Fail; n = 165). Results revealed that COAT patients generally outperformed the CComp patients as a group by equaling or exceeding PDE and SDE scores of the BTW Fail patients as well as the BTW Pass patients on all measures that differentiated the groups. Notably, COAT patients had a relatively poorer performance than CComp patients on specific neuropsychometric tests in the PDE; however, the differences were not statistically significant and did not imply a systematic pattern of scores that reflected domain-specific deficits. Behaviorally, COAT patients were generally superior to CComp patients, also; however, COAT patients had greater difficulty in following instructions and as well as a tendency toward impulsivity, like the BTW fail group. While there was general support for the notion that COAT did not significantly impair the perception, cognition, coordination, and behavior measured in off-road tests that have been regarded as requisite for on-road driving, methodological problems may limit the generalizability of results and recommendations are made for research beyond a pilot study.

Analgesics, Opioid↗