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Biomedical subjects

J Richards

Publications and source records attributed to J Richards.

At least 37 records · Page 2Linked to original sources
PubMed2002

Treatment requirements of infants with rhesus isoimmunisation within a geographically defined area.

OBJECTIVE: To provide population based data on the treatment requirements of infants with rhesus isoimmunisation. SETTING: Twenty nine hospitals in South Thames in which 81 119 deliveries occurred between February 1999 and January 2000. DESIGN: Every month, a clinician identified in each of the hospitals sent back a postcard indicating whether or not an infant with RhD had required treatment in their institution. Antenatal and postnatal information was then requested from all those who gave positive responses. MAIN OUTCOME MEASURES: Requirement for postnatal treatment for rhesus isoimmunisation. RESULTS: During the one year study period, only 26 infants required treatment for rhesus isoimmunisation. The median duration of phototherapy of the 26 infants was five days (range 1-12). Seven infants required at least one exchange transfusion (two required two exchange transfusions), and seven infants received one "top up" transfusion. None received erythropoietin and no infant died. CONCLUSION: The results suggest that few infants require treatment for rhesus isoimmunisation.

Exchange Transfusion, Whole Blood↗
PubMed2002

Monitoring antibiotic resistance in urinary isolates from the community--a spotter practice model.

Awareness of the rise in antimicrobial resistance has led to recommendations for better prescribing guidelines, based on accurate laboratory sensitivity data. However, concerns have been raised of possible biases in sampling leading to skewed resistance rates results, and so a range of different enhanced surveillance models have been proposed. This study compared the differences between routine results from unselected primary care urine samples with results from samples from spotter practices. Five hundred and eighty-eight out of 2,288 urine samples received from three spotter practices were culture positive. Of the 510 isolates tested against a panel of commonly prescribed antibiotics, levels of resistance to ampicillin were 32.5%, and to trimethoprim 18.0% (p < 0.05). By comparison, of 40,026 urine specimens submitted by other practices, 9,382 were culture positive and the percentage antibiotic resistant was higher--36.3% to ampicillin and 22.6% to trimethoprim. Routinely submitted laboratory samples may overestimate the true levels of antibiotic resistance in the community. A spotter practice-model is an effective and viable way of collecting unbiased data.

Anti-Bacterial Agents↗
PubMed2001

Feline vaccination guidelines.

The 1998 Report of the American Association of Feline Practitioners and Academy of Feline Medicine Advisory Panel on Feline Vaccines was developed to help veterinary practitioners formulate vaccination protocols for cats. The current panel report updates information, addresses questions, and speaks to concerns raised by the 1998 report. In addition it reviews vaccine licensing, labeling, and liability issues and suggests ways to successfully incorporate vaccination protocol changes into a private practice setting.

Animals↗
PubMed2001

Deposition and pharmacokinetics of flunisolide delivered from pressurized inhalers containing non-CFC and CFC propellants.

Our objective was to assess the deposition and pharmacokinetics of a novel formulation of flunisolide (Aerobid, Forest Laboratories) in hydrofluoroalkane (HFA) 134a delivered by pressurized metered dose inhaler (pMDI). The design was a two-way crossover investigation in 12 healthy male subjects comparing HFA-134a flunisolide by pMDI versus pMDI plus 50 mL spacer device. Four of these subjects also took part in a two-way crossover investigation comparing chlorofluorocarbon (CFC) flunisolide pMDI versus pMDI plus Aerochamber holding chamber. The imaging technique of gamma scintigraphy was used to quantify total and regional lung deposition of flunisolide. Plasma levels of flunisolide and its major metabolite (6beta-OH flunisolide) were also determined. The spacer and Aerochamber reduced oropharyngeal deposition dramatically for both the HFA and CFC products (mean 59.8 to 14.9% (p < 0.01) of ex-valve (metered) dose for HFA product; 66.3 to 12.3% (p < 0.01) of ex-valve dose for CFC product) owing to deposition of part of the dose on the walls of the add-on devices themselves. Lung deposition averaged 22.6 and 40.4% (p < 0.01) of the ex-valve dose for the HFA formulation used with pMDI alone and with pMDI plus spacer. Mean lung deposition of the CFC formulation delivered via the Aerochamber (mean 23.4%) was higher than that for the CFC pMDI alone (mean 17.0%), but this difference was not statistically significant. Lung deposition expressed as percentage ex-device (delivered) dose averaged 68.3% for HFA pMDI plus spacer and 19.7% for CFC pMDI. Plasma levels of flunisolide were higher for the pMDI plus spacer than for pMDI alone, reflecting higher lung deposition via the spacer, but plasma levels of the 6beta-OH flunisolide metabolite were higher for the pMDI alone as a consequence of higher oropharyngeal deposition. When delivered via the spacer, pulmonary targeting of the flunisolide HFA formulation was improved compared with the CFC formulation, which should benefit patients by providing satisfactory asthma therapy from a much-reduced delivered dose of flunisolide.

Administration, Inhalation↗
PubMed2001

Frequent overcrowding in U.S. emergency departments.

OBJECTIVE: To describe the definition, extent, and factors associated with overcrowding in emergency departments (EDs) in the United States as perceived by ED directors. METHODS: Surveys were mailed to a random sample of EDs in all 50 states. Questions included ED census, frequency, impact, and determination of overcrowding. Respondents were asked to rank perceived causes using a five-point Likert scale. RESULTS: Of 836 directors surveyed, 575 (69%) responded, and 525 (91%) reported overcrowding as a problem. Common definitions of overcrowding (>70%) included: patients in hallways, all ED beds occupied, full waiting rooms >6 hours/day, and acutely ill patients who wait >60 minutes to see a physician. Overcrowding situations were similar in academic EDs (94%) and private hospital EDs (91%). Emergency departments serving populations < or =250,000 had less severe overcrowding (87%) than EDs serving larger areas (96%). Overcrowding occurred most often several times per week (53%), but 39% of EDs reported daily overcrowding. On a 1-5 scale (+/-SD), causes of overcrowding included high patient acuity (4.3 +/- 0.9), hospital bed shortage (4.2 +/- 1.1), high ED patient volume (3.8 +/- 1.2), radiology and lab delays (3.3 +/- 1.2), and insufficient ED space (3.3 +/- 1.3). Thirty-three percent reported that a few patients had actual poor outcomes as a result of overcrowding. CONCLUSIONS: Episodic, but frequent, overcrowding is a significant problem in academic, county, and private hospital EDs in urban and rural settings. Its causes are complex and multifactorial.

Crowding↗
PubMed2001

Oxidative interactions of synthetic lung epithelial lining fluid with metal-containing particulate matter.

Epidemiology studies show association of morbidity and mortality with exposure to ambient air particulate matter (PM). Metals present in PM may catalyze oxidation of important lipids and proteins present in the lining of the respiratory tract. The present study investigated the PM-induced oxidation of human bronchoalveolar lavage (BAL) fluid (BALF) and synthetic lung epithelial lining fluid (sELF) through the measurement of oxygen incorporation and antioxidant depletion assays. Residual oil fly ash (ROFA), an emission source PM that contains approximately 10% by weight of soluble transition metals, was added (0-200 microg/ml) to BALF or sELF and exposed to 20% (18)O(2) (24 degrees C, 4 h). Oxygen incorporation was quantified as excess (18)O in the dried samples after incubation. BALF and diluted sELF yielded similar results. Oxygen incorporation was increased by ROFA addition and was enhanced by ascorbic acid (AA) and mixtures of AA and glutathione (GSH). AA depletion, but not depletion of GSH or uric acid, occurred in parallel with oxygen incorporation. AA became inhibitory to oxygen incorporation when it was present in high enough concentrations that it was not depleted by ROFA. Physiological and higher concentrations of catalase, superoxide dismutase, and glutathione peroxidase had no effect on oxygen incorporation. Both protein and lipid were found to be targets for oxygen incorporation; however, lipid appeared to be necessary for protein oxygen incorporation to occur. Based on these findings, we predict that ROFA would initiate significant oxidation of lung lining fluids after in vivo exposure and that AA, GSH, and lipid concentrations of these fluids are important determinants of this oxidation.

Antioxidants↗
PubMed2001

Bladder function in Utricularia purpurea (Lentibulariaceae): is carnivory important?

Utricularia purpurea is a rootless, free-floating, aquatic, carnivorous plant. I quantified biomass investment in U. purpurea traps and determined when traps begin to function and what they trap in natural habitats. In the Everglades of south Florida, plants invest an average of 26% of their biomass in bladders, although bladder number varies among sites and over time. Leaves begin trapping as they mature, and on leaves one whorl older than the most recently matured leaves, almost 100% of bladders have allochthonous material. Despite the substantial investment in their biomass, bladders capture few aquatic microinvertebrates. Almost all mature bladders, however, have living communities of algae, zooplankton, and associated debris. These results support the hypotheses that the important association in U. purpurea bladders is a mutualism rather than a predator-prey interaction and that the major benefit to the plants from bladders is derived from this community.

Journal Article↗
PubMed2000

The feasibility of a kinematic measure of lip closure during meaningful speech.

PURPOSE: Assessment of dysarthria has traditionally been based on perceptual methods. The purpose of this study was to examine the feasibility of using 2D kinematic analysis to measure lip closure during normal speech. METHOD: Retroflective markers (4 mm diameter) were placed on the midline of each lip of three healthy male, caucasian volunteers aged 69 years who repeated the sentence 'My mother made me an apple and blackberry pie' six times. Videorecordings were analysed using the Ariel Performance Analysis System to calculate the distance between the lips before, during and after the sentence. RESULTS: The graphs produced from the data objectively measured the distance between the lips and identified the eight bilabial sounds. However, in spite of stringent study criteria to minimize differences linked to age, gender and race, differences were found between participants. CONCLUSION: Kinematic 2D analysis may have potential for the objective measurement of lip closure in dysarthria in the context of meaningful speech. These results justify further pilot work to explore: the possible variability within defined populations; and the usefulness of 2D kinematic analysis in the measurement of disordered lip closure in dysarthria.

Aged↗
PubMed2000

Disease and gill lesions in yellow perch (Perca flavescens) exposed to oil sands mining-associated waters.

Adult yellow perch were stocked into experimental ponds designed to test the biological effects of aquatic reclamation alternatives currently being pursued by the oil sands mining industry. Water-quality characteristics of oil sands-influenced water in the experimental ponds included increased salinity and elevated trace organics associated with raw oil sands (bitumen). After 3 and 10 months of exposure to affected waters, perch gross pathologies including severe fin erosion and virally induced tumors were observed in exposed individuals. Gill histopathology revealed large aneurysms accompanied by a proliferation of chloride and epithelial cells in the interlamellar spaces. Gill pathologies were not paralleled by a decrease in plasma sodium, calcium, or chloride. The frequencies of gross pathologies and gill changes were correlated to the concentrations of the oil sands-related compounds. As inorganic and organic compounds associated with oil sands activities are highly intercorrelated, and the observed lesions and changes are not diagnostic of particular toxicants, it was not possible to isolate the causative chemical factor(s) responsible. The incidence of observed lesions and gill pathologies could not be conclusively linked to increased mortality rates observed in the exposed populations. Evidence of recovery in the pathologies was observed between 3 and 10 months of exposure, coincident with a stabilization in population numbers.

Animals↗
PubMed2000

"Wet Voice" as a predictor of penetration and aspiration in oropharyngeal dysphagia.

This article describes the results of a study that investigated how well wet phonation can predict penetration and/or aspiration of ingested material in dysphagic patients. Voice samples of 23 subjects with neurologic oropharyngeal dysphagia were collected immediately after each subject had swallowed nine different boluses on videofluoroscopy. The boluses were graded according to three different consistencies and three different sizes. The presence of wetness in the voice was analyzed in relation to any ingested material that remained in the larynx or trachea after each bolus was swallowed. Results showed that there was no association between the presence of a wet voice and penetration or aspiration of prandial material after a swallow. The importance of detecting wet phonation by itself was therefore not considered diagnostic in detecting prandial penetration/aspiration by the bedside, but a wet voice may still be useful in identifying those with dysphagia who may have laryngeal dysfunction and therefore may be at risk of penetrating/aspirating any type of material, not just prandial material.

Adult↗
PubMed2000

Comparison of surface mounted markers and attachment methods in estimating tibial rotations during walking: an in vivo study.

The overall goal of this work was to determine an optimal surface-tracking marker set for tracking motion of the tibia during natural cadence walking. Eleven different marker sets were evaluated. The marker sets differed in the location they were attached to the shank, the method used to attach the marker sets to the segment and the physical characteristics of the marker sets. Angular position during stance for each marker set was expressed relative to the orientation of the tibia as measured using bone anchored markers. A marker set consisting of four markers attached to a rigid shell positioned over the distal lateral shank and attached to the leg using an underwrap attachment yielded the best estimate of tibial rotation. Rotational deviations of+/-2 degrees about the medio-lateral and antero-posterior axes, and+/-4 degrees about the longitudinal axis did occur even when using the optimal set of markers.

Gait↗
PubMed2000

Validity and reliability of a kinematic protocol for determining foot contact events.

Timing of foot contact events provides important information for gait studies. The aim of the study is to validate the use of kinematic data, collected at 50 Hz to define foot contact events during gait initiation. Simultaneous kinetic and kinematic data recordings of four discrete foot contact events were made for normal adults. Raters were asked to estimate the timing of the events from kinematic data curves and these timings were compared with those derived from the kinetic data. For the four events, between 88 and 98% of all ratings were accurate to within 0.03 s. Inter-rater reliability was extremely high, reflecting the precision of the definitions used.

Adult↗
PubMed2000

Prediction of bone strength of distal forearm using radius bone mineral density and phalangeal speed of sound.

This investigation compares quantitative ultrasound (QUS) measurement of the phalanges with peripheral quantitative computed tomography (pQCT) and dual X-ray absorptiometry (DXA) measurement of the forearm, to estimate the strength of the distal radius in 13 cadaveric forearms. The cadavers were scanned at the distal radius by pQCT and DXA for bone mineral density (BMD) and at the approximate phalanges by QUS for speed of sound (SOS). The distal radii were subjected to a simulated Colles fracture produced with a materials testing machine. The load at which the distal radius was fractured was considered as a representation of bone strength. The bone strength correlated significantly with SOS at different phalanges (r = 0.63-0.72), BMD at different regions of interest by DXA (r = 0.67-0.75), and cortical BMD at different sites by pQCT (r = 0.61-0.67). Standard stepwise regression analysis showed that adding phalangeal SOS into forearm densitometric variables significantly enhanced the statistical power for prediction of the strength of the distal radius. Our results suggest that, for assessment of site-specific distal forearm strength, QUS measurement of the phalanges is comparable to forearm densitometry. Phalangeal QUS may add clinical value if distal forearm strength has a high priority.

Aged↗
PubMed2000

Variable pulmonary responses from exposure to concentrated ambient air particles in a rat model of bronchitis.

Chronic bronchitis may be considered a risk factor in particulate matter (PM)-induced morbidity. We hypothesized that a rat model of human bronchitis would be more susceptible to the pulmonary effects of concentrated ambient particles (CAPs) from Research Triangle Park, NC. Bronchitis was induced in male Sprague-Dawley rats (90-100 days of age) by exposure to 200 ppm sulfur dioxide (SO2), 6 h/day x 5 days/week x 6 weeks. One day following the last SO2 exposure, both healthy (air-exposed) and bronchitic (SO2-exposed) rats were exposed to filtered air (three healthy; four bronchitic) or CAPs (five healthy; four bronchitic) by whole-body inhalation, 6 h/day x 2 or 3 days. Pulmonary injury was determined either immediately (0h) or 18 h following final CAPs exposure. The study protocol involving 0 h time point was repeated four times (study #A, November, 1997; #B, February, 1998; #C and #D, May, 1998), whereas the study protocol involving 18 h time point was done only once (#F). In an additional study (#E), rats were exposed to residual oil fly ash (ROFA), approximately 1 mg/ m(3)x6 h/day x 3 days to mimic the CAPs protocol (February, 1998). The rats allowed 18 h recovery following CAPs exposure (#F) did not depict any CAPs-related differences in bronchoalveolar lavage fluid (BALF) injury markers. Of the four CAPs studies conducted (0 h time point), the first (#A) study (approximately 650 microg/m3 CAPs) revealed significant changes in the lungs of CAPs-exposed bronchitic rats compared to the clean air controls. These rats had increased BALF protein, albumin, N-acetyl glutaminidase (NAG) activity and neutrophils. The second (#B) study (approximately 475 microg/m3 CAPs) did not reveal any significant effects of CAPs on BALF parameters. Study protocols #C (approximately 869 microg/m3 CAPs) and #D (approximately 907 microg/m3 CAPs) revealed only moderate increases in the above mentioned BALF parameters in bronchitic rats exposed to CAPs. Pulmonary histologic evaluation of studies #A, #C, #D, and #F revealed marginally higher congestion and perivascular cellularity in CAPs-exposed bronchitic rats. Healthy and bronchitic rats exposed to ROFA (approximately 1 mg/m3) did not show significant pulmonary injury (#E). Analysis of leachable elemental components of CAPs revealed the presence of sulfur, zinc, manganese, and iron. There was an apparent lack of association between pulmonary injury and CAPs concentration, or its leachable sulfate or elemental content. In summary, real-time atmospheric PM may result in pulmonary injury, particularly in susceptible models. However, the variability observed in pulmonary responses to CAPs emphasizes the need to conduct repeated studies, perhaps in relation to the season, as composition of CAPs may vary. Additionally, potential variability in pathology of induced bronchitis or other lung disease may decrease the ability to distinguish toxic injury due to PM.

Acetylglucosaminidase↗
PubMed2000

Induction of pulmonary matrilysin expression by combustion and ambient air particles.

The molecular mechanism(s) by which chemically complex air pollution particles mediate their adverse health effects is not known. We have examined the ability of combustion and ambient air particles to induce pulmonary matrilysin expression due to the well-documented role of matrix metalloproteinases in tissue injury and repair responses. Rats were exposed to saline, residual oil fly ash (2.5 mg/rat), or ambient air particles (2.5 mg/rat) via intratracheal instillation and examined 3-72 h after exposure. Saline-exposed animals had low levels of matrilysin mRNA, whereas the animals exposed to either complex particle showed an early induction of pulmonary matrilysin gene expression as well as of the 19-kDa activated form of matrilysin. Immunocytochemistry and in situ hybridization analyses identified the alveolar macrophages and monocytes as primary sources of air pollution particle-induced matrilysin expression. Matrilysin gene induction and protein activation by combustion and ambient air particles correlated with the early histopathological changes produced by these particles. These results demonstrate the ability of combustion and ambient air particles to induce pulmonary matrilysin expression and suggest a role for this matrix metalloproteinase in the initiation of lung injury produced by these particles.

Air Pollutants↗