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Biomedical subjects

M Williams

Publications and source records attributed to M Williams.

At least 235 records · Page 13Linked to original sources
PubMed1999

The impact of early onset otitis media on babbling and early language development.

Numerous studies have shown that otitis media (OM) during infancy has a negative impact on language development later in life. Few studies have examined the effect of OM on linguistic and prelinguistic behavior during infancy. The purpose of this study was to investigate the impact of OM on the development of canonical babble in children who experienced at least one episode during the period birth through 6 months of age, in comparison with children who did not experience OM during this period. The results show a consistently lower rate of canonical syllable production among children with early onset OM, when compared to children with later onset OM, during the period 6 through 18 months of age. In addition, a relationship between canonical babbling ability and expressive vocabulary size was observed at 18 months of age.

Female↗
PubMed1999

Perceptions of good medical practice in the NHS: a survey of senior health professionals.

OBJECTIVES: To categorize senior health professionals' experience with poor medical practice in hospitals and in general practice, to describe perceptions which senior NHS staff have of good medical practice, and to describe how problems of poor medical practice are currently managed. DESIGN: A postal questionnaire survey. The questionnaire sought perceptions of good medical practice, asked participants to characterise deviations from good practice, and to describe experience with managing poor performance at the time of the introduction of the General Medical Council (GMC) performance procedures. SETTING: A range of NHS settings in the UK: hospital trusts, health authorities/boards, local medical committees, community health councils. SUBJECTS: Senior health professionals involved in the management of medical professional performance. MAIN MEASURES: Perceptions of what constitutes good medical practice. RESULTS: Most respondents considered that persistent problems related to clinical practice (diagnosis, management, and outcome and prescribing) would require local management and, possibly, referral to the GMC performance procedures. Informal mechanisms, including informal discussion, education, training, and work shifting, were the most usual means of handling a doctor whose performance was poor. Many took a less serious view of deficiencies in performance on manner and attitude and communication, although consultation skills rather than technical skills comprised the greatest number of complaints about doctors. CONCLUSIONS: Senior NHS professionals seem reluctant to consider persistently poor consultation skills in the same critical light as they do persistently poor technical practice. These attitudes may need to change with the implementation of clinical governance and updated guidance from the GMC on what constitutes good medical practice.

Quality Assurance, Health Care↗
PubMed1999

A simple, inexpensive method for teaching how membrane potentials are generated.

We have developed a simple laboratory exercise that uses an inexpensive dialysis membrane (molecular weight cutoff = 100) to illustrate the generation of membrane potentials (Vm) across plasma membranes of animal cells. A piece of membrane approximately 2.0 cm2 is mounted in an Ussing-like chamber. One chamber half is designated cytosol and the other half external. Chamber sidedness helps students relate their findings to those of real cells. As in real cells, outward directed K+ concentration gradients [high cytosolic K+ concentration ([K+]c) and low extracellular K+ concentration] generate cytosol electrically negative Vm with a slope of approximately -45 mV/decade change in [K+]c. The polarity of Vm reflects the outward flow of potassium ions because flow of the larger counterion, H2PO4-, is restricted to the pores in the membrane. A slope less than Nernstian (<59 mV/decade) suggests that the membrane is slightly permeable to H2PO4-. Importantly, this facilitates teaching the use of the Nernst equation to quantify the relationship between ion concentration ratios across membranes and magnitude of Vm. For example, students use their data and calculate a permeability ratio PK/PH2PO4 that corresponds to a slope of approximately 24% less than Nernstian. This calculation shows that Nernstian slopes are achieved only when permeability to the counterion is zero. Finally, students use the concept of membrane capacitance to calculate the number of ions that cross the membrane. They learn where these ions are located and why the bulk solutions conform to the principle of electroneutrality.

Animals↗
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↗
PubMed1999

Supplementary oxygen and the laryngeal mask airway--evaluation of a heat-and-moisture exchanger.

Heat-and-moisture exchangers (HMEs) are routinely used in anaesthesia for the humidification and warming of inspired gases. The use of the Laryngeal Mask Airway (LMA) is widespread, and many anaesthetists choose to leave it in situ until the patient regains consciousness. In this study, we have investigated the effectiveness of an HME as a means of administering supplemental oxygen via LMA in the immediate postoperative period. Oxygen was administered at varying flow rates via the gas sampling port of the HME and the oxygen delivery recorded, using end-tidal oxygraphy as a measure of alveolar PO2. At an oxygen flow rate of 4 l.min-1, the HME provided a mean end-tidal oxygen concentration of 36.2% (+/- 6.2), which compares favourably to other previously described devices. The HME thus represents a convenient, effective and economical means of oxygen supplementation via the LMA.

Adolescent↗
PubMed1999

Isolation and characterization of novel human immunodeficiency virus integrase inhibitors from fungal metabolites.

We have identified a series of novel inhibitors of human immunodeficiency virus type 1 (HIV-1) integrase by randomly screening natural product extracts using an in vitro biochemical assay designed to identify inhibitors of integrase-catalysed strand transfer. Equisetin recovered from the fungus Fusarium heterosporum and a novel enantiomeric homologue of equisetin from Phoma sp. were isolated as inhibitors of HIV-1 integrase in vitro. Two additional analogues, a novel decalin derivative, integric acid, and oteromycin were also discovered to be inhibitors of integrase. Equisetin and related compounds inhibit 3' end-processing and strand transfer as well as disintegration catalysed by either the full-length enzyme or the truncated integrase core domain (amino acids 50-212). These compounds also inhibit strand transfer reactions catalysed by stable complexes assembled in vitro and integration reactions catalysed by pre-integration complexes isolated from HIV-1-infected cells. The compounds described in this report are structurally novel and mechanistically distinct from many previously described inhibitors of HIV-1 integrase. These results demonstrate the utility of using an appropriately configured assay to identify compounds that are effective post-assembly and the potential of isolating novel integrase inhibitors from complex natural product extracts.

Base Sequence↗
PubMed1999

Adherent and nonadherent medication-taking in elderly hypertensive patients.

Nonadherence to medications is a significant reason why patients fail to control their blood pressure. Little work has been attempted to conceptualize medication-taking behaviors from the patient's perspective. This study examined factors that influence elderly hypertensive patients' adherence or nonadherence to prescribed medications. Using a qualitative descriptive research design, 21 hypertensive elderly people were interviewed. Two domains of adherence were identified: purposeful use of the medication for the control of patient's blood pressure and establishing and maintaining patterns of medication-taking. Two similar domains also emerged for nonadherence: purposeful and incidental. Adherence behaviors were dependent on the person's decision to take hypertension medication, access to medications, and ability to initiate treatment and maintain a medication-taking pattern. The timing and location of pills were integral parts of establishing patterns of taking medications. Inadequate access to medications or interruption of a person's pattern were associated with the incidental missing of medications.

Aged↗
PubMed1999

Sensitivity of Shah, Vanclay and Cooper's modified Barthel Index.

OBJECTIVE: To investigate whether Shah, Vanclay and Cooper's modification of the Barthel Index improved its sensitivity to change. DESIGN: Correlational study. SETTING: School of Occupational Therapy at Auckland Institute of Technology, Auckland, New Zealand. SUBJECTS: One hundred subjects requiring rehabilitation following a stroke. MAIN OUTCOME MEASURES: Change in function which was measured using Shah, Vanclay and Cooper's (1989) modified Barthel Index and walking speed over 10 metres. RESULTS: Five statistical analyses were undertaken, none of which demonstrated clear superiority of one measure over the other. CONCLUSIONS: The study did not indicate the modified Barthel Index to be more sensitive to change than the 20-point Barthel Index for this population. The statistical analysis strategies utilized are recommended for similar studies.

Activities of Daily Living↗
PubMed1999

Teaching video effect on renal transplant patient outcomes.

A study was undertaken to test the effect of a teaching video on renal transplant recipient outcomes. A quasi-experimental, pretest/posttest design was used. Fifty-nine adults undergoing renal transplantation were studied. Subjects were randomly assigned to either an experimental group, which received discharge preparatory teaching with the use of a teaching video, or to a control group, which received standard teaching. Subjects in the experimental group had significantly greater improvements in knowledge scores postteaching. No other differences were seen. Findings suggest the use of a teaching video can be a useful adjunct to educational programs designed for renal transplant patients and their families.

Adult↗
PubMed1999

Does over-accomodation occur when using aircraft head-up displays?

BACKGROUND: Whether over-accommodation is caused by the use of head-up displays is still under debate. Most prior experimentation has involved cognitively demanding tasks, which are known to affect the accommodation response. The simulations have often been unrealistic and involved short working distances. HYPOTHESIS: Over-accommodation is caused not by the presence of a head-up display per se, but rather by the cognitive demand of the task. METHODS: The effect of increasing the task cognitive load and the use of forward looking infra-red imagery (FLIR) on the ocular accommodative response and task performance was assessed with a realistic head-up display assisted flying task. FLIR increases cognitive load due to its poor resolution and the need for interpretation of the images. RESULTS: Over-accommodation was found to be small in magnitude (0.17+/-0.03D; range -0.02-0.45D) occurring only with cognitively demanding tasks and with forward looking infrared imagery. Response times to detect tanks in the outside world scene were slower with increased cognitive load and forward looking infra-red imagery, along with a reduced detection rate, decreased accuracy of tracking tanks in the outside world and poorer control of the head-up display pitch ladder. When discrimination was added to detection in an outside world task, decisions were delayed until they could be accurately made, rather than performance degraded. CONCLUSION: The use of a virtual head-up display in a simulated aircraft environment did not adversely affect ocular accommodation. However, increased cognitive demand or FLIR imagery caused significant inward shifts of accommodation.

Accommodation, Ocular↗
PubMed1999

[The value of orbital ultrasonography in ethmoid sinusitis in children].

PURPOSE: To assess the value of orbital sonography (US) compared to CT in the management of children with ethmoid sinusitis. MATERIAL AND METHODS: A total of 13 consecutive patients admitted for non-complicated ethmoid sinusitis (absence of visual or neurological symptoms) were prospectively evaluated at US and CT. RESULTS: Three patients had no evidence of postseptal involvement at US. Ten patients had variable degree of postseptal involvement at US: hypoechoic area or fluid collection in the extraconal fat along the medial orbital wall. Results were confirmed at CT in all patients. CONCLUSION: US is useful to confirm the presence of postseptal involvement in patients with ethmoid sinusitis. Contrary to CT, findings at US remain non-specific as to the nature of involvement. Nonetheless, US is helpful for patient management.

Adipose Tissue↗
PubMed1999

The clinical effectiveness of a dentifrice containing triclosan and a copolymer for providing long-term control of breath odor measured chromatographically.

The objective of this double-blind clinical study was to investigate the effectiveness of a commercially available dentifrice containing triclosan and a copolymer (Colgate Total Toothpaste) for controlling long-term, i.e., seven-hour and overnight breath odor. In particular, a comparison was made between the level of control of breath odor provided by the test dentifrice, and that provided by a placebo dentifrice which did not contain triclosan or a copolymer. This study followed a two-treatment, two-period crossover design. Prospective subjects were provided with a supply of a commercially available fluoride dentifrice, which was used for a one-week period prior to the two seven-day treatment periods. During each treatment period, subjects were instructed to brush their teeth twice a day, morning and evening, for sixty seconds with their assigned study dentifrice, using the soft-bristled toothbrush which had been provided. On the morning following the seventh day of each treatment period, subjects reported to the clinical facility for overnight breath odor assessments. Directly following this, subjects brushed their teeth, ate and drank normally, and reported once again to the clinical facility at seven hours post-toothbrushing for another breath odor assessment. Prior to the overnight breath odor assessments, subjects refrained from brushing their teeth, rinsing their mouths or using breath mints, and from eating or drinking anything on the morning of the evaluation. Subjects refrained from the use of tobacco products, and from eating onions, garlic, or strong spices throughout the entire study. Breath odor was instrumentally evaluated by measuring the level of volatile sulfur compounds in the mouth air using a 565 Tracor gas chromatograph equipped with a flame photometric detector. Measurements were taken in duplicate, and then averaged. Levels of volatile sulfur compounds were expressed in nanograms per milliliter (ng/ml) of mouth air. The two dentifrices exhibited statistically significant differences (p < 0.05) with respect to both overnight breath odor and seven-hour post-toothbrushing breath odor. The mean overnight breath odor scores were 9.63 ng/ml for Colgate Total Toothpaste, and 12.64 ng/ml for the placebo dentifrice. For seven-hour breath odor, the mean scores were 5.62 ng/ml for Colgate Total Toothpaste, and 7.10 ng/ml for the placebo dentifrice. Thus, the results of this double-blind clinical study on 19 subjects support the conclusion that Colgate Total Toothpaste provides effective seven-hour and overnight control of breath odor.

Adult↗