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Biomedical subjects

A R Brown

Publications and source records attributed to A R Brown.

At least 37 records · Page 2Linked to original sources
PubMed1997

Tetrafluoroethane (HFC 134A) propellant-driven aerosols of proteins.

PURPOSE: Develop metered-dose propellant-driven aerosols of proteins using tetrafluoroethane (HFC 134A) as propellant. METHODS: Proteins were lyophilized with the propellant-soluble surfactants Triton X-100, Triton X-405, Laureth-9, Brij-30, Nonidet-40, and diethylene glycol monoethylether and then charged with propellants. RESULTS: Small particle aerosols of the experimental protein bovine gamma globulin were produced. The fraction of aerosolized respirable-sized protein particles (< 4-5 microns) increased after dispersion of particles in propellant with agitation by shaking. Scanning electron microscopy of respirable-sized protein aerosols demonstrated bead-like particles in grape-like clusters. Vigorous shaking of propellant-suspended particles for 2 minutes or more reduced the size of clusters and reduced the diameters of the protein-containing subparticles that constituted the clusters. A 50:50 ratio of HFC 134A and dimethylether (DME) propellants improved the respirability of protein aerosols compared to HFC 134A as the sole propellant. Protein/surfactant particles first dispersed in DME and then diluted in HFC 134A propellant most efficiently produced respirable-sized, propellant-driven, protein aerosols.

Aerosol Propellants↗
PubMed1997

Injuries sustained by caregivers of disabled elderly people.

OBJECTIVE: to investigate the occurrence of physical injury experienced by informal caregivers whilst moving and lifting their disabled elderly dependents at home. DESIGN: a descriptive study using in-depth interviews. SETTING: departments of elderly medicine at two teaching hospitals and one district general hospital. SUBJECTS: 46 informal caregivers of elderly patients admitted under a regular hospital respite care scheme, 41 of whom were interviewed. RESULTS: most caregivers were elderly (median age 70 years), 21 having a medical condition which restricted their physical activity. Thirty one caregivers had injured themselves whilst lifting and handling their dependents. Most sustained back injuries. Eight caregivers were temporarily unable to continue caring as a result of the injuries they sustained. Sixteen patients had been injured whilst being moved by their caregivers. Only 19 caregivers had received instruction in manual handling. CONCLUSION: informal caregivers are often poorly trained and equipped and at risk of injury. To enable them to continue providing optimal care at home, their physical health should be assessed and they should be trained in safe lifting and handling techniques.

Adult↗
PubMed1997

Effects of tetracycline hydrochloride and chlorhexidine gluconate on Candida albicans. An in vitro study.

This study examined the effects of tetracycline hydrochloride (TCN) and chlorhexidine gluconate (CHX) on the growth and viability of Candida albicans. Subcultures of Candida albicans on Sabouraud's agar, were divided into 5 treatment groups: group 1, untreated control; group 2, 0.12% CHX; group 3, 3.0 mg/ml TCN adjusted to pH 4.5; groups 4 and 5, sodium azide free Tris buffer adjusted to pH 4.5 and pH 7.4, respectively. All groups were incubated for 10 days, and sampled and subcultured daily to determine the viability of each group. Additional samples from group 2 (day 4), group 4 (day 7) and all groups at day 10 were selected for SEM and TEM examination. Visual, SEM and TEM results showed that for groups 1, 3, 4, and 5 there was a heavy and constant uniform growth of Candida albicans throughout the period of the study. However, group 2 (CHX), showed decreasing viability and attachment from day 3 to day 10, with SEM and TEM revealing decreased blastospores and profound changes in the ultrastructural morphology, indicating inhibition of normal cell growth and replication. These results show that TCN even when used at high concentrations, in vitro, will allow uninhibited growth of Candida albicans whereas CHX inhibits cell growth and replication.

Adhesiveness↗
PubMed1997

Do it yourself: home-made aids for disabled elderly people.

We contacted the caregivers of patients admitted on a hospital respite care scheme and asked them about home-made or modified aids and appliances. Seven home-made devices were discovered and inspected. They were an electric hoist, a builder's plastic skip used as a bath, a wheelchair support and tray made out of chipboard, stair rails made from old steel pipe, an improvised commode and a modified standard commode enabling the user to be cleaned in the sitting position. Several gadgets were innovative; others were dangerous. Two caregivers had injured themselves using the improvised aids. Others were at risk of injury. With an increasing tendency for Community Agencies to charge for equipment, more caregivers may design and build their own aids-some of which may be hazardous. Health professionals who visit elderly people at home should look for home-made gadgets with a view to promoting safety and discovering innovations which may help others.

Activities of Daily Living↗
PubMed1997

An uplifting experience? Hospital passenger lifts and their suitability for disabled people.

Hospitals should be welcoming places, and disabled people should not expect difficulties when using a hospital's facilities. For some elderly and disabled people the passenger lift may be the only means of vertical movement within a building. We visited four hospitals and inspected their passenger lifts for use by disabled and elderly people. We compared our findings with those of an "ideal lift' drawn from recommendations by disabled support groups, National Health Services Estates Department and building regulations. We found that most hospital passenger lifts are inadequate for those with mobility, visual and hearing impairments. Consequently, disabled and elderly people might have problems using hospital passenger lifts, with a subsequent loss of independence. The provision of well-designed and accessible passenger lifts is central to imaginative hospital building design.

Persons with Disabilities↗
PubMed1997

Atypical palatal papillomatosis treated by excision and full-thickness grafting.

Papillary lesions of the oral cavity are extremely common, and inflammatory palatal hyperplasia is well known to dental practitioners. Advanced sophistication in viral laboratory technologies makes it apparent that various forms of the human papilloma virus are often causative. However, this is not true for inflammatory palatal hyperplasia. This article describes a patient with anatomically well-demarcated, multiple squamous cell papillomas of the palate that could not be classified as inflammatory palatal hyperplasia, nor could a viral etiology be ascertained, despite exhaustive laboratory studies. The lesion recurred despite numerous surgical ablation attempts. Eradication was achieved only after applying free soft-tissue grafts over the areas of excision. The differential diagnosis of papillary lesions with an emphasis on viral etiology, laboratory studies associated with their identification, and a hypothesis that explains why grafting was the only successful means of treatment are also discussed.

DNA Probes, HPV↗
PubMed1996

Cellulitis and the occult diabetic.

BACKGROUND: Occult diabetes may be an important factor in the development of cellulitis and cellulitis may act as a precipitant to the diagnosis of diabetes mellitus. The present study defines the prevalence of diabetes and glucose tolerance impairment in a group presenting with cellulitis to a teaching hospital. A description of the demographic and pathological presentation of the group is undertaken. METHODS: Five hundred consecutive admissions for cellulitis to a Sydney teaching hospital were analysed. The cases presented between 1985 and 1994. Precipitating factors, length of stay, site of infection, white cell count, degree of fever, blood sugar estimation, history of diabetes mellitus and microbiological diagnosis were recorded. RESULTS: Forty-nine patients had a prior diagnosis of diabetes mellitus. Twenty-one percent of patients (56/265) were noted to have abnormal glucose tolerance on routine testing. Thirty-seven per cent of the 1994 cohort (14/38) demonstrated abnormal glucose tolerance. The most common precipitant was trauma (137/500). Mean length of stay was 8.7 days. Microbiological diagnosis was made in 32% of cases. CONCLUSIONS: Cellulitis requiring admission to hospital is a significant problem in terms of cost and bed occupation. A presentation with cellulitis may be a clinical indicator of impaired glucose tolerance. All patients presenting with cellulitis should have a fasting blood sugar level determined as part of routine workup.

Adult↗
PubMed1996

Effectiveness of a prescale gel on subgingival calculus.

A prescale gel product, designed to facilitate the removal of calculus, has recently been introduced and marketed to the dental profession. The purpose of this study was to evaluate the effectiveness of this gel on the removal of subgingival calculus. 10 patients, each with 5 periodontally diseased teeth scheduled for extraction, participated in this in vivo/in vitro study. 4 teeth per patient were randomly assigned using a 2-by-2 block design and treated in vivo with either active or placebo gel, with or without scaling, prior to extraction. To assess possible overexposure to the product, 10 selected teeth from the sample were treated with active gel for an extended exposure time. Standardized scaling was performed on a 4x4 mm treated root area in vitro on groups as assigned. Quantification of residual calculus was determined by one examiner blind to treatment group assignment using SEM photomicrograph montages and the Java image analysis computer system. Repeated measures ANOVA showed no statistically significant treatment effect for gel (p > 0.05) in the scaled and no-scaled groups. The 5th group exposed to the prescale gel for an extended time was evaluated descriptively for root surface morphological changes with no noticeable effect. Based on the results of this investigation, treatment of subgingival calculus with prescale gel offers no advantage for calculus removal over scaling alone. The findings suggest no significant clinical impact of product use.

Adult↗
PubMed1996

Congestive cardiac failure following laxative withdrawal.

We report the case of a 60-year-old woman who presented with weakness and hypokalaemia due to excessive use of laxatives. When the laxatives were withdrawn, she developed severe congestive cardiac failure requiring treatment with a diuretic and angiotensin-converting enzyme inhibitor. There was no underlying cardiac abnormality, and these drugs were eventually stopped with no recurrence of the cardiac failure. The possible mechanisms of heart failure following laxative withdrawal is discussed.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1996

Radiological evaluation of the interfaces after cemented total hip replacement. Interobserver and intraobserver agreement.

Three radiological methods are commonly used to assess the outcome of total hip replacement (THR). They aim to record the appearance of lucent areas and migration of the prosthesis in a reproducible manner. Two of them were designed to monitor the implant through time and one to grade the quality of cementing. We have measured the level of inter- and intraobserver agreement in all three systems. We randomised 30 patients to receive either finger packing or retrograde gun cementing during Charnley hip replacements. The postoperative departmental radiographs were evaluated in a blinded study by two orthopaedic trainees, two consultants and two experts in THR. The trainees and consultants repeated the exercise at least two weeks later. We used the unweighted kappa statistic to establish the levels of agreement. In general, intraobserver agreement was moderate but interobserver agreement was poor, with levels similar to or less than those expected by chance. Our results indicate that such systems cannot provide reliable data from centres in different parts of the world, with various levels of surgeon evaluating radiographs at differing time intervals. We discuss the problem and suggest some methods of improvement.

Bone Cements↗
PubMed1996

Air contamination during skin preparation and draping in joint replacement surgery.

Despite the use of ultraclean air, there are still cases of infection in total joint arthroplasty. One possible route by which bacteria may enter the wound is indirectly by contamination of instruments during skin preparation and draping. We found that bacterial air counts were 4.4 times higher during preparation and draping for hip or knee arthroplasty using an unscrubbed, ungowned leg holder than during the operation itself. With the leg holder scrubbed and gowned during preparation and draping, the air counts were reduced but were still 2.4 fold greater than intraoperatively. On some occasions, the air counts during preparation and draping exceeded the standards for ultraclean air irrespective of the attire of the leg holder. We recommend that the leg is held by a scrubbed and gowned member of the team. More importantly, we consider that instrument packs should be opened only after skin preparation and draping have been completed.

Air Microbiology↗
PubMed1995

Propellant-driven aerosols for delivery of proteins in the respiratory tract.

Metered-dose propellant-driven aerosols of an antigenically reactive protein were produced by combining bovine gammaglobulin (BGG) with one of several surfactants soluble in Freon or dimethylether propellants. Small-particle protein aerosols were most effectively produced by lyophilizing surfactants and proteins prior to the addition of propellants. Up to 26% of the total aerosolized protein was of respirable size. Aerosol metering valves delivering small volumes were most effective in producing respirable-sized (< or = 4 micron median mass aerodynamic diameter) protein aerosols. Proteins were suspended in liquified propellants as both propellant-soluble molecules and visible sedimenting clusters which both contributed to making respirable-sized protein aerosol particles. Electron microscopy showed that respirable-sized protein particles were composed of variable-sized chain aggregates of spherical subunits. Proteins were antigenic after suspension in liquified propellant and release as aerosols, but antigenicity diminished with extended propellant exposure. Local immunity in the respiratory tract is a key factor in resistance to respiratory infections. Metered-dose propellant-driven aerosols offer a potentially attractive method for delivering small-particle aerosols of immunizing antigens or other therapeutic proteins to the respiratory tract.

Aerosol Propellants↗
PubMed1994

Chamber for testing metered-dose propellant-driven aerosols of immunologically relevant proteins.

A small aerosol chamber was developed for testing and delivery of aerosols of immunologically important proteins to the respiratory tracts of rodents. The chamber was designed to accommodate the small aerosol volumes produced by metered-dose propellant-driven aerosol canisters. Metered bursts of protein aerosols released into the chamber could be sampled for their particle sizes or used to expose the noses of up to six mice to the aerosols. The chamber consisted of a polyethylene tank with two removable plexiglass end plates. One end plate accommodated the propellant-driven, metered-dose, aerosol vial. The other end of the tank was fitted with a plate accepting aerosol sampling devices or a plate containing mouse restrainers. Uniform concentrations of aerosolized proteins were obtained at different positions in the chamber when sampled for particles of respirable size. Respirable-sized protein particles produced by propellant-driven aerosols ranged from 5 to 50% of total aerosolized protein. Propellant-driven aerosols of proteins released in the chamber produced aerosol particles equivalent to 15-26 micrograms of total protein exposure to the respiratory tract of each mouse. The chamber permitted aerosol releases without risk of operator exposure. This aerosol chamber will permit the testing of protein aerosols for their immunologic consequences to the respiratory tract. Potential proteins for testing in this device include immunizing vaccine antigens, immunomodulating cytokine proteins, and passive antibody aerosol therapies against respiratory infections.

Aerosols↗
PubMed1994

Pharmacokinetics and pharmacodynamics of a new cardiotonic vasodilator agent, 349U85, in normal subjects.

OBJECTIVE: To assess the pharmacodynamics and pharmacokinetics of single oral doses of a new vasodilator-cardiotonic agent, 349U85 hydrochloride [6-piperidino-2(1H)-quinolinone hydrochloride], in healthy male subjects. METHODS: This randomized, parallel, double-blind, placebo-controlled, dose escalation trial was conducted at a university-based clinical research center among 27 healthy male subjects. Data measurements used in the study included cardiac index, supine and standing blood pressure, 24-hour ambulatory electrocardiography, and 12-lead electrocardiography. RESULTS: Doses from 2 mg to 250 mg were well tolerated. Cardiac index, supine heart rate, and orthostatic hypotension, indicators of inotropic, chronotropic, and vasodilator effects, respectively, correlated to plasma concentrations of 349U85 and of its metabolite, 661U88. Results suggest that 349U85 may be more responsible for inotropic effects, whereas 661U88 may be more responsible for vasodilatory and chronotropic effects. These results are consistent with the preclinical pharmacologic profile for these two compounds. Headache, orthostatic dizziness, and hypotension tended to occur more frequently at higher doses and were temporally related to drug administration. Pharmacokinetic analyses indicate nonlinearity of 349U85 and 661U88, suggestive of saturation of metabolism and large interindividual variability in maximum plasma drug concentration and area under the plasma concentration-time curve. The source of the variability is not known. The time to maximum distribution was approximately 0.7 hours for both 349U85 and 661U88; the terminal elimination half-life was 1 hour for 349U85 and 3 hours for 661U88. Holter monitoring revealed asymptomatic increases in ventricular and supraventricular ectopic activity in some volunteers; ectopy appeared to be related to the dose of 349U85 and generally occurred at higher doses.

Adult↗
PubMed1993

Interscalene block for shoulder arthroscopy: comparison with general anesthesia.

Arthroscopic shoulder surgery can be performed under regional or general anesthesia. The objective of this study was to demonstrate that regional anesthesia has several benefits over general anesthesia for this type of surgery, particularly in the ambulatory patient. Forty patients received general anesthesia and 63 an interscalene block. The regional block was found to be safe and effective, with a high degree of patient acceptance. It provided excellent intraoperative analgesia and muscle relaxation. Postoperatively, regional anesthesia resulted in fewer side effects, fewer hospital admissions, and a shorter hospital stay than did general anesthesia.

Adolescent↗
PubMed1993

Laparoscopic management of acute small bowel obstruction.

Acute small bowel obstruction is commonly due to band adhesions. In the past it has had an overall mortality rate of up to 11% for elderly patients. In this paper we report three cases of small bowel obstruction, treated by laparoscopic division of the causative bands. All patients recovered rapidly and were discharged within 5 days of surgery.

Acute Disease↗