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Biomedical subjects

S R Walker

Publications and source records attributed to S R Walker.

At least 73 records · Page 4Linked to original sources
PubMed1982

Ion beam etching effects in biological microanalysis.

Oxygen ion beam sputter etching used in SIMS has been shown to produce morphologic effects which have similarities and differences in comparison to rf plasma etching of biological specimens. For example, selective retention of nuclear and plasma membranes is observed in both cases, however, heterochromatin is preferentially sputtered by O2+ bombardment in SIMS and preferentially preserved during O2 plasma etching. Sputter yield variations resulting from structural microheterogeneity are illustrated (e.g. etch-resistant nucleoli in preferentially etched nuclei), including their impact upon ion image formation in an ion microanalyzer. These image artifacts must be evaluated before secondary ion images revealing subcellular organelles can be related quantitatively to elemental localization in cells or tissues. To minimize gross surface roughness effects such as cone formation induced by ion bombardment, ion imaging studies of thin sections using low primary ion doses are indicated.

Animals↗
PubMed1981

A clinical comparison of topical clobetasone butyrate and sodium cromoglycate in allergic conjunctivitis.

Clobetasone butyrate (0.1%), a new topical corticosteroid eye preparation for the treatment of ocular inflammation, has been compared with sodium cromoglycate (2%) eye drops in thirty-nine patients experiencing allergic conjunctivitis during the hay fever season. In this double-blind, within-patient comparative study both preparations were effective in relieving the patients' symptoms of conjunctivitis. However, clobetasone butyrate was clinically more effective than sodium cromoglycate as determined by symptom score card analysis (P less than 0.01) and the patients' overall assessment of treatment (P less than 0.05). Patients' preference for the treatment of seasonal allergic conjunctivitis was markedly in favour of clobetasone butyrate (P less than 0.001).

Adolescent↗
PubMed1981

Experimental ulcerative herpetic keratitis. II. Influence of topical corticosteroid in immunised rabbits.

Since the great majority of patients possess immune response to herpes simplex virus (HSV), the influence of a topical anti-inflammatory corticosteroid (0.1% clobetasone butyrate) on ulcerative herpetic keratitis was studied in rabbits with a previous HSV skin infection (immunised) and compared with that in normal rabbits. Corticosteroid treatment had a much greater ulceration-exacerbating effect in immunised than in normal animals. On day 7 the mean area of ulceration in immunised rabbits were 3 times greater in treated eyes. 0.01% clobetasone butyrate treatment had less effect on immunised rabbits; 0.001% had no effect. It is concluded that the immunised rabbit provides a useful experimental model for studying the relationship between concentration of topical anti-inflammatory agents and enhancement of herpetic ulceration.

Animals↗
PubMed1981

Clinical evaluation of clobetasone butyrate eye drops in the treatment of anterior uveitis and its effects on intraocular pressure.

Clobetasone butyrate has been formulated as a new steroid preparation of use in ophthalmology and has been compared with prednisolone phosphate and betamethasone phosphate in the treatment of anterior uveitis. The results from 4 double-blind, between-patient studies have shown that all 3 treatments are effective in reducing the signs and symptoms of this intraocular disease. 87% of those patients receiving clobetasone butyrate had a good or satisfactory response, but no differences in therapeutic efficacy were observed between these 3 steroid treatments. Clobetasone butyrate had little effect on intraocular pressure when compared with dexamethasone or hydrocortisone, both of which cause a significant rise in intraocular pressure.

Adolescent↗
PubMed1981

Clobetasone butyrate eye drops. Effect on ocular inflammation and intraocular pressure.

Clobetasone butyrate eye drops comprise a new steroid preparation which has been investigated in two comparable, double-blind, multicentre clinical trials in patients with ocular inflammation. One study compared clobetasone butyrate with betamethasone phosphate eye drops (205 patients) and the other study compared corresponding preparations containing neomycin (169 patients). There was no difference between the responses to clobetasone butyrate and betamethasone. An excellent or good response was obtained in 73 per cent of patients treated with clobetasone butyrate, 75 per cent with betamethasone, 69 per cent with clobetasone butyrate formulated with neomycin, and 76 per cent with betamethasone formulated with neomycin. Patients who were known to react with a rise of intraocular pressure (IOP) to steroids were treated with clobetasone butyrate eye drops in one eye and either prednisolone eye drops (6 patients) or hydrocortisone eye drops (4 patients) in the other eye. The doses were continued for 6 weeks, or less if the IOP rose more than 10 mm Hg in one eye. All patients experienced a greater intraocular pressure rise in the eye treated with prednisolone or hydrocortisone. The mean changes in IOP were 9 mm Hg for prednisolone compared to 2 mm Hg for clobetasone butyrate (P less than 0.05 Wilcoxon signed ranks test) and 16 mm Hg for hydrocortisone compared to 2 mm Hg for clobetasone butyrate.

Adolescent↗
PubMed1980

Clinical evaluation of clobetasone butyrate: a comparative study of its effects in postoperative inflammation and on intraocular pressure.

Clobetasone butyrate, a new corticosteroid with a high topical activity, has been compared with prednisolone phosphate and a placebo in the treatment of inflammation following cataract extraction. These 2 steroids were more effective in relieving postoperative inflammation than placebo (P less than 0.05), though no obvious clinical differences between the 2 compounds emerged from this investigation. However, a single-blind comparative study against betamethasone phosphate in patients suspected of having steroid-induced glaucoma showed that, while betamethasone phosphate significantly raised intraocular pressure, clobetasone butyrate had only a minimal effect, and this difference was statistically significant (P less than 0.02).

Administration, Topical↗
PubMed1980

Ion microanalysis of cells.

The application of ion microanalysis (IMA) to the chemical characterization of freeze-fixed, freeze-dried cells is reviewed. Particular emphasis is given to pathological studies involving the determination of the chemical composition of isolated cells (e.g. rabbit alveolar macrophages--RAMs) exposed in vitro to toxic species (e.g. Pb3O4 particles). Ion microscopic results indicated that lead from Pb3O4 migrated into the RAMs and subsequently formed phosphorous-containing compounds. Quantitative comparisons of the relative concentrations of physiologic elements in Pb3O4-treated versus control RAMs also were made using ion microanalytical techniques. The Pb3O4 results illustrate that the three-dimensional analysis capabilities of the IMA may be exploited for the in situ observation of the penetration of xenobiotic agents into cell interiors and their subsequent intracellular chemistry. The potential advantages of ion microanalysis for the characterization of cells include high elemental sensitivity (including low atomic number elements and diffusible ions), broad elemental coverage, three dimensional analysis, and isotopic information. The major limitations include non-idealities of the ion sputtering process, the constraints on the lateral resolution available to identify subcellular features, and the difficulties inherent in the determination of absolute elemental concentrations.

Animals↗
PubMed1979

The intraocular penetration of cefuroxime after parenteral administration.

Cefuroxime (Zinacef) is a new second generation cephalosporin which is resistant to beta-lactamases produced by both Gram-negative and Gram-positive organisms, with an antibacterial spectrum that includes practically all likely ocular pathogens except pseudomonas. It is shown to penetrate into the eye after intravenous (1.5g) or intramuscular (1 g) injection and achieve therapeutic concentrations, with absence of side effects. Cefuroxime is therefore a useful antibiotic for ophthalimic infections and should have a role in combination with gentamicin in intraocular infections, particularly those of unknown aetiology.

Adult↗
PubMed1978

Dealing confidently with IRS, Part I: Preparing for IRS audits.

With the IRS apparently making health care institutions the focus of a nationwide audit emphasis, hospital administrators will want to prepare themselves for confident handling of audits. Four types of audit procedures are explained, suggestions are made for getting a hospital ready for an audit, and strategies are suggested for maintaining control over the audit's progress.

Accounting↗
PubMed1977

The combined use of betamethasone valerate and sodium cromoglycate in the treatment of asthma.

A double-blind comparison of betamethasone valerate, sodium cromoglycate and the combination of these two treatments was carried out in twenty-two adult patients with asthma. Regular fortnightly assessments were made in the clinic throughout the study and adrenal function was monitored and found to be normal. All patients measured their peak expiratory flow rates in the morning and evening and monitored their symptoms daily on a record card as well as recording bronchodilator usage. Assessment using these parameters indicated that treatment with betamethasone valerate compared with sodium cromoglycate resulted in an improvement in the patients' asthma which was stitistically significant (P less than 0-001). Overall the combined treatment produced a better response than sodium cromoglycate (P less than 0-02) but a poorer response compared with the steroid aerosol given alone (P greater than 0-05). In only two patients was the response to the combined therapy significantly greater than to either drug given alone.

Adolescent↗
PubMed1976

A clinical study of the prophylactic use of betamethasone valerate and sodium cromoglycate in the treatment of seasonal allergic rhinitis.

The prophylactic use of betamethasone valerate and sodium cromoglycate in seasonal allergic rhinitis has been investigated in 20 patients in an open study. The subjective assessment of the symptoms recorded on a daily record card was significantly lower in the betamethasone valerate group compared with the sodium cromoglycate group. Patients' and physician's overall assessment of the treatment favoured the steroid aerosol. No clinically significant side effects were noted.

Aerosols↗