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Biomedical subjects

A Stevens

Publications and source records attributed to A Stevens.

At least 307 records · Page 17Linked to original sources
PubMed1967

Effect of azasteroids on gram-positive bacteria.

A group of nitrogen-containing steroids closely related in structure was screened for antibacterial activity, by use of Bacillus subtilis and Sarcina lutea as the test organisms. The most active compounds were cholesterol derivatives containing a tertiary or quaternary nitrogen in, or attached to, the A ring. Similar methyltestosterone or progesterone derivatives were inactive. All of the cholesterol derivatives that inhibited growth were surfactant, and, structurally, they would be classified as cationic detergents. Some of the inactive compounds were surfactant, but, structurally, they would be classified as nonionic detergents. Certain features of the antibacterial activity of one of the active steroids-ND 212 (4-dimethylaminoethyl-4-aza-5-cholesten-3-one methiodide)-were studied. Growth of a culture of B. subtilis containing 5 x 10(7) cells per milliliter was inhibited by 1 mug/ml (1.7 x 10(-6)m) of ND 212. The amount of growth inhibition was directly related to both cell and steroid concentration. Loss of viability was rapid and irreversible. With B. subtilis, cell lysis was observed. With S. lutea grown in C(14)-glucose, ND 212 caused release into the media of up to 25% of the cellular radioactivity. Extensive leakage occurred before loss of viability was observed. At bacteriostatic azasteroid concentrations, there was little leakage. ND 212 was readily bound in large amounts to B. subtilis cells. Inactive azasteroids were bound poorly. C(14)-cholestanone was also bound, whereas C(14)-methyltestosterone and C(14)-progesterone were not bound in significant amounts. At least 50% of the bound C(14)-cholestanone was associated with the membrane fraction.

Bacillus subtilis↗
PubMedDate not supplied

Impact of the Minimum Pricing Policy and introduction of brand (generic) substitution into the Pharmaceutical Benefits Scheme in Australia.

PURPOSE: To describe the effects of introducing the Minimum Pricing Policy (MPP) and generic (brand) substitution in 1990 and 1994 respectively on the dispensing of Pharmaceutical Benefits Scheme (PBS) prescriptions both at the aggregate and individual patient level. METHODS: The relative proportion of prescriptions with a brand premium and those at benchmark was examined 4 years after introduction of the MPP and again 5 years later after generic substitution by pharmacists was permitted. To determine the impact of a price signal at the individual level, case studies involving a patient tracking methodology were conducted on two drugs (fluoxetine and ranitidine) that received a brand premium. RESULTS: From a zero base when the MPP was introduced in 1990, there were 5.4 million prescriptions (17%) dispensed for benchmark products 4 years later in 1994. At this stage generic (brand) substitution by pharmacists was then permitted and the market share of benchmark brands increased to 45% (25.2 million) by 1999. In the patient tracking studies, a significantly lower proportion of patients was still taking the premium brand of fluoxetine 3 months after the introduction of a price signal compared with patients taking paroxetine which did not have a generic competitor. This was also the case for the premium brand of ranitidine when compared to famotidine. The size of the price signal also had a marked effect on dispensing behaviour with the drug with the larger premium (fluoxetine) showing a significantly greater switch away from the premium brand to the benchmark product. CONCLUSIONS: The introduction in 1990 of the Minimum Pricing Policy without allowing generic substitution had a relatively small impact on the selection of medicines within the Pharmaceutical Benefits Scheme. However the effect of generic substitution at the pharmacist level, which was introduced in December 1994, resulted in a marked increase in the percentage of eligible PBS items dispensed at benchmark. Case studies showed a larger premium resulted in a greater shift of patients from drugs with a brand premium to the benchmark alternative.

Anti-Ulcer Agents↗
PubMedDate not supplied

Paranasal sinus mucormycosis in an immunologically competent host.

A case of paranasal sinus mucormycosis in an immunocompetent patient is reported. After an extensive evaluation, no evidence of either diabetes mellitus or underlying immunologic abnormality was found. The combination of excisional surgery and amphotericin B therapy resulted in an excellent response. High-resolution axial and coronal computed tomography was useful in both planning treatment and monitoring the response to therapy.

Adult↗
PubMedDate not supplied

A systematic review of the effectiveness of environmental awareness interventions.

PURPOSE: To evaluate and summarize evidence on the effectiveness of interventions available to public health staff regarding the protection of the public from environmental risks. METHOD: This systematic review involved a comprehensive literature search, screening for relevance, quality assessment of relevant studies, data extraction and synthesis. RESULTS: Fourteen of 65 relevant studies were of 'moderate' or 'strong' quality. Intervention types in these 14 studies included: mass campaign, counselling, school curriculum, educational sessions, and distribution of printed materials. Short-term improvements in awareness or knowledge were observed in 13 of the 14 studies. Eight of 13 studies that examined behavioural outcomes observed short-term improvements in self-reported behavioural outcomes. CONCLUSIONS: Positive short-term changes in health-protective awareness, knowledge and self-reported behaviour appear to be associated with relatively intensive interventions that use multiple methods and settings, and/or are delivered over multiple sessions.

Awareness↗
PubMedDate not supplied

Treatment of osteoarthritis of the hip and knee: a comparison of NSAID use in patients for whom surgery was and was not recommended.

OBJECTIVE: To determine if NSAID use was different between OA (hip and/or knee) patients treated surgically to those treated medically. METHODS: We conducted a case control study, in which cases (n = 433) had had a total joint replacement within a two-year period, while controls (n = 195) had seen a rheumatologist or orthopedic surgeon, and not been recommended for surgery. Current and previous NSAID use was surveyed. RESULTS: Cases were older than controls (70 vs. 64 years, p < 0.0001), and were more likely to have OA in the hips (45% vs. 21%, p < 0.0001), to have severe OA (p < 0.0001), and to be male (42% vs. 28%, p < 0.0008). Potential confounding variables were statistically adjusted using logistic regression. Although disease duration was similar in cases and controls (9.8 years), cases had tried fewer NSAIDs (1.3 +/- 0.05 vs. 2.3 +/- 0.08 in controls, p < 0.0001). Cases were less likely to have taken any NSAID (86% vs. 94% of controls; OR 0.40, p < 0.007) or to have had intra-articular steroids (OR 0.19, p < 0.0001). Two or more NSAIDs were used (ever) in 38% of cases vs. 70% of controls (p < 0.0001); and 3 or more NSAIDs in 5% vs. 38% (p < 0.0001). Women were less apt to have obtained total joint replacements (OR 0.62, p < 0.0001), including TKRs even when adjusting for severity of OA. CONCLUSIONS: NSAIDs are used less by orthopedic surgeons than rheumatologists in our centre. Some subjects were offered a joint replacement without even a failure of medical management. The reasons for differences in prescribing trends are unknown. Referral biases may exist.

Aged↗