Public perceptions of the role of Australian pharmacists in cardiovascular disease.

BACKGROUND AND OBJECTIVE: To assess the public's perception of pharmacists' involvement and role in cardiovascular disease prevention and management. METHODS: A computer-assisted telephone interview of 505 households was conducted. The survey was administered to metropolitan, rural and remote residents over the age of 30 years. The interview had questions on the patient's general satisfaction with the quality of service provided by their regular community pharmacy, including factors such as location, professionalism, prices, product range and knowledge of the staff. The participants were asked if they thought pharmacists were capable of providing screening, testing and drug prescribing services for blood pressure and cholesterol, and how likely they would be to use these services through a pharmacy. The interview also included questions on how likely this person would be to seek advice on lifestyle changes and medications from various health professionals, including pharmacists. RESULTS: The majority (97%) were satisfied with the service provided at their regular pharmacy. Those surveyed agreed or strongly agreed that pharmacists are capable of providing screening or testing for raised blood pressure (52%) and diabetes (51%), with a minority (38%) agreeing that pharmacists are capable of testing for raised cholesterol. The pharmacist's role with perceived highest capability by those surveyed was in providing advice on how to take medicines properly, with 90% of respondents willing to seek this advice from their pharmacist. A limited role by pharmacists was seen in the diagnosis of CVD and prescribing medications. In relation to the prevention of CVD, even though 76% of respondents believed that pharmacists are capable of providing advice on lifestyle changes (e.g. weight loss, smoking and alcohol intake), only 8% of current or past smokers had sought assistance to give up smoking at their pharmacy and while 69% of all respondents had sought help with weight control, only 3% of these had looked towards their pharmacy for assistance. CONCLUSION: There was belief by those Australians surveyed that community pharmacists are capable of providing screening for hypertension and diabetes. Through these services and in conjunction with counselling on CVD risk reduction, pharmacists may play an important role in the reduction of CVD, ultimately improving public health and decreasing the burden on Australia's health care system. However, at present pharmacists are not being fully utilized to deliver health promotion advice and contribute to the prevention of CVD.

Oral contraceptive effects on food choice during the follicular and luteal phases of the menstrual cycle. A laboratory based study.

Fifty-five women were recruited and assigned to a control group or an oral contraceptive (OC) use group. For the control groups menstrual cycle phase was determined using a menstrual calendar and only participants with regular cycles were recruited. Testing was carried out during a single day of the luteal and follicular phases, where participants were asked to consume and rate sweet and savoury snacks. Participants in the OC group were tested on the equivalent days of their pill calendar. In both groups, the luteal phase induced a greater caloric intake of sweet foods without altering hedonic ratings. No significant interactions between either phase or flavour with OC use on food intake or hedonic food ratings were found. At least for snack items, OC do not seem to alter the caloric intake fluctuations that occur during a normal menstrual cycle.

The effect of nicotinamide on spontaneous and induced activity in smooth and skeletal muscle.

BACKGROUND AND PURPOSE: Nicotinamide (NA) is currently undergoing clinical trials as a tumour radiosensitizer. The dose that can be administered is currently 80 mg/kg per day, but this may be restricted to 60 mg/kg per day by the high incidence of nausea and vomiting. To investigate some of NA's underlying mechanisms of action, we have used an ex vivo system to study the direct effect of this drug, over a wide range of concentrations, on isolated spontaneously active rat ileum. Effects on the gut were compared with the action of NA on skeletal and vascular smooth muscle. MATERIALS AND METHODS: Isolated rat ileum rings were perfused with oxygenated Krebs' solution in an organ bath. NA (1 microM to 10 mM) was introduced to the perfusate and the change in amplitude of spontaneous peristaltic activity recorded. Dissected frog sartorius muscle was bathed in modified oxygenated Ringer's solution in an organ bath. The muscle was electrically stimulated to generate isometric contractions. Tension was then measured before and after the addition of a range of NA concentrations (8.2-24.6 mM) to the organ bath. RESULTS: NA inhibited peristalsis in the ileum in a dose-dependent manner. At a drug concentration of 1 mM the amplitude of contractions was reduced to <50% of the initial control value. NA had no effect on the electrically induced contractions in the isolated frog sartorius muscle. CONCLUSIONS: Gut smooth muscle is highly sensitive to the relaxant effect of NA producing 50% relaxation at a concentration approximately 10 fold lower than that required in rat arterial smooth muscle, while having no effect on non-mammalian skeletal smooth muscle. This may provide explanations for the occurrence of emesis in patients undergoing combined nicotinamide therapies and highlight possible alternatives available to counter this unwanted side-effect.

Estimate of the molecular weight of the sarcolemmal sodium channel using H2O-D2O centrifugation.

The sodium channel saxitoxin binding component from rat sarcolemma was solubilized with NP-40 and centrifuged on sucrose gradients constructed in either D2O or H2O. When compared with a series of standard proteins the sedimentation behavior of the solubilized channel complex changed from an apparent S20,w of 9.1 in H2O to 6.1 in D2O. From these observations, a true partial specific volume of 0.83 ml/g was calculated for the complex. A Stokes radius of 8.6 nm was estimated from Sepharose 6-B chromatography in NP-40. The calculated protein molecular weight of the lipid-protein-detergent complex based on these data is 560,000. The complex contains about 56% protein, and the calculated molecular weight of this component is 314,000 if a v for the protein of 0.74 ml/g is assumed.

Size characteristics of the solubilized sodium channel saxitoxin binding site from mammalian sarcolemma.

The sodium channel saxitoxin binding component from rat sarcolemma was solubilized with medium chain length non-ionic detergents including NP-40, Brij-96 and Lubrol-PX. Phospholipid was required for stability of the binding component. Specific saxitoxin binding was significantly temperature sensitive even with optimal levels of phospholipid present. The solubilized saxitoxin binding component chromatographed on Sepharose 6B at a position corresponding to that of a globular protein of 95--10 A Stokes radius, but had an apparent s20,w typical of a smaller molecule (s20,w = 9.2--10). Column behavior and s20,w were independent of the specific detergent used for solubilization. Anomalous column behavior may reflect molecular asymmetry, contribution from bound detergent or similar considerations.

Purification from rat sarcolemma of the saxitoxin-binding component of the excitable membrane sodium channel.

The saxitoxin-binding component (SBC) of the excitable membrane sodium channel has been solubilized and purified from rat skeletal muscle sarcolemma. Phospholipid was required in mixed micelles with detergent for stability of the mammalian SBC. Even at optimal detergent-to-phospholipid ratio, the solubilized SBC showed significant temperature-dependent loss of specific toxin binding with time, necessitating maintenance of low temperatures during purification. Characteristics of saxitoxin binding to the solubilized material closely resembled those seen in intact membranes. A weak anion-exchange column was synthesized; it provided rapid 10- to 20-fold purification of the solubilized SBC. Additional necessary purification was obtained by chromatography on immobilized wheat germ agglutinin. Specific saxitoxin-binding activity of the purified material averaged approximately 1500 pmol of saxitoxin bound per mg of protein. Three bands were present in this material on sodium dodecyl sulfate/polyacrylamide gel electrophoresis. The purified material sedimented on a sucrose gradient with an apparent s20,w of 9.9 S.

Muscle surface membranes: preparative methods affect apparent chemical properties and neurotoxin binding.

Considerable disagreement exists between results reported by various authors for lipid composition and enzyme activity in purified muscle membrane fractions presumed to be sarcolemma, although an explanation for these discrepancies has not been presented. We have prepared muscle light surface membrane fractions of comparable density (1.050--1.120) by a low-salt sucrose method and by an LiBr-KCl extraction procedure and compared them for density profile, total lipid and cholesterol content, protein composition and ATPase activity. In addition, sodium channels characteristic of excitable membranes have been quantitated in each preparation using [3H]saxitoxin binding assays, and the density of acetylcholine receptors determined in fractions from control and denervated muscle using alpha-[125I]bungarotoxin. Although both fractions contain predominantly surface membrane, the LiBr fraction consistently shows the higher specific activity of p-nitrophenylphosphatase, higher free cholesterol content, and higher density of sodium channels and acetylcholine receptors. The density distribution of sodium channels appears uniform throughout both fractions. Quantitative differences were seen between sodium dodecyl sulfate polyacrylamide gel electrophoresis patterns of membrane proteins from the two preparations although most bands are represented in both. A majority of the low-salt sucrose light membrane proteins were accessible in varying degrees to labelling with diazotized diiodosulfanylic acid in intact muscle. These results suggest that light surface membrane fractions may be mixtures of sarcolemma and T-tubular membranes. Using our preparative methods, the LiBr fraction may contain predominantly sarcolemma while low-salt sucrose light membranes may be enriched in T-tubular elements.