Cytocompatibility of novel tin oxide thin films

The capacity of tin oxide films to support cell growth was investigated. Three substrates were used for the test: glass coverslips, glass coverslips spin coated with tin oxide and commercially available 316 stainless steel. The wettabilities and surface roughness of the three surfaces were measured before seeding 3T3 fibroblasts onto the samples. The behaviour of the cells grown on the tin oxide was compared to the uncoated glass and the steel and results showed that the cell growth on tin oxide compared favourably with the other substrates. The surface wettability appeared to have the strongest effect on cell adhesion to tin oxide.

Multiple-quantum MAS NMR of quadrupolar nuclei. Do five-, seven- and nine-quantum experiments yield higher resolution than the three-quantum experiment?

The question of whether or not higher-order (five-, seven- and nine-quantum) multiple-quantum magic angle spinning (MQMAS) experiments yield isotropic NMR spectra of half-integer quadrupolar nuclei with higher resolution than the basic three-quantum MAS experiment is examined. The frequency dispersion is shown theoretically to be greatly increased in higher-order MQMAS spectra, but it is argued that whether or not this translates into an increase in resolution depends upon the ratio of the homogeneous to inhomogeneous contributions to the isotropic linewidth. Experimentally, it is demonstrated using three-, five- and seven-quantum 45Sc MAS NMR and three- and five-quantum 27Al MAS NMR of crystalline samples that higher-order MQMAS experiments can yield a real and useful increase in resolution but that, owing to the presence of inhomogeneous broadening in the isotropic spectra, this increase is less than the theoretically predicted value. A number of practical issues relating to resolution in MQMAS NMR are also pointed out.

Plasma and vessel wall lipoprotein lipase have different roles in atherosclerosis

Lipoprotein lipase (LPL) is a key enzyme in lipoprotein metabolism, and has been hypothesized to exert either pro- or anti-atherogenic effects, depending on its localization. Decreased plasma LPL activity is associated with the high triglyceride (TG);-low HDL phenotype that is often observed in patients with premature vascular disease. In contrast, in the vessel wall, decreased LPL may be associated with less lipoprotein retention due to many potential mechanisms and, therefore, decreased foam cell formation. To directly assess this hypothesis, we have distinguished between the effects of variations in plasma and/or vessel wall LPL on atherosclerosis susceptibility in apoE-deficient mice. Reduced LPL in both plasma and vessel wall (LPL(+/-)E(-/-)) was associated with increased TG and increased total cholesterol (TC) compared with LPL(+/+)E(-/-) sibs. However despite their dyslipidemia, LPL(+/-)E(-/-) mice had significantly reduced lesion areas compared to the LPL(+/+)E(-/-) mice. Thus, decreased vessel wall LPL was associated with decreased lesion formation even in the presence of reduced plasma LPL activity. In contrast, transgenic mice with increased plasma LPL but with no increase in LPL expression in macrophages, and thus the vessel wall, had decreased TG and TC and significantly decreased lesion areas compared with LPL(+/+)E(-/-) mice. This demonstrates that increased plasma LPL activity alone, in the absence of an increase in vessel wall LPL, is associated with reduced susceptibility to atherosclerosis. Taken together, these results provide in vivo evidence that the contribution of LPL to atherogenesis is significantly influenced by the balance between vessel wall protein (pro-atherogenic) and plasma activity (anti-atherogenic).

The influence of hospital-based prescribers on prescribing in general practice

OBJECTIVE

To document the influence of hospital prescribers on prescribing in general practice.

DESIGN AND PARTICIPANTS

Five percent of members of the Irish College of General Practitioners (n = 92) prospectively recorded 40 consecutive prescriptions.

INTERVENTIONS

The name, dose and amount of medicine prescribed as well as the indication for therapy, details of their practice, distribution of private/GMS patients, and the number of years since qualification were recorded. The cost of individual prescriptions was calculated based on the ingredient cost and the number of days of treatment. This was subsequently correlated with the origin of the prescription. Each prescription was classified as either new or repeat.

MAIN OUTCOME MEASURES AND RESULTS

Of 3286 prescriptions, 69% were for the state-supported General Medical Services (GMS) patients and 31% for private patients. Repeat prescriptions constituted 51%; 49% were new prescriptions. While hospital doctors initiated only 8% of private prescriptions, they initiated 38% of GMS prescriptions, particularly repeat prescriptions and those for cardiovascular, hormonal and centrally-acting agents. Prescriptions for anti-infectives, oral contraceptives, dermatological preparations and musculoskeletal drugs were mostly initiated in general practice. The median cost for hospital-initiated GMS prescriptions (5.93 Pounds) was greater than the cost of general practitioner (GP)-initiated prescriptions (3.49 Pounds; p < 0.01). Prescriptions from GPs who were qualified for less than 10 years and those with a mixed urban and rural practice were less costly (p < 0.05) than those issued by doctors qualified for over 10 years or working predominantly in an urban or rural area. These findings may also reflect differences in patient population, morbidity and demography.

CONCLUSIONS

Our study indicates that hospital-initiated prescriptions are responsible for a significant proportion, both in volume and cost of GP prescribing.

Accessible dental care for children

The development of a school-based comprehensive and cost-efficient oral health care program requires careful planning centered on the needs expressed by the community. Gaining the support and the cooperation of school officials and parents creates an environment that has a significantly greater opportunity for success. Location, appropriate design of the facility and support from a local charitable organization further insure excellent access and expeditious care.

Prosocial self-schemas, self-awareness, and children's prosocial behavior

Three studies examined the hypothesis that a child's prosocial self-schema predicts prosocial behavior. In Study 1, only self-aware boys showed a self-schema-behavior relation. Study 2 altered both salience of donating opportunity and relationship of recipient to donor. The hypothesized Self-Awareness x Self-Schema interaction was significant, and there were no gender differences. Study 3 systematically manipulated the salience of the donating opportunity. All participants were self-aware. For boys in high and low salience conditions, prosocial self-schema predicted donating behavior. For girls, prosocial self-schema predicted behavior only in the high salience condition. The findings demonstrate that self-schemas can regulate behavior when participants are self-aware. Girls, however, may require higher salience of the donating opportunity for the self-schema to affect their behavior.

Low rate of generic prescribing in the Republic of Ireland compared to England and Northern Ireland: prescribers' concerns

We compared the level of generic prescribing in the Republic of Ireland, Northern Ireland and England and surveyed the views of Irish College of General Practitioners members. In 1993, generic drugs (pure generics and branded generics together) comprised 17.4% of total dispensing in the General Medical Services Scheme, significantly less than Northern Ireland or England where pure generics alone comprised 25% and 38% respectively of total dispensing in the National Health Services. General practitioners accurately self-estimated their level of generic prescribing but are concerned about the reliability/quality of generic products on the market, possible legal liabilities associated with their use and the fact that pharmacists may legally dispense more expensive proprietary preparations in the case of private prescriptions written generically. Prescribers need reassurance regarding legal and quality assurance aspects of generic prescribing if the level of generic drug use is to increase.

A standardised breakfast tolerance test in pregnancy: comparison with the 75 g oral glucose tolerance test in unselected mothers and in those with impaired glucose tolerance

There is still disagreement concerning the optimal procedure for the diagnosis of milder degrees of hyperglycaemia in pregnancy. We have compared the results of a 75 g oral glucose tolerance test (OGTT) and a standardised breakfast test performed one week apart in 102 non-diabetic women with a singleton pregnancy. There was poor correlation between the two tests (r = 0.15) at two hours, and neither test was predictive of adverse maternal or fetal outcome. One hundred and four patients with impaired glucose tolerance, diagnosed at 30 weeks' gestation by 75 g OGTT, subsequently had a breakfast and lunch meal profile. There was no significant correlation between the two-hour OGTT value and either the two hour post-breakfast value (r = 0.35) or the maximum profile value (r = 0.33). Using the WHO diagnostic criterion of > 8 mmol/l for the OGTT and a maximum glucose concentration > 6.8 mmol/l for the meal profile, there was no relationship between an abnormal result in either test and pregnancy outcome. In our obstetric environment, the 75 g OGTT, a standardised breakfast test, and a structured meal profile, all failed to provide a useful indication of pregnancy outcome in mothers not already known to have diabetes.

The topology of transcription by immobilized polymerases

Current models for RNA synthesis involve an RNA polymerase that tracks along a static template. However, research on chromatin loops suggests that the template slides past a polymerase immobilized in a large transcription factory. The evidence for immobilized polymerases is reviewed, and a model for transcription by such fixed enzymes is presented. According to the model, gene activation would involve reducing gene-factory distance and increasing the affinity of a promoter for a factory. Locus controlling regions and enhancers would attach to a factory and increase the chances that a promoter could bind to a polymerase; after transcriptional termination, the gene would detach from the factory. As some RNA processing occurs cotranscriptionally, processing sites are also likely to be associated with the factory.

The effect of various oestrogens and progestogens on the susceptibility of low density lipoproteins to oxidation in vitro

OBJECTIVE

To investigate the effect of different oestrogens and progestogens, at various concentrations, on the oxidation of low density lipoproteins (LDL) in vitro.

METHODS

Oestradiol, oestrone, oestriol and equilin, as well as medroxyprogesterone acetate, norgestrel and norethisterone, were added to isolated male LDL, before it was oxidised in the presence of copper ions at 37 degrees C. The oxidation process was monitored spectrophotometrically by the production of conjugated dienes. The lag time to oxidation and the maximum rate of propagation of the reaction were used as measures of the resistance and susceptibility of the LDL to oxidation respectively.

RESULTS

The lag time was increased from 43.7 +/- 1.5 min (mean +/- SEM) for LDL without any added hormone, to 81.2 +/- 1.0 min by 1 microM oestradiol (P < 0.01), 77.9 +/- 4.6 min by 1 microM oestrone (P < 0.01), 67.6 +/- 6.2 min by 1 microM equilin (P < 0.01), and 51.8 +/- 2.8 min by 1 microM oestriol (P < 0.05). The maximum rate of propagation of the reaction was decreased from 0.23 +/- 0.01 nmol conjugated dienes/mg LDL-protein/min (mean +/- SEM) (control LDL) to 0.14 +/- 0.006 nmol/mg/min by oestradiol (P < 0.01), 0.15 +/- 0.009nmol/mg/min by oestrone (P < 0.01), 0.17 +/- 0.012 nmol/mg/min by equilin (P < 0.01) and 0.19 +/- 0.014 nmol/mg/min (P < 0.05) by oestriol. The progestogens alone had no antioxidant effect, nor did their addition to the oestrogens influence their antioxidant activity.

CONCLUSIONS

These results demonstrate that all oestrogens investigated have an inhibitory effect on LDL oxidation in vitro. The magnitude of this effect varied, being of the order oestradiol > oestrone > equilin > oestriol.

On the structure of replication and transcription factories

Recent experiments suggest that active polymerases are concentrated in large structures, 'factories', within eukaryotic nuclei. Data concerning the structure of these factories is reviewed.