The physical properties of a polyacetal denture resin

A polyacetal injection-moulded resin is being marketed for the construction of retentive and supportive components of removable partial dentures (RPDs). Specimens of poly(oxymethylene) cast by commercial laboratories were tested to examine the following physical characteristics: the modulus of elasticity in compression, extension and flexure, stress relaxation, the force displacement behaviour of clasp forms, impact strength and glass transition temperature. Results showed that the material has a flexural modulus lower than that of poly(methylmethacrylate) and is insufficiently rigid to be used as a supporting element for partial dentures. Resin clasps may be resilient enough to engage undercuts for the retention of RPDs but the low flexural modulus requires that the resin be used in greater cross-sectional area than metal alloys in order to gain useful retention. This greater bulk has implications for plaque accumulation and maintenance of periodontal health.     

Diagnosis and treatment of risk factors in Germany and the UK

Objective

To estimate the impact of different systems of family practitioners’ payment on process of care: fee-for-service vs. capitation.

Design

Cross sectional international survey using cardiovascular prevention as an indicator of the quality of care.

Setting

Family physicians’ practices in Germany (fee-for-service) and the UK (capitation).

Subjects

778 patients attending for consultation regardless of morbidity or risk factor status.

Main outcome measures

Intervals since last consultation, since last BP-measurement, prevalence of known hypertension.

Results

There is a higher overall level of activity under FFS, but under capitation FPs seem to concentrate their efforts on the more severely ill or at risk. This would explain that under different systems of remuneraton the quality of care (outcome) is usually similar.

Conclusions

In areas of uncertainty FFS seems to stimulate activity or intervention, whereas under capitation FPs are rather reluctant to engage in procedures or interventions that are not sufficiently evaluated. Under prepaid remuneration FPs adjust in a way that the quality of care does not suffer.     

Proteolytic maturation of transforming growth factor-α

Summary Transforming growth factor- (TGF-) is a mitogenic peptide hormone produced extracellularly, by tumor cells, and by virally and chemically transformed cells in culture. TGF- is almost certainly derived from its precursor protein (pro-TGF-) by limited endoproteolysis, but physiologically relevant processing enzyme(s) of the pro-TGF- protein and the cellular or subcellular compartment in which processing takes place are not known with certainty. We previously detailed [Cappelluti, E. and Harris, R.B., Biochemistry, 32 (1993) 551] the discovery, characterization and purification of novel, elastase-like enzymes (molecular weight 38 000) from oncogenically transformed rat liver epithelial cells or cultural Schwann cells transfected with SV40-large T antigen. The elastase-like enzyme appeared to be specifically induced in the transformed epithelial cells compared with the level of enzyme in the nontransformed parental cells. In the intervening time, other elastase-like serine proteinases have been implicated in processing pro-TGF- in other human carcinoma cell lines. We now report that the elastase-like enzymes, purified from transformed Schwann or liver epithelial cells, are inhibited in a time- and concentration-dependent fashion with three differently substituted monocyclic -lactam-based compounds originally developed as specific inhibitors of polymorphonuclear leukocyte elastase, thus further supporting the elastase-like character of the putative pro-TGF- processing enzymes. We also report the presence of the elastase-like enzyme in two different human malignant mammary cell lines, but even though MCF-7 cells receiving high doses of radiation in vitro show an increased level of expression of TGF-, the elastase-like enzyme does not appear to be induced in these cells following irradiation.     

A comparative study of etching enamel by acid and laser

Acid etching is regarded as one of the main means of providing additional retention in aesthetic dentistry. Alternative methods of achieving bonding to tooth tissue which have been proposed include laser etching. Conflicting results on bond strength to enamel have been reported for laser etching. Here the tensile bond strength of composite resin to acid- and laser-etched enamel was measured and the topographical differences between the surfaces were evaluated using the scanning electron microscope. The laser used was a pulsed Nd-YAG laser at 10 pulses per second with a pulse length of 150s, 80mJ pulse^–1, 1.064m wavelength. The results obtained indicate that the bond strength of laser-etched enamel was significantly lower than that of acid-etched enamel. In this study the difference may be attributable to the chromophore used. Variations in the rate of traverse of the laser tip across the surface did not appear to produce significant alterations in the bond strength.     

Responsibilities and resources of on-call public health doctors

We investigated the resource available for public health doctors to carry out statutory responsibilities out-of-hours by a postal questionnaire survey of consultants in communicable disease control (CsCDC) in England and Wales. The questionnaire requested details of local District Health Authority (DHA) population profile, major incident and outbreak policies, the background of the CCDC, out-of-hours communication, access and resources, reference materials and medical equipment carried by the public health doctor on duty. The CsCDC from 96% (121/126) DHAs in England and Wales responded. Whilst 85% (101/119) of public health doctors carried policies on infectious disease when on duty, only 28% (32/116) carried policies on dealing with chemical incidents and 25% (28/111) carried the District policy to deal with radiation hazards. Twenty-six per cent (32/121) of public health physicians had no access to their District headquarters. There is a wide variation in the standard of resources available to on-call public health doctors in England and Wales; following Department of Health and Department of the Environment guidance, Health Authorities need to ensure that they have adequate arrangements in the event of any major incident or outbreak.     

Intraoperative assessment of acute hemodynamic changes after partial left ventriculectomy

Partial left ventriculectomy (PLV) has been introduced as an alternative surgical therapy for patients with end-stage dilated cardiomyopathy. The physiological benefits of PLV are relatively unknown. Therefore, the objective of this study was to determine the acute effects of PLV by measuring cardiac function before and after PLV. Aortic and left ventricular pressures and aortic flow were measured in eight patients. Continuous, beat-to-beat data were recorded and compared pre-PLV and post-PLV with and without inferior vena cava (IVC) occlusions. PLV increased cardiac output (0.93+/-0.5, p = 0.01) as a result of increased stroke volume (5.12+/-4.24, p = 0.06) and heart rate (14.5+/-8.44, p = 0.02). Contractility (+/- dP/dt, 240.33+/-74.28, p = 0.001) and external work (650.8+/-320.4, p = 0.01) were also improved. Left ventricular end-diastolic elastance (0.15+/-0.14, p = 0.10) nearly doubled after PLV. Our results indicated an improved cardiac function as measured by increased cardiac output, stroke volume, ejection fraction (EF), and contractility.     

Optic nerve edema as a consequence of respiratory disease

The authors describe a patient with bilateral papilledema, visual field abnormalities, poorly reactive pupils, meningeal enhancement on cranial MRI, and diffuse brain parenchymal hypervascularity. The opening pressure at the time of lumbar puncture was normal, and results of other CSF studies were normal. All abnormalities resolved with home oxygen therapy.     

Distribution of 5-hydroxytryptamine-immunoreactive boutons on immunohistochemically-identified Renshaw cells in cat and rat lumbar spinal cord

A combination of anti-gephyrin- and anti-calbindin D28k-immunoreactivity was used to identify 129 and 171 Renshaw cells and their dendrites in cat and rat lumbar spinal cord, respectively. Using anti-5-hydroxytryptamine-immunoreactivity to label serotoninergic fibers and boutons, 1048 serotoninergic boutons were observed in close contact with the immunolabeled Renshaw cells, with an average of 4.4 and 2.8 close contacts on cat and rat Renshaw cells, respectively. Two-thirds of the observed appositions were formed on the somatic membrane.     

Designing an intervention to prevent suicide: PROSPECT (Prevention of Suicide in Primary Care Elderly: Collaborative Trial)

Suicide is a major public health problem with greatest risk in the very old. This paper describes an approach to reducing the risk of suicide by intervening on depression in elderly primary care patients. Depression is an appropriate target for an intervention as it is highly prevalent in primary care, is a strong risk factor for suicide, and is more often than not inadequately treated. PROSPECT (Prevention of Suicide in Primary Care Elderly: Collaborative Trial) is a National institute of Mental Health (NIMH)-funded collaborative study that is testing this approach to suicide risk prevention in 18 primary care practices in the United States. PROSPECT'S intervention of "guideline management" introduces a health specialist into the primary care setting to help physicians provide "on-time, on-target" treatment and long-term management of late-life depression following structured clinical guidelines. The effectiveness of the intervention in reducing suicidal risk and depression is evaluated by following a representative sample of older patients identified using a 2-stage design.