A comparison of the shear bond strength of composite resin bonded by a fourth and a fifth generation dental adhesive to bovine teeth

AIM

This study compared the shear bond strengths, to bovine enamel and dentine, of composite resin bonded using an established bonding agent (Syntac) and the more recent Syntac SC.

METHOD

A total of 24 adult bovine incisors were divided into two equal groups and prepared by roughening the enamel surfaces with a medium-grit, high-speed diamond. The enamel was etched and 24 x 5 mm diameter composite discs were light-cured and bonded using Syntac and 24 using Syntac SC, following the manufacturer's instructions. The samples were shear tested 72 hours later at a crosshead speed of 50 mm/min using a Howden Universal Testing Machine. The labial enamel and 1 mm of dentine were removed and the experiment was repeated.

RESULTS

The mean shear bond strengths (MPa) for the Syntac and Syntac SC bonded composite to enamel were 10.9 +/- 4.5 and 8.9 +/- 5.7, and to dentine 6.4 +/- 3.2 and 5.5 +/- 3.1, respectively. The differences between the values for each material on enamel and between each material on dentine were not significant (P > 0.01). However, nine (19%) Syntac SC bonded composite discs debonded during build-up and had to be remade, prior to testing.

CONCLUSION

When a bond between composite and resin was achieved, no significant difference was found between the mean shear bond strengths of Syntac and Syntac SC bonded composite to either enamel or dentine. However, lack of composite adherence to the Syntac SC was noted during the preparation of specimens.

The brain-pituitary-gonadal axis of female rainbow trout Oncorhynchus mykiss: effects of photoperiod manipulation1

Two groups of post-spawned female rainbow trout were exposed to two different photoperiods, an ambient photoperiod (56 degrees N) and a combination of long and short photoperiods (a constant 18L:6D from February 1 until May 10, then a constant 6L:18D), which acted to advance maturation and spawning. The stimulatory long-short photoperiod advanced spawning by 3-4 months and correspondingly advanced peaks in serum levels of 17beta-estradiol, testosterone, calcium (an index of vitellogenin), and GTH II. Earlier events in gonadal recrudescence appeared to be less affected by the photoperiod. The initiation of exogenous vitellogenesis coincided with high levels of both pituitary salmon gonadotropin-releasing hormone (sGnRH) content and serum follicle-stimulating hormone (FSH, GTH I) levels. High levels of serum FSH were associated with rapid gonadal growth in the fish exposed to the stimulatory long-short photoperiod. In contrast, the fish exposed to the ambient photoperiod showed gonadal steroid production, formation of vitellogenin, and secondary oocyte growth without any detectable increase in serum FSH levels. The possible roles and interactions of sGnRH, gonadotropins, and steroids with respect to normal and artificially stimulated ovarian maturation are discussed.

Peripheral thrombolysis for acute-onset claudication. Thrombolysis Study Group

BACKGROUND

The aim of this study was to determine the outcome of patients who presented with sudden onset of incapacitating claudication of less than 2 weeks' duration and who were treated with peripheral arterial thrombolysis.

METHODS

The database of the Thrombolysis Study Group was searched retrospectively for patients who received thrombolysis for acute-onset claudication. Some 108 patients (65 men, median age 69 (range 29-94) years) were treated with intra-arterial tissue plasminogen activator at 14 hospitals. The median duration of symptoms was 72 h (range from 2 h to 2 weeks). There were 52 graft and 56 native vessel arterial occlusions.

RESULTS

The immediate outcome of thrombolysis for native vessel arterial occlusion was thrombus clearance in 50 patients (89 per cent) and failed lysis in six (11 per cent). Thirty-six patients (64 per cent) had a secondary radiological or surgical procedure carried out after lysis. After 30 days four patients (7 per cent) had a major amputation, eight (14 per cent) had died, 38 (68 per cent) were symptom free and seven (12 per cent) continued to have claudication. Three patients (5 per cent) suffered a major haemorrhage. The immediate outcome of thrombolysis for graft occlusion was thrombus clearance in 48 patients (92 per cent) and failed lysis in four (8 per cent); 27 patients (52 per cent) had a secondary procedure. After 30 days four patients (8 per cent) had a major amputation, seven (13 per cent) had died, 32 (62 per cent) were symptom free and nine (17 per cent) had persistent claudication. Three patients (6 per cent) suffered a major haemorrhage.

CONCLUSION

Patients who presented with acute onset of incapacitating claudication had an outcome similar to that after thrombolysis for critical ischaemia. It is recommended that patients who present in this way should be observed and treated with thrombolysis only if they progress to critical ischaemia. Presented to the Association of Surgeons of Great Britain and Ireland, Edinburgh, UK, May 1998, and published in abstract form as Br J Surg 1998; 85(Suppl 1): 24

Vascular surgical society of great britain and ireland: first year of a fast-track carotid duplex service

BACKGROUND: The risk of a major stroke after a transient ischaemic attack (TIA) is highest in the first 3 months after the onset of symptoms. Urgent endarterectomy in appropriate cases is recommended through a fast-track one-stop assessment clinic. METHODS: Local general practitioners (GPs) were informed that a duplex scan would be guaranteed within 14 days of referral of any patient who had a recent clearly documented TIA or amaurosis fugax. Referral letters were faxed and the scan was authorized by a consultant surgeon. Those with significant disease were seen in the clinic in preparation for operation. Non-significant results were conveyed by post to the GPs with no further action. RESULTS: In the first 12 months of the service, 90 scans were performed through the fast track. In the same interval 490 non-fast-track scans were done after request by a physician (38 per cent), geriatrician (24 per cent), neurologist (14 per cent), vascular surgeon (11 per cent), ophthalmologist (8 per cent) or others (4 per cent). Thirteen (14 per cent) of 90 patients in the fast-track group had carotid endarterectomy, with a median period between referral and operation of 30 (range 20-45) days and median time between onset of symptoms and surgery of 7 (range 4-58) weeks. Endarterectomy was carried out in 12 (2 per cent) of 490 patients in the routine group with a median duration between referral and operation of 127 (range 64-184) days. CONCLUSION: A fast-track service can significantly reduce the time between referral and operation, and increase the number of endarterectomies. Urgent and appropriate referral from the GPs is vital for the service to work efficiently.

Decreased chronotropic drive as an adaptation to chronic exercise; possible mechanisms

Cardiovascular function was determined at rest and during exercise in twenty-eight healthy, elite distance runners. Maximum heart rate was 184 +/- 6 b x min(-1), which was more than one SD lower than the age predicted value (p < 0.001), and an inverse correlation was observed between maximum heart rate and VO2max (r = - 0.82, p < 0.001). The most aerobically trained athlete, a 27 year old male, presented with a maximum heart rate of 139b x min(-1). Echo-cardiac ultrasound revealed unremarkable intra-cardiac dimensions and flow characteristics relative to other endurance-trained athletes. A decreased chronotropic drive may represent a favourable physiological adaptation to endurance exercise which increases cardiovascular efficiency.

Stripping the long saphenous vein reduces the rate of reoperation for recurrent varicose veins: five-year results of a randomized trial

OBJECTIVE

The purpose of this study was to investigate the possible long-term clinical advantages of stripping the long saphenous vein during routine primary varicose vein surgery.

METHODS

The study was designed as a 5-year, clinical and duplex scan follow-up examination of a group of patients who were randomized to stripping of the long saphenous vein during varicose vein surgery versus saphenofemoral ligation alone. The study was conducted in the vascular unit of a district general hospital. One hundred patients (133 legs) with uncomplicated primary long saphenous varicose veins originally were randomized. After invitation 5 years later, 78 patients (110 legs) underwent clinical review and duplex scan imaging.

RESULTS

Sixty-five patients remained pleased with the results of their surgery (35 of 39 stripped vs 30 of 39 ligated; P = .13). Reoperation, either done or awaited, for recurrent long saphenous veins was necessary for three of 52 of the legs that underwent stripping versus 12 of 58 ligated legs. The relative risk was 0.28, with a 95% confidence interval of 0.13 to 0.59 (P = .02). Neovascularization at the saphenofemoral junction was responsible for 10 of 12 recurrent veins that underwent reoperation and also was the cause of recurrent saphenofemoral incompetence in 12 of 52 stripped veins versus 30 of 58 ligated legs. The relative risk was 0.45, with a 95% confidence interval of 0.26 to 0.78 (P = .002).

CONCLUSION

Stripping reduced the risk of reoperation by two thirds after 5 years and should be routine for primary long saphenous varicose veins.

Poor outcome in patients aged over 80 with limb-threatening ischaemia

The aim of this study was to determine the outcome in a consecutive series of patients over 80 years of age with limb-threatening ischaemia. The authors performed a retrospective case-note review of the treatment and outcome in 108 patients with 131 episodes of leg ischaemia, who presented to a vascular unit between 1992-1996 inclusively. Some 73 (56%) episodes of leg ischaemia occurred in patients suitable for active treatment (limb salvage 75%, amputation 4% and death 21%). Results were inferior in patients not actively treated (limb salvage 19%, amputation 50% and death 31%). Elderly patients not selected for active treatment have a very poor outcome and are seldom mentioned in publications. In future, clinical reports should include actively treated and rejected patients to avoid selection bias. Research should focus on the selection process and alternative therapies.

Comparing parent loss with sibling loss

The death of a loved one is a traumatic loss for children, but little attention has been paid to how children's responses vary according to who died--a parent or a sibling. This article reports the findings of a comparison between children's responses to parent and sibling loss. Two samples of bereaved children were combined for the project, which compared children's scores on the Achenbach Child Behavior Checklist. Findings indicated that there were no significant differences between the two loss groups in the total number of problems, in any of the syndrome scales, or in the percentage of children at risk. However, when the two loss groups were considered by gender, differences appeared--boys were more impacted by the loss of a parent than by the loss of a sibling and girls were most affected by the loss of a sibling, particularly a sister. Possible explanations for these differences are discussed.

DNA binding and dimerisation determinants of Antirrhinum majus MADS-box transcription factors

Members of the MADS-box family of transcription factors are found in eukaryotes ranging from yeast to humans. In plants, MADS-box proteins regulate several developmental processes including flower, fruit and root development. We have investigated the DNA-binding mechanisms used by four such proteins in Antirrhinum majus, SQUA, PLE, DEF and GLO. SQUA differs from the characterised mammalian and yeast MADS-box proteins as it can efficiently bind two different classes of DNA-binding site. SQUA induces bending of these binding sites and the sequence of the site plays a role in determining the magnitude of these bends. Similarly, PLE and DEF/GLO induce DNA bending although the direction of the resulting bends differ. Finally, we demonstrate that the MADS-box and I-domains are sufficient for homodimer formation by SQUA. However, the K-box in SQUA can also act as an oligomerisation motif and in the full-length protein, the K-box plays a different role in mediating dimerisation in the context of SQUA homodimers or heterodimers with PLE. Together these results contribute significantly to our understanding of the function of SQUA and other plant MADS-box proteins at the molecular level.

Evaluating the use of Snoezelen and chronic pain: the findings of an investigation into its use (Part II)

This is the second of two papers which describes a research project which was designed to evaluate the use of Snoezelen for the management of chronic pain. Part I explored the concepts underpinning both chronic pain and the Snoezelen itself which subsequently resulted in the development of an appropriate study design. The purpose of the study was to compare the use of Snoezelen for the management of chronic pain as a potential relaxation and distraction strategy, compared to the traditional relaxation approach used within the clinic. This paper will present the results that were obtained with the research project and in the light of these findings the author will discuss implications for future investigation and practice.

Blood lipid and lipoprotein concentrations in active, sedentary, healthy and diseased men

AIM

To examine differences in resting blood lipid and lipoprotein concentrations in male subjects of varying degrees of cardiovascular fitness ranging from the healthy elite athlete to the sedentary subject either with or without angiographically confirmed evidence of coronary artery disease (CAD).

METHODS

Two-hundred-and-eighty-four clinically asymptomatic male subjects were selected from a group of Olympic distance runners (n = 1 7), physical education athletes (n = 44), and industrial executives (n = 223). Each subject received a detailed physical examination and provided a venous blood sample after fasting, which was analysed for lipid and lipoprotein concentrations. Maximum oxygen uptake was determined using on-line computerised respiratory analysis during a functional diagnostic test. The industrial executive group was further divided according to their electrocardiographic (ECG) response to exercise; negative ECG (n = 138), positive (abnormal) ECG but no angiographic evidence of CAD (n = 18) and positive ECG with angiographic evidence of significant CAD (n=67).

RESULTS

Lipid-lipoprotein profiles were consistently abnormal in subjects with a positive ECG and documented evidence of CAD, whereas those subjects who tested negative or false-positive were less affected. The lipid-lipoprotein profiles observed between Olympic distance runners and an age-matched group of physically active students were not significantly different despite clear differences in physical activity patterns.

CONCLUSIONS

In addition to the abnormal lipid-lipoprotein profile in subjects with CAD, the present data also suggest that while physical activity confers metabolic cardioprotection, a threshold stimulus exists beyond which no further benefits can be gained.

Experiences of mothers in five countries whose child died of cancer

Although increasing attention is being focused on the emotional aspects of caring for dying children and their families, few research reports concentrate on the experiences of mothers, particularly in different countries. This article describes the findings of an exploratory, descriptive study that investigated the experiences of mothers from five different countries who each had a child die from cancer in the past 6 months. Principal investigators, members of the International Work Group on Death, Dying, and Bereavement, conducted semistructured interviews with 21 mothers in their own countries. No culturally related differences were noted among mothers, and the mothers' recall of their experiences are more similar than different. All mothers, irrespective of country, described similar reactions to the diagnosis, management of the end-stage illness, and challenge of coping with bereavement. Lessons learned from this project provide suggestions for future research across countries.

Early results of a randomized trial of rifampicin-bonded Dacron grafts for extra-anatomic vascular reconstruction. Joint Vascular Research Group

BACKGROUND

The aim of this study was to determine whether the routine use of an antibiotic-bonded gelatin-coated Dacron graft could reduce the incidence of prosthetic graft infection. Extra-anatomic grafts were chosen for study as they have the highest risk of graft infection. This paper reports early results up to 1 month after surgery.

METHODS

This multicentre study involved 14 vascular units in the UK. A total of 257 patients underwent extra-anatomic bypass. Patients were randomized to rifampicin bonding (1 mg/ml rifampicin soak for 15 min before graft insertion) or a control group. Routine three-dose antibiotic prophylaxis was administered to patients in both groups.

RESULTS

There were 178 men and 79 women of median age 69 (range 43-92) years. Rifampicin-bonded (n=123) and control (n=134) groups were well matched for clinical details, risk factors and operative techniques. No side-effects were noted from rifampicin bonding. Only one patient (in the control group) developed a graft infection and this proved fatal. There were no significant differences between bonded and unbonded grafts in terms of perioperative mortality rate (9 and 5 per cent respectively), median hospital stay (10 days for both groups), total infective complications (15 and 21 per cent respectively) or need for postoperative antibiotics (13 and 18 per cent respectively).

CONCLUSION

Early results from this study have not identified any significant advantage in the routine use of rifampicin bonding, but the rate of graft infection was very low (0.4 per cent). Gelatin coating alone may provide protection against infection. Definitive recommendations about the role of antibiotic bonding cannot be made until longer follow-up becomes available.

Implications of moderate altitude training for sea-level endurance in elite distance runners

Elite distance runners participated in one of two studies designed to investigate the effects of moderate altitude training (inspiratory partial pressure of oxygen approximately 115-125 mmHg) on submaximal, maximal and supramaximal exercise performance following return to sea-level. Study 1 (New Mexico, USA) involved 14 subjects who were assigned to a 4-week altitude training camp (1500-2000 m) whilst 9 performance-matched subjects continued with an identical training programme at sea-level (CON). Ten EXP subjects who trained at 1640 m and 19 CON subjects also participated in study 2 (Krugersdorp, South Africa). Selected metabolic and cardiorespiratory parameters were determined with the subjects at rest and during exercise 21 days prior to (PRE) and 10 and 20 days following their return to sea-level (POST). Whole blood lactate decreased by 23% (P < 0.05 vs PRE) during submaximal exercise in the EXP group only after 20 days at sea-level (study 1). However, the lactate threshold and other measures of running economy remained unchanged. Similarly, supramaximal performance during a standardised track session did not change. Study 2 demonstrated that hypoxia per se did not alter performance. In contrast, in the EXP group supramaximal running velocity decreased by 2% (P < 0.05) after 20 days at sea-level. Both studies were characterised by a 50% increase in the frequency of upper respiratory and gastrointestinal tract infections during the altitude sojourns, and two male subjects were diagnosed with infectious mononucleosis following their return to sea-level (study 1). Group mean plasma glutamine concentrations at rest decreased by 19% or 143 (74) microM (P < 0.001) after 3 weeks at altitude, which may have been implicated in the increased incidence of infectious illness.

Computer assisted knee replacement

Accurate alignment of knee implants is essential for the success of total knee replacement. Although mechanical alignment guides have been designed to improve alignment accuracy, there are several fundamental limitations of this technology that will inhibit additional improvements. Various computer assisted techniques have been developed to examine the potential to install knee implants more accurately and consistently than can be done with mechanical guides. For example, computer integrated instrumentation incorporates highly accurate measurement devices to locate joint centers, track surgical tools, and align prosthetic components. Image guided knee replacement provides a three-dimensional preoperative plan that guides the placement of the cutting blocks and prosthetic components. Robot assisted knee replacement allows one to machine bones accurately without the use of standard cutting blocks. The rationale for the development of computer assisted knee replacement systems is presented, the operation of several different systems is described, the advantages and disadvantages of different approaches are discussed, and areas for future research are suggested.

Palliative care at home: reflections on HIV/AIDS family caregiving experiences

This study explored the day-to-day experiences of family members providing care at home for their dying loved one with HIV/AIDS. In-depth interviews with seven caregivers were analyzed using grounded theory qualitative methods. A conceptualization of the family caregiving experience portrays HIV/AIDS caregiving as an intense, emotional, and powerful experience filled with pride and enrichment, and conversely, with anger and disillusionment. Findings reflected a significant need for interventions designed to provide direct and effective support for family members caring for a loved one with HIV/AIDS.

Guiding systems for computer-assisted surgery: introducing synergistic devices and discussing the different approaches

Computer-assisted surgery (CAS) or computer-assisted therapy (CAT) attempt primarily to optimize the performance of medical tasks. CAS systems include a guiding system to connect the information world of data and plans to the physical world of surgeons, patients and instruments, and to supplement the surgeon's perception and dexterity. Passive, semi-active and active systems have been proposed and implemented in various clinical applications. In this paper we introduce synergistic devices which are an extension of semi-active systems. We also discuss the advantages of the different categories of guiding systems on the basis of a list of task-oriented and user-oriented qualitative factors.

Striving for balance: palliative care patients' experiences of making everyday choices

A fundamental principle of palliative care is the provision of patient-centred care, an approach explicitly based on the patient's perspective. Although much attention has been given to determining patients' preferences for involvement in medical decisions, choices related to personal and nursing care routines have been largely ignored in the literature. Data from participant observations of nurse-patient interactions involving 16 palliative care patients and their nurses as well as 10 in-depth open-ended interviews with patients were analyzed using grounded theory methods. Although the choices made by patients appeared uncomplicated on the surface, the context of unfamiliarity, uncertainty, and unpredictability in palliative care increased the underlying complexity of decision making. Through a process of deliberation and trade-offs, patients attempted to regain or maintain some balance in their lives. This process of striving for balance consisted of three overlapping phases: weighing things up, communicating choice, and living with one's choices.

Electron spin resonance spectroscopic detection of oxygen-centred radicals in human serum following exhaustive exercise

Free radicals or oxidants are continuously produced in the body as a consequence of normal energy metabolism. The concentration of free radicals, together with lipid peroxidation, increases in some tissues as a physiological response to exercise - they have also been implicated in a variety of pathologies. The biochemical measurement of free radicals has relied in the main on the indirect assay of oxidative stress by-products. This study presents the first use of electron spin resonance (ESR) spectroscopy in conjunction with the spin-trapping technique, to measure directly the production of radical species in the venous blood of healthy human volunteers pre- and post-exhaustive aerobic exercise. Evidence is also presented of increased lipid peroxidation and total antioxidant capacity post-exercise.

Clinicopathological evidence that neovascularisation is a cause of recurrent varicose veins

OBJECTIVES

Recurrent varicose veins may result from poor initial surgical technique or progression of varicosities in collateral veins. In some cases new veins may develop at the saphenofemoral junction (neovascularisation) and cause recurrent saphenofemoral incompetence. This was a histological study of recurrent varicose veins.

DESIGN

This clinicopathological study included 20 patients (median age 55 years) who had surgery for recurrent saphenofemoral incompetence.

MATERIALS AND METHODS

A total of 28 legs had groin re-exploration with repeat flush saphenofemoral ligation. The venous tissue block from the saphenofemoral region (including the proximal thigh varicosity) was excised and orientated for histological analysis. Evidence of neovascularisation was sought using routine histological sections and S100 immunohistochemistry.

RESULTS

At operation, thin-walled, serpentine neovascular veins were detected clinically as the principal cause of recurrence in 19 groins. In five groins recurrence was due to a residual missed vein at the saphenofemoral junction, and in four recurrence was caused by cross groin collaterals. On histological sections, evidence of neovascularisation was present in 27 of 28 groins. In eight it co-existed with the veins missed at the original operation but it was the sole identified cause of recurrent saphenofemoral incompetence in 19 (68%) groins.

CONCLUSIONS

Neovascularisation was the principal cause of recurrent saphenofemoral incompetence in this series.