[Principles of oral health care for children]. / Uitgangspunten van mondzorg voor kinderen.

In this article the principles of child oral health care in the Netherlands and the consequences of cariological principals of oral health care delivery to children are described. First of all the age of the child plays a very significant role in decisions concerning prevention and restoration. In addition, the combination of a positive attitude on the part of the dentist and a pain-free treatment can prevent fear of treatment and avoidance behaviour of the children. In the treatment of carious lesions, moreover, the oral health care provider should consider to what extent the problem is related to behaviour and fits in the multi-factorial caries model. Restorative treatments should be considered as supporting prevention, reducing caries activity and eliminating the effects of neglected oral health care. Prevention has to be seen as an essential element of the treatment model and it should start early from the standpoint of habit formation and the rapid demineralization process in the deciduous dentition which results from failed preventive care.

[Post-academic dental specialties. 10. Post-academic specialization in pediatric dentistry]. / Beroepsdifferentiatie in de tandheelkunde 10. De differentiatieopleiding tot tandarts-pedodontoloog.

As is the case with other dental disciplines, pediatric dentistry has moved in the direction of a specialized educational programme. After a cautious start at the end of the last century, the European Academy of Paediatric Dentistry (EAPD) and the Dutch Association of Pediatric Dentistry have now recognized the previously existing programme at the Academic Center for Dentistry Amsterdam (ACTA) and a register for dentists-pedodontologists has been established. Recently, about 30 dentist-pedodontologists have received their certification. They work in private practice, pedodontic secondary dental practice and centers for special dental care as well as in university (hospital) clinics. They willingly assist the general dental practitioner with advice and active treatments.

Hyperglycemia-induced thrombin formation in diabetes. The possible role of oxidative stress.

Diabetes is characterized by the existence of a thrombosis-prone condition, possibly related to hyperglycemia. However, the mechanism linking hyperglycemia to the activation of the coagulation cascade is still unclear. It has been recently suggested that diabetes is accompanied by increased oxidative stress. In this work, the possibility that oxidative stress may be involved in the hyperglycemia-induced coagulation activation has been evaluated. Prothrombin fragment 1 + 2 (F1 + 2), which represents a reliable marker of the amount of thrombin released in the circulation, has been chosen for studying thrombin formation in vivo. In nine type II diabetic patients and in seven healthy control subjects, matched for age and body mass index, three different experiments were performed: oral glucose tolerance test (OGTT), intravenous antioxidant glutathione (GSH) administration for 2 h, and OGTT plus intravenous GSH administration. Samples were drawn at -15 min and every 30 min from 0 to 180 min. During the OGTT, F1 + 2 significantly increased in both diabetic and healthy subjects. GSH administration during OGTT normalized this phenomenon. GSH administration alone significantly decreased F1 + 2 in diabetic patients, while no effect was observed in the normal subjects. These data suggest that hyperglycemia may induce thrombin activation, possibly inducing an oxidative stress, and that antioxidant GSH may counterbalance this effect.

Total plasma antioxidant capacity predicts thrombosis-prone status in NIDDM patients.

OBJECTIVE: To explore the hypothesis that a relationship exists between free radical activity and abnormalities in hemostasis in NIDDM. RESEARCH DESIGN AND METHODS: The use of the total radical-trapping antioxidant parameter (TRAP) has very recently been proposed to explore the antioxidant property of a plasma and their mutual cooperation. In the present study, TRAP, vitamin E, vitamin C, vitamin A, uric acid, protein-bound SH (thiol) groups, fibrinogen, prothrombin fragments F1 + 2, and D-dimer have been evaluated in 46 NIDDM patients and 47 healthy matched control subjects. RESULTS: In NIDDM patients, TRAP, vitamin A, SH groups, and uric acid were significantly reduced, whereas the level of vitamin E was significantly increased. Vitamin C was similar in the two groups. Fibrinogen, prothrombin fragment 1 + 2, and D-dimer were increased in diabetic patients. TRAP, but no single other antioxidant, had a strong inverse association with fibrinogen, prothrombin fragment 1 + 2, and D-dimer. CONCLUSIONS: These findings are consistent with the hypothesis that oxidative stress may condition coagulation activation in diabetics. However, the data suggest that it is the total antioxidant capacity rather than any single plasma antioxidant that is the most relevant parameter.

A new model of human aortic endothelial cells in vitro.

Vascular endothelial cells play an important role in coagulation regulation of vascular tone and in a variety of synthetic and metabolic functions. Endothelial cells also have a pivotal role in immunological diseases atherogenesis and tumor angiogenesis. Endothelial cells are often used as system to study the pathophysiology of late complications in diabetes mellitus atherosclerotic damages and leukocyte adhesion in inflammatory diseases. Most of the studies have been performed on primary arterial and venous endothelial cell cultures with problems such as availability of autoptic material and reproducibility of cell cultures. We have isolated and characterized a novel system of proliferating long-term cultures of human aortic endothelial cells that maintain their differentiated characteristics for many generations in vitro. They produce antithrombotic and thrombotic factors such as t-PA and PAI-1 and respond to TNFalpha, an important factor correlated with the inflammatory process by modifying growth characteristics by producing cytokines such as GM-CSF by expressing ICAM-1 on the surface and by producing large amounts of nitric oxide and endothelin. This new system may be very useful to understand and study the molecular mechanisms involved in many vascular alteration pathologies and in the aging process.

Fibrinogen plasma levels as a marker of thrombin activation: new insights on the role of fibrinogen as a cardiovascular risk factor.

Fibrinogen has recently emerged as a major risk factor for atherothrombosis. However, the pathophysiologic mechanism linking high fibrinogen concentration to cardiovascular disease is unclear. In this study 136 subjects (75 males, 61 females, age 51.7 +/- 14.4 years, mean +/- standard deviation, range 17-82) were tested for total and HDL-cholesterol, total triglycerides, apolipoprotein AI, apolipoprotein B, fibrinogen, prothrombin fragment and D-dimer. Moreover, 5 subjects who had hyperfibrinogenemia (range 450 to 950 mg/dl) for at least 6 months by repeated measurements, were treated with a short 7-day course of heparin 12,500 U/day subcutaneously. The effect of heparin on all the above mentioned parameters was observed at the end of treatment and after 7 days of wash-out. Simple regression analysis detected a positive correlation between fibrinogen and age, prothrombin fragment and D-dimer, and a negative correlation between fibrinogen and HDL-cholesterol and apolipoprotein AI. A direct correlation between age and both prothrombin fragment and D-dimer was also demonstrated. Multivariate analysis showed a persistent correlation between fibrinogen and prothrombin fragment, D-dimer and age, that was not influenced by sex, smoking habit and body mass index. In the 5 hyperfibrinogenemic subjects, heparin administration significantly reduced fibrinogen (625.4 +/- 211.1 vs 455.2 +/- 112.3 mg/dl, p < 0.03), prothrombin fragment (0.97 +/- 0.1 vs 0.63 +/- 0.2 nM, p < 0.002) and D-dimer (336 +/- 101.8 vs 275.2 +/- 78.5 ng/ml, p < 0.03). All these parameters returned to baseline after 7 days of wash-out (fibrinogen 632.5 +/- 198.2 mg/dl, prothrombin fragment 0.96 +/- 0.2 nM, D-dimer 325.8 +/- 98.65 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

The defence against free radicals protects endothelial cells from hyperglycaemia-induced plasminogen activator inhibitor 1 over-production.

It has been shown that hyperglycaemia may stimulate plasminogen activator inhibitor 1 (PAI-1) over-production in human endothelial cells in culture. At the same time, it has been shown that glucose may enolize, producing free radicals. In this study, the possibility that hyperglycaemia stimulates PAI-1 over-production in human endothelial cells in culture by generating free radicals has been evaluated. For this purpose two experimental models were used: human endothelial cells transfected to express high glutathione peroxidase levels cultured in hyperglycaemic media, and human endothelial cells cultured in hyperglycaemic media with the antioxidant GSH. Cells grown in 20 mM glucose produced higher values of PAI-1 with respect to controls. The production of PAI-1 was not influenced by hyperglycaemia in transfected cells. GSH in the medium reduced hyperglycaemia-induced PAI-1 over-production, but also reduces the basal production of PAI-1 in the cells grown in normal glucose concentration. These data show that antioxidant defences may reduce hyperglycaemia-induced PAI-1 over-production in human endothelial cells in culture. The hypothesis that oxidative stress may play an important role in the pathogenesis of diabetic complications is then supported by this study.

[Dental care for the handicapped patient]. / Tandheelkundige zorg voor kwetsbare groepen.

In the last years the caries risk in the Netherlands has shifted to vulnerable groups consisting of people unable to commit themselves to independent preventive dental care. These groups, children with behaviour management problems, mentally disabled, and elderly people make a change in the perspective of preventive dental care necessary. A more individual approach is advised. The costs of the changes possibly have to be drawn from the regular dental budget.

Accuracy of a portable glucose meter and of a Continuous Glucose Monitoring device used at home by patients with type 1 diabetes.

BACKGROUND: Patients with diabetes are recommended to self-monitor their blood glucose levels also at home. Accuracy of a hand-held glucometer and a Continuous Glucose Monitoring (CGM) device were comparatively evaluated. METHODS: Venous blood samples (for reference laboratory determinations; n=428) were collected from 18 type 1 patients (35-65 years old), immediately followed by capillary measurement (Bayer ContourLink meter) and CGM readings (Medtronic Paradigm). RESULTS: Laboratory values did not differ statistically from ContourLink and CGM readings, mean difference (±SD) being -0.05±1.06 mmol/L and 0.10±1.84 mmol/L glucose, respectively. A bias ((value-reference)/reference×100) ≥15% was observed in 27.7% and 54.9% of cases, respectively. Notably, below 3.9 mmol/L glucose (hypoglycemic threshold), an absolute error>0.8 mmol/L was found in 78.9% and 94.1% of cases. The absolute errors of the CGM device were inversely related to the rate of glucose change (r=0.598, p<0.001). CONCLUSIONS: A very large error was observed at the extreme glycemic values, which may lead to erroneous therapy. Consequently, performance of future portable glucometers should be focused in particular under hypo- and hyper-glycemia. Moreover, integrated CGM devices should not disregard the effect of the rate of blood glucose change on the sensor readings.

Effect of intensive glycaemic control on fibrinogen plasma concentrations in patients with Type II diabetes mellitus. Relation with beta-fibrinogen genotype.

Recent studies show that in diabetic subjects an increase of plasma fibrinogen concentration is associated with a high risk of cardiovascular complications. Environmental and genetic factors contribute to the plasma fibrinogen concentration. Several studies indicate a relation between the polymorphism in the 5' region of the beta-fibrinogen gene and plasma protein concentrations and in diabetes the possible influence of hyperglycaemia on fibrinogen is still debated. In this study we investigated these relations. Hind III polymorphism was evaluated by a polymerase chain reaction-technique. On the basis of the observed allelic combination of fibrinogen beta-gene polymorphism and the existence of poor metabolic control (glycated haemoglobin > or = 7.5%), 50 Type II diabetic patients were selected. They were divided into three groups according to their beta-gene polymorphism (alpha1alpha1: n = 20, alpha1alpha2: n = 15, alpha2alpha2: n = 15) and then intensive insulin therapy was started. After 3 months of intensive treatment, the improvement in glycaemic control was equivalent, in terms of glycated haemoglobin, in all the three groups. A fibrinogen reduction was observed in alpha1alpha2 and alpha2alpha2 but not in alpha1alpha1 subjects. These results underline a possible relation between fibrinogen genotypes and glycaemic control in determining plasma fibrinogen concentrations in diabetic patients.

Long-term effects of erythropoietin therapy on fistula stenosis and plasma concentrations of PDGF and MCP-1 in hemodialysis patients.

Among the adverse effects possibly associated with the use of erythropoietin (EPO) in hemodialysis patients is an increased incidence of thrombosis of the vascular access. However, little is known about the effect of EPO on the stenotic lesion in the venous outflow system, which is the leading cause of fistula thrombosis. This study was designed to explore the long-term effects of EPO treatment on progressive fistula stenosis and the plasma concentrations of some potential mediators of neointimal hyperplasia. A cross-sectional and 3-yr prospective, placebo-controlled, pilot study was performed in 30 hemodialysis patients with native arteriovenous fistula. Sixteen patients received EPO and 14 received a placebo. Venous dialysis pressure, urea recirculation, color Doppler sonography, and angiography were used to monitor vascular access patency. Compared with 60 healthy subjects, the hemodialysis patients had elevated plasma levels of platelet-derived growth factor, monocyte chemoattractant protein-1, and interleukin 6, three proteins that might be involved in the neointima formation regulating the proliferation of vascular smooth muscle cells. In addition, these patients had numerous endothelial and hemostatic abnormalities that indicated a thrombophilic state. Eleven patients, six (37.5%) receiving EPO and five (35.7%) taking placebo, developed a progressive stenosis in the venous circuit of the fistula. There was no significant difference in the vascular access, event-free survival over 36 mo between patients receiving EPO therapy and placebo. EPO induced a significant decrease in the plasma values of platelet-derived growth factor and vascular cell adhesion molecule-1 and an increase of monocyte chemoattractant protein-1 concentration. After EPO withdrawal, these parameters returned to pretreatment levels. In conclusion, long-term EPO therapy does not increase the risk of progressive stenosis of native arteriovenous fistula. The use of erythropoietin does not induce any prothrombotic change in hemostatic parameters, and further studies are required to elucidate the theoretically beneficial effects on the plasma concentration of some potential mediators of neointimal formation.

Risk factors for vascular disease and arteriovenous fistula dysfunction in hemodialysis patients.

Vascular access dysfunction is an important cause of morbidity for dialysis patients and a major contributor to hemodialysis cost. Thrombosis is a leading cause of vascular access failure, and usually results from stenotic lesions in the venous outflow system. This study was designed to explore the impact of serum levels of various risk factors for thrombosis and accelerated fibrointimal hyperplasia on progressive stenosis, and the subsequent thrombosis of hemodialysis fistula. A cross-sectional and 2-yr prospective pilot study was performed in 30 nondiabetic hemodialysis patients with primary arteriovenous fistula. Venous dialysis pressure, urea recirculation, color Doppler sonography, and angiography were used to monitor vascular access patency. Eleven patients (37%) developed a progressive stenosis in the venous circuit, which was complicated by thrombosis in three patients. Compared with the patients without fistula dysfunction, these patients had higher serum levels of monocyte chemoattractant protein-1 and interleukin-6, two cytokines that regulate the proliferation of vascular smooth muscle cells, which is the key mechanism in the pathogenesis of fistula stenosis. In addition, they had hyperinsulinemia, hyperlipidemia, and increased plasma levels of two hemostasis-derived risk factors for thrombosis: plasminogen activator inhibitor type 1 and factor VII. Monocyte chemoattractant protein-1, interleukin-6, plasminogen activator inhibitor type 1, factor VII, triglycerides, and the ratios for cholesterol/HDL-cholesterol, apolipoprotein (apo) A-I/ apo C-III, apo A-I/apo B, and glucose/insulin were independent predictors of fistula dysfunction. This study demonstrates the influece of cytokines, hemostasis-derived vascular risk factor, hyperinsullnemia, and abnormallties of lipids and apolipoproteins on primary fistula survival. The assessment of these factors might be useful for the identification of the patients at risk of fistula stenosis and thrombosis.