The possible role of microchimerism in the aetiology of autoimmune diseases

The aetiology of several autoimmune diseases has not yet been elucidated. Microchimerism, the persistence of small numbers ofallogeneic cells in an individual, has been mentioned recently in connection with the occurrence of autoimmune diseases such as systemic sclerosis and juvenile inflammatory idiopathic myopathy. These allogeneic cells can originate from mutual foeto-maternal exchange of blood cells during pregnancy or from a donor after blood transfusion or (organ) transplantation. In some cases, a syndrome then develops that resembles the chronic graft-versus-host reaction after stem-cell transplantation, in which allogeneic cells react with autologous cells. Studies on microchimerism in patients with systemic sclerosis and juvenile inflammatory idiopathic myopathy, compared to controls, sometimes reveal a clearly increased prevalence of microchimerism in patients. However, microchimerism can also be found in healthy individuals. Direct proof of a causal relation between microchimerism and autoimmune diseases does not exist. Additional genetic or environmental factors may be partly responsible for a disturbed balance between tolerance and aggression.     

Effects of different kinds of fluorides on enolase and ATPase activity of a fluoride-sensitive and fluoride-resistant Streptococcus mutans strain

Enolase and ATPase are sensitive to fluoride. It is unclear whether this sensitivity differs for F-sensitive and F-resistant cells or for different types of fluoride. Permeabilized cells of the fluoride-sensitive strain Streptococcus mutans C180-2 and its fluoride-resistant mutant strain C180-2 FR were preincubated at pH 7 or 4 with NaF, the amine fluorides Olaflur and Dectaflur and amine chloride controls. After preincubations, enolase and ATPase activities of the cells were assessed. Enolase activity was more inhibited after preincubation at pH 7 with NaF than with Olaflur. Amine chloride stimulated, although not with statistical significance, the enolase activity of both strains. After preincubation at pH 4 the enolases were strongly inactivated, but the fluoride-resistant strain's enolase to a lesser extent. The results suggested that amine acts to protect enolase activity against the detrimental low pH effect. Gene sequencing showed that the enolase genes of the fluoride-resistant and fluoride-sensitive strain were identical. ATPase activity was not reduced after NaF preincubation at either pH 7 or pH 4. The amine fluorides and their chloride controls in the preincubation mixture reduced the ATPase activity significantly at both pH values. In conclusion, our results showed that preincubation with amine fluoride did not inhibit enolase activity more effectively than NaF. The amine part of the molecule may protect enolase activity against preincubations at low pH. ATPase activity was not inhibited by NaF preincubation but was significantly inhibited after preincubation with amine fluorides and amine chlorides.     

APF and dentifrice effect on root dentin demineralization and biofilm

Because dentin is more caries-susceptible than enamel, its demineralization may be more influenced by additional fluoride (F). We hypothesized that a combination of professional F, applied as acidulated phosphate F (APF), and use of 1100-ppm-F dentifrice would provide additional protection for dentin compared with 1100-ppm-F alone. Twelve adult volunteers wore palatal appliances containing root dentin slabs, which were subjected, during 4 experimental phases of 7 days each, to biofilm accumulation and sucrose exposure 8x/day. The volunteers were randomly assigned to the following treatments: placebo dentifrice (PD), 1100-ppm-F dentifrice (FD), APF + PD, and APF+FD. APF gel (1.23% F) was applied to the slabs once at the beginning of the experimental phase, and the dentifrices were used 3x/day. APF and FD increased F concentration in biofilm fluid and reduced root dentin demineralization, presenting an additive effect. Analysis of the data suggests that the combination of APF gel application and daily regular use of 1100-ppm-F dentifrice may provide additional protection against root caries compared with the dentifrice alone.     

Value of assessment of tricuspid annulus: real-time three-dimensional echocardiography and magnetic resonance imaging

Aim To detect the accuracy of real-time three-dimensional echocardiography (RT3DE) and two-dimensional echocardiography (2DE) for tricuspid annulus (TA) assessment compared with magnetic resonance imaging (MRI). Methods Thirty patients (mean age 34 ± 13 years, 60% males) in sinus rhythm were examined by MRI, RT3DE, and 2DE for TA assessment. End-diastolic and end-systolic TA diameter (TAD) and TA fractional shortening (TAFS) were measured by RT3DE, 2DE, and MRI. End-diastolic and end-systolic TA area (TAA) and TA fractional area changes (TAFAC) were measured by RT3DE and MRI. End-diastolic and end-systolic right ventricular (RV) volumes and ejection fraction (RV-EF) were measured by MRI. Results The TA was clearly delineated in all patients and visualized as an oval-shaped by RT3DE and MRI. There was a good correlation between TAD_MRI and TAD_3D (r = 0.75, P = 0.001), while TAD_2D was fairly correlated with TAD_3D and TAD_MRI (r = 0.5, P = 0.01 for both). There were no significant differences between RT3DE and MRI in TAD, TAA, TAFS, and TAFAC measurements, while TAD_2D and TAFS_2D were significantly underestimated (P < 0.001). TAFS_2D was not correlated with RV-EF, while TAFS_3D and TAFAC_3D were fairly correlated with RV-EF (r = 0.49, P = 0.01, and r = 0.47, P = 0.02 respectively). Conclusion RT3DE helps in accurate assessment of TA comparable to MRI and may have an important implication in the TV surgical decision-making processes. RT3DE analysis of TA function could be used as a marker of RV function.     

Assessment of tricuspid valve annulus size, shape and function using real-time three-dimensional echocardiography

Tricuspid annulus (TA) evaluation continues to be a major problem in the surgical decision-making process. Obviously, 2-dimensional transthoracic echocardiography (2D TTE) is limited in TA visualization due to its complex 3D shape. The study aimed to determine TA morphology, size and function with real-time three-dimensional echocardiography (RT3DE) in 40 patients divided into two equal groups (I: normal TA and II: dilated). 2D TTE measurements included TA diameter (TAD) at apical 4-chamber (AP4CH) and parasternal short axis (PSAX) views. RT3DE measurements included TA area (TAA), major TAD and minor TAD. TA fractional shortening (TAFS), and TA fractional area change (TAFAC) were calculated from end-systolic and end-diastolic measurements. RT3DE allowed visualization and measurement of the entire oval-shaped TA in all patients irrespective of its size (normal or dilated). 2D TTE measurement of TAD at both AP4CH and at PSAX views was significantly smaller than the major TAD measured by RT3DE (P<0.0001) and nearly matched with the minor TAD in all patients. Calculation of TAFS was comparable with both techniques. TAFAC was significantly higher than TAFS (P<0.0001). So, RT3DE could be relied on more accurately than 2D TTE in the assessment of TA size and function which may aid in decision-making and selection of proper surgical procedure when indicated.     

Potential Additional Indicators for Pacemaker Requirement in Isolated Congenital Atrioventricular Block

Low heart rate is the predominantly used indication for pacemaker intervention in patients with isolated congenital atrioventricular block (CAVB). The aim of this study was to compare the difference in heart rates recorded with ECG and Holter monitoring between paced (PM) and nonpaced (NPM) patients with isolated CAVB before pacemaker implantation to identify additional predictors for future PM need. Retrospective evaluation of atrial and ventricular rates (electrocardiography) and minimal and maximal (Holter) heart rates in 129 CAVB patients prior to PM implantation (n = 93) was performed, and results are expressed in V adjusted for age and sex. The average V score for the atrial rate was 0.51 (n = 50) in the PM group and 0.60 (n = 22) in the NPM group (not-significant). The average z score for the ventricular (average) rate was −0.91 (n = 83) in the PM group and −0.93 (n = 33) in the NPM group (not-significant). Minimal heart rate was −0.94 (n = 61) in the PM group and −0.86 (n = 25) in the NPM group (not significant). Maximal heart rate was −0.96 (n = 61) in the PM group and −0.95 (n = 26) in the NPM group (not significant). Initial recordings of the average heart rate and the minimal and maximal heart rate recorded during Holter monitoring do not seem to predict future pacemaker need in patients with CAVB. Studies with exercise stress tests are needed to confirm these findings.     

Antiplatelet therapy and other interventions after revascularisation procedures in patients with peripheral arterial disease: a meta-analysis.

OBJECTIVES: To evaluate the efficacy of conservative adjuvant therapy after revascularisation procedures in patients with peripheral arterial disease. DESIGN: meta-analysis. MATERIALS: English-language studies published from 1976 to 1997. METHODS: Reports on conservative therapies in patients with peripheral arterial disease after percutaneous transluminal angioplasty, endarterectomy, thromboendarterectomy or bypass grafting were eligible. Uncontrolled or retrospective studies, double reports or trials without clinical outcomes were excluded. Included studies were graded as level 1 (randomised and double- or assessor-blind), level 2 (open randomised), or level 3 (non-randomised comparative). (Loss of) patency, amputation, vascular events and mortality were the outcomes considered. When feasible, end-of-treatment results, either continuous or binary, were combined with appropriate statistical methods. RESULTS: Thirty-two studies were included. Compared to non-active control, aspirin with dipyridamole improved (loss of) patency (odds ratio (OR) 0.69, 95% confidence interval (CI), 0.53 to 0.90) and mortality (OR 0.80, 95% CI, 0.57 to 1.14); ticlopidine improved (loss of) patency (OR 0.53, 95% CI, 0.33 to 0.85) and amputation (OR 0.29, 95% CI, 0.08 to 1.01). Data on the effectiveness of vitamin-K inhibitors were not conclusive. CONCLUSIONS: Patients with peripheral arterial disease improve their outcome by receiving aspirin with dipyridamole or ticlopidine after a revascularisation procedure.