Optical coherence tomography-based assessment of retinal vascular pathology in cerebral small vessel disease

Background

Cerebral small vessel disease (CSVD) is a disorder of brain vasculature that causes various structural changes in the brain parenchyma, and is associated with various clinical symptoms such as cognitive impairment and gait disorders. Structural changes of brain arterioles cannot be visualized with routine imaging techniques in vivo. However, optical coherence tomography (OCT) is thought to be a “window to the brain”. Thus, retinal vessel parameters may correlate with CSVD characteristic brain lesions and cerebrospinal fluid biomarkers (CSF) of the neuropathological processes in CSVD like endothelial damage, microglial activation and neuroaxonal damage.

Methods

We applied OCT-based assessment of retinal vessels, magnetic resonance imaging (MRI), and CSF biomarker analysis in a monocentric prospective cohort of 24 patients with sporadic CSVD related stroke and cognitive impairment. MRI lesions were defined according to the STandards for ReportIng Vascular changes on nEuroimaging (STRIVE). Biomarkers were assessed using commercially available ELISA kits. Owing to the unavailability of an age-matched control-group lacking MRI-characteristics of CSVD, we compared the retinal vessel parameters in CSVD patients (73.8 ± 8.5 years) with a younger group of healthy controls (51.0 ± 16.0 years) by using an age- and sex-adjusted multiple linear regression analysis model.

Results

Among the parameters measured with OCT, the Wall to Lumen Ratio (WLR) but not Mean Wall Thickness (MWT) of the superior branch of the retinal artery correlated significantly with the volume of white matter hyperintensities on MRI (r_s = − 0.5) and with CSF-levels of Chitinase 3 like 1 protein (r_s = − 0.6), zona occludens 1 protein (r_s = − 0.5) and GFAP (r_s = − 0.4). MWT and WLR were higher in CSVD than in controls (28.9 μm vs. 23.9 μm, p = 0.001 and 0.32 vs. 0.25, p = 0.001).

Conclusions

In this exploratory study, WLR correlated with the volume of white matter hyperintensities, and markers of vascular integrity, microglial activation, and neuroaxonal damage in CSVD. Further prospective studies should clarify whether retinal vessel parameters and CSF biomarkers may serve to monitor the natural course and treatment effects in clinical studies on CSVD.

Strahlenresistenz, Gehalt und Basenzusammensetzung der DNA einiger strahleninduzierter Mutanten von Azotobacter chroococcum

An zwei Azotobacter chroococcum-Stämmen und 14 von diesen abgeleiteten unterschiedlich strahlenresistenten Mutanten wurde geprüft, ob zwischen der Resistenz gegen Röntgenstrahlen und dem DNA-Gehalt pro Zelle einerseits und dem Guanin-Cytosin-Anteil der DNA andererseits direkte Beziehungen bestehen. Nach den vorliegenden Ergebnissen steht die Strahlensensibilität der unterschiedlich strahlenresistenten Mutanten zweier Bakterienstämme, deren GC-Gehalt zwischen 59 und 66% variiert, unter einheitlichen Bestrahlungsbedingungen in linearer Beziehung sowohl zum DNA-Gehalt als auch zum prozentualen Anteil der GC-Basenpaare.

Magnetocardiographic mapping of QRS fragmentation in patients with a history of malignant tachyarrhythmias

BACKGROUND

The identification of patients at increased risk for ventricular tachycardia or ventricular fibrillation (VT/VF) and sudden cardiac death has consequences for therapeutic options and thus may reduce mortality in patients with coronary artery disease (CAD).

HYPOTHESIS

We hypothesized that the intra-QRS fragmentation in magnetocardiographic recordings is increased in patients with CAD and with a history of VT/VF.

METHODS

Multichannel magnetocardiography (MCG) was carried out in 34 healthy controls, 42 patients with CAD without a history of VT/VF, and 43 patients with CAD and with a history of VT/VF. The intra-QRS fragmentation was quantified by a new fragmentation score. Its spatial distribution was investigated using two-dimensional (2-D) contour maps according to the sensor position of the 49-channel magnetogradiometer.

RESULTS

Patients with CAD and with a history of VT/VF had significantly increased QRS fragmentation compared with patients with CAD without VT/VF or controls (72.9+/-37.5, 48.5+/-14.3, and 42.5+/-7.8, respectively: p <0.05). The area of high fragmentation in 2-D contour maps was twice as large in patients with than in those without a history of VT/VF (represented by the number of MCG channels with high fragmentation: 26.3+/-15.5 vs. 12.4+/-9.9, p<0.0001). Patients prone to VT/VF could be identified with a sensitivity of 64% and a specificity of 90%.

CONCLUSION

In patients with CAD and with a history of VT/VF, intra-QRS fragmentation is increased and the area of high fragmentation in 2-D contour maps is enlarged. These findings may be helpful in identifying patients with CAD at risk for malignant tachyarrhythmias.

A combination of alleles 2 of interleukin (IL)-1A(-889) and IL-1B(+3954) is associated with lower gingival bleeding tendency in plaque-induced gingivitis in young adults of Arabic heritage

The aim of this study was to investigate the possible association of a distinct combination of polymorphisms in the interleukin (IL)-1 gene cluster on gingival bleeding tendency in young adult Arabs with plaque-induced gingivitis. Fifty otherwise healthy, nonsmoking volunteers, 19-28 years of age, participated. Clinical examinations included periodontal probing depth, bleeding on probing, and plaque index. Probing was done with a pressure-controlled probe at about 1.27 MPa. Examinations were repeated after 2 and 4 weeks. Polymorphisms in the IL-1 gene cluster were assessed using a reverse hybridization assay. A subject carrying alleles 2 at IL-1A ( -889 ) and IL-1B ( +3954 ) was designated genotype-positive. Twenty-six subjects were genotype-positive (52%). A repeated measures two-level (occasion, subject) model of the proportion of sites bleeding on probing, which was adjusted for gender, average plaque index, probing depth, and calculus, revealed a significantly lower proportion of bleeding sites in genotype-positive subjects (estimate -0.050, standard error 0.025, p < 0.05). Biserial correlations of bleeding proportions were high (0.71-0.78), confirming the steady-state plaque environment. It was concluded that inflammatory responses to dental plaque were considerably dampened in genotype-positive, nonsmoking young adults of Arabic heritage.

Effect of triclosan/copolymer-containing toothpaste on the association between plaque and gingival bleeding: a randomized controlled clinical trial

AIM

To study longitudinal associations between plaque and gingival bleeding and multilevel variance/covariance structures after introducing triclosan-containing toothpaste.

MATERIAL AND METHODS

A 10-week, randomized, two-arm, double-masked, controlled clinical trial was conducted in 34 healthy, non-smoking females with plaque-induced gingivitis. Clinical periodontal examinations were repeated every other week. At week 4, test toothpaste containing 0.24% sodium monofluorophosphate, 0.3% triclosan, and 2% polyvinyl-methyl ether maleic acid; or control toothpaste containing 0.76% sodium monofluorophosphate and 0.1% sodium fluoride, were randomly distributed.

RESULTS

Multivariate multilevel models indicated that, after introducing experimental toothpastes, subject random error was reduced from 0.6 to below 0.2. The odds ratio (OR) of bleeding on probing (BOP) was about 30% less in the test than in the control group (p<0.01). At the end of the experiment, ORs for BOP and plaque index scores 1-3 (reference 0) were 2.1-2.4 in the control group, but 1.1-1.9 in the test group (p<0.05). No effects on plaque levels and calculus were observed.

CONCLUSIONS

Multivariate multilevel modelling allows the study of fixed and random effects of experimental toothpastes on gingival inflammation in small sample. Triclosan appears to attenuate the causal association between supragingival plaque and gingival bleeding in gingivitis.

Multivariate multilevel models for repeated measures in the study of smoking effects on the association between plaque and gingival bleeding

Multivariate multilevel modeling was applied to analyze repeated measures data on the influence of heavy smoking on the association between the amount of supragingival plaque and gingival bleeding on probing (BOP) in a steady-state plaque environment. Data acquired in 65 systemically healthy young adults with mild plaque-induced gingivitis were analyzed. 33 heavy smokers consumed at least 20 cigarettes per day while 32 were non-smokers. Periodontal examinations at the outset consisted of periodontal probing depth, clinical attachment level, BOP, plaque index, and presence of calculus at 6 sites of every tooth present. They were repeated 3 times every 8 weeks. A multivariate 4-level variance component model revealed that the odds of BOP was twice as high in smokers. In addition, females had a lower likelihood for BOP but, with increasing bleeding scores during the course of the study, this effect attenuated. Low biserial correlations for BOP at the site level of between 0.11 and 0.2 were found. At the tooth level, correlations were moderate (0.2-0.5), and highest at the subject level (0.8-0.9). Variations at subject and tooth levels were very large at the outset but notably attenuated in the course of the study. Plaque consistently influenced the tendency for BOP with an odds ratio of about 1.7-1.8 for each increase in score in both smokers and non-smokers. The present study did not reveal evidence for attenuation of the plaque/gingival bleeding relationship in heavy smokers.

Gingival bleeding on repeat probing after different time intervals in plaque-induced gingivitis

The aim of this study was to assess agreement and association of gingival bleeding after repeated probing at different time intervals in subjects with gingivitis. Twenty adults participated. Periodontal probing (P approximately 1.27 MPa) was conducted at six sites of every tooth present. Probing was repeated in different quadrants immediately after the first probing (T0), after 1 h (T1), 4 h (T4), and 24 h (T24). A total of 3,459 sites were probed twice. The mean proportion of sites bleeding on probing (BOP) was 0.23 (standard deviation 0.08, range 0.10-0.41). Probing itself had a significant effect on the results of repeated probing. For T0 through T24, respective mean differences of proportions were 0.04, 0.04, 0.01, and -0.03. Ninety-five percent repeatability coefficients of proportions were 0.17-0.18. Estimates of overall kappa were 0.390, 0.234, 0.233, and 0.046 for T0 through T4, respectively. Adjusted two-level binary response models revealed odds ratios (95% confidence interval) for BOP at T0 through T4 of 6.52 (4.34, 9.80), 3.23 (2.19, 4.76), 3.80 (2.63, 5.50), and 2.68 (1.85, 3.89). It was concluded that a certain degree of agreement of site-specific bleeding scores in subjects with plaque-induced gingivitis could be observed only if probing was repeated at once. Adjusted associations between repeat BOP were weak in general, but strongest immediately after first probing. There appears to be a significant effect of probing itself, which may last for more than 1 h, whereas 24-h results are obtained under different conditions.

Open magnetic and electric graphic analysis

The OMEGA software provides an analysis platform for user-independent, fast, and reproducible multimodal data analysis in one single software environment. Synergetic interactions pursued between the two functional imaging techniques fMRI and MEG use the morphological MRI recording as a basis for a common coordinate frame. In this way, direct interchange, comparison, and integration among the results of the different modalities have become feasible. The fMRI data analysis provides information about the localization of functional activity with low temporal resolution, whereas the MEG recording complements the corresponding time evolution with a high temporal resolution. The implementation of OMEGA allows the analyst to receive comprehensive MEG/fMRI results in a matter of minutes after the measurements have been completed. With OMEGA, the clinical researcher gets comprehensive information in a quick and standardized approach about the sites and the time course of neurological activation, which is useful for clinical applications and diagnostics.

Variance components of gingival thickness

OBJECTIVES

Distinct periodontal phenotypes have been identified by cluster analysis, which is an explorative method with very low external validity. The aim of the present study was to investigate variance components of facial gingival thickness in young adults with mild gingivitis.

MATERIAL AND METHODS

Thirty-three non-smoking females, 18-23 years of age, with mild or moderate plaque-induced gingivitis participated. Gingival thickness was measured at every tooth present by use of ultrasound technology to the next 0.1 mm with a lowest measurement of 0.5 mm. Periodontal probing depth and clinical attachment level were measured with a pressure-controlled probe. Gingival bleeding index was assessed after probing on a 0-2 scale, where 1 was slight, and 2 was profuse bleeding on probing. The Silness-Loe plaque index was recorded. Multilevel variance components and random intercept models were built.

RESULTS

A 2-level (subject, tooth) variance component model of gingival thickness without any explanatory variable revealed an intercept (mean) of 0.93 +/- 0.02 mm. Subject variation of gingival thickness amounted to 4.2% of the total variance. Addition of tooth- and subject-related covariates to the model revealed, after adjusting for tooth type, an association with periodontal probing depth (estimated coefficient 0.067 +/- 0.025), and considerable association with average bleeding index (-0.395 +/- 0.149) and plaque index (0.125 +/- 0.048). Variation at the tooth level was drastically reduced; subject variation amounted to 5.2%.

CONCLUSION

Gingival thickness is mainly associated with tooth-related variables. Bleeding tendency is higher if gingiva is thin. Subject variability related to periodontal phenotype may add to the total variance, however, to a very low extent.

The influence of gingival dimensions on bleeding upon probing in young adults with plaque-induced gingivitis

In both cross-sectional and longitudinal studies of young adults with plaque-induced gingivitis it has been observed that bleeding upon probing is only weakly associated with supragingival plaque. It has been speculated that gingival bleeding may be influenced by several independent factors other than plaque. Great intra- and interindividual variation of gingival thickness and width has been reported. Based on respective observations, the existence of different gingival phenotypes has been suggested. The aim of the present study was to investigate the possible influence of gingival thickness and width on bleeding on probing. Forty young adults with mild, plaque-induced gingivitis, 24 non-smokers and 16 smokers, participated in this cross-sectional study. In addition to periodontal probing depth, clinical attachment loss, width of gingiva, bleeding on probing, and presence of plaque, gingival thickness was measured with an ultrasonic device. Multivariable models were separately calculated for buccal, mandibular lingual, and palatal surfaces and generally adjusted for tooth type. Generalised Estimation Equation methodology was employed in order to adjust for correlated observations. Plaque was significantly associated with bleeding upon probing only at buccal sites (odds ratio 1.80, 95% confidence interval 1.19-2.72) An influence of similar magnitude was identified for smoking (odds ratio 1.76; 1.07-2.89). At lingual sites in the mandible, bleeding was influenced by smoking (odds ratio 2.25; 1.18-4.25) and gingival thickness (odds ratio for thick gingiva >1 mm of 1.93; 1.02-3.65), but not plaque. At palatal sites, only periodontal probing depth had an influence (odds ratio 1.89; 1.25-2.84). It was concluded that, apart from supragingival plaque, smoking was an independent risk factor for gingival bleeding on probing. Thin and vulnerable gingiva of insufficient width was not more likely to bleed after probing than thicker tissue.

[Does chronic periodontitis play a role in the pathogenesis of cardiovascular and cerebrovascular diseases?]

The role of chronic infections in the initiation of atherosclerotic lesions has been vividly discussed in recent years. A possible causal relationship between cardiovascular diseases and infections with, e. g., Chlamydia pneumoniae, Helicobacter pylori, or herpes viruses had also been established for chronic periodontitis, in particular after discovery of DNA of typical periodontal pathogens in atheromatous plaques. Especially in longitudinal epidemiologic studies, a low or moderate association between existing periodontitis and the development of, e. g., coronary heart disease or non-haemorrhagic stroke had been observed. In this article the respective literature is critically reviewed. In particular, the influence of incomplete or inappropriate adjustment for common risk factors for both diseases, i. e., cardiovascular disease and periodontitis should be analysed. In metaanalyses of prospective studies, in which the respective endpoint occurred after the investigation had commenced, relative risks of periodontitis of 1.12 (95 % confidence interval 0.95-1.33) for coronary heart disease and 1.73 (0.89-3.34) for ischaemic stroke were calculated. Whether chronic periodontitis actually represents an important risk for the development of cardiovascular diseases remains questionable. Already planned intervention studies appear to be premature and ethically highly problematic.

[Quality management: internal guidelines and critical pathways for patients]

BACKGROUND

The construction and implementation of "Practice Guidelines" was one of the most important developments in American medicine of the last 15 years. There is ongoing controversy about the effectiveness of these guidelines to get introduced into practice. It has been proved, however, that guidelines developed by care organizations themselves, will show a higher effectiveness and acceptance and will achieve more positive results (Internal Guidelines, "Locally Owned" Standards). "Mipp": Internal Guidelines are also the starting point for the patient pathways of the model of integrated patient pathways "mipp", developed at the Kantonsspital Aarau in the last 7 years. The model is presented with its main features: Construction and Implementation of Pathways, Path-Controlling, Path-Benchmarking and Path-Visualization. "Mipp" Pathways share with Clinical Pathways the interdisciplinary perspectives for an efficient quality management. The description of processes is combined with an integrated calculation of costs, which is the basis of standard cost accounting and even activity based-costing.

CONCLUSION

In the field of upcoming prospective payment systems (PPS) like ARDRG, APDRG etc. it is of utmost importance for care organizations to have a clear view regarding the treatment processes and the possibilities of their improvement.

Bleeding on probing in smokers and non-smokers in a steady state plaque environment

An altered gingival inflammatory response to supragingival plaque in smokers had been claimed by several authors. Relatively limited information exists with regard to the consistency of naturally occurring plaque and bleeding upon probing within the oral cavity under usual oral hygiene measures. The aims of the present study were to describe the distribution of tooth surfaces covered by supragingival plaque and gingival units bleeding upon probing in a steady state environment of no dental intervention. In addition relative consistency of plaque and bleeding was investigated. 65 volunteers, 14 women and 51 men in the age range of 19 to 30 years, participated. 33 volunteers were heavy smokers and 32 non-smokers. Clinical examinations revealed mild, plaque-induced gingivitis with no overt destructive periodontitis. Within a 6-month period. presence and amount of plaque, calculus and gingival bleeding was site-specifically assessed four times, i.e., every 8 weeks. Well-defined, symmetric and consistent patterns of plaque and calculus distribution within the oral cavity were observed, which were rather identical in smokers and non-smokers. Smokers had evenly more plaque in all regions of the oral cavity. In contrast, there was no obvious pattern of bleeding upon probing. Consistency of observations was considerably lower than for plaque scores. This was particularly true for smokers, where the association between bleeding scores was generally smaller than in non-smokers. A large portion of the variation of gingival bleeding may be due to presently unknown factors other than plaque and calculus with considerable consequences for preventive programmes.

Gingivitis in young adults with Actinobacillus actinomycetemcomitans

High intraoral load of A. actinomycetemcomitans in subjects with no or minimal periodontal disease may induce subtle changes in clinical periodontal conditions. The aim of the present study was to compare, at a site level, clinical conditions in two groups of young adults with plaque-induced gingivitis. In one group, more than 20% subgingival sites harboured cultivable A. actinomycetemcomitans (n=9), whereas in the other group, the organism was present in 20% or fewer subgingival plaque samples (n=8). Whereas no overt differences in clinical conditions could be ascertained, on average, the association between the presence of subgingival plaque and bleeding upon probing was considerably stronger (Mantel-Haenszel's common odds ratio RMH and 95% confidence interval 3.903, 2.951-5.165, P<0.001) in subjects with only a few subgingival sites harbouring A. actinomycetemcomitans as compared to subjects with a widespread intraoral distribution of the organism (R(MH)=1.637, 1.226-2.184, P<0.001). Since the proportion of sites not bleeding upon probing in the presence of supragingival plaque was slightly elevated in these subjects, the present findings may suggest a suppressed inflammatory reaction on supragingival plaque in the presence of a pronounced intraoral load of A. actinomycetemcomitans.

Failure of root coverage of shallow gingival recessions employing GTR and a bioresorbable membrane

The aim of the present study was to compare the postsurgical outcome of two different modes of surgical root coverage of predominantly shallow, Class I or II, gingival recessions. Fourteen facial recessions in nine patients were subjected to a coronally repositioned flap in combination with a bioresorbable membrane, and 14 sites in 13 patients were treated with a connective tissue graft employing an envelope technique. Immediately before surgery and after 6 and 12 months, gingival dimensions as well as root coverage and attachment gain were assessed. At baseline, mean recession depths amounted to 2.77+/-1.67 mm and 2.49+/-1.07 mm for patients treated with a bioresorbable membrane and a free connective tissue graft, respectively. Acceptable and stable root coverage of 81% to 82% of baseline recession depth and 78% of its width was achieved by grafting. In contrast, guided tissue regeneration (GTR) resulted in only 50% coverage of recession depth and, after 12 months, only 11% of its width (P < 0.01). Logistic regression revealed that the odds of obtaining success, ie, at least 80% root coverage, were 3.3 times greater in cases treated with a connective tissue graft (P < 0.05). In addition, the odds ratio was 2.3 in cases of recessions below 2.5 mm compared to deeper recessions and 2 at canines compared to premolars. It was concluded that shallow recessions in the 1.5 to 3.5 mm range should not be treated with GTR. In these situations, predictable results are achieved with free connective tissue grafts employing an envelope technique.

Intraoral distribution of Actinobacillus actinomycetemcomitans in young adults with minimal periodontal disease

The aim of the present study was to investigate the intraoral distribution of Actinobacillus actinomycetemcomitans in young adults with minor signs of periodontal disease but harboring the organisms in the oral cavity. 17 healthy volunteers, 20 to 27 years of age, participated. Samples from mucosal surfaces of the oro-pharyngeal cavity and saliva (n = 221) as well as subgingival plaque from every tooth (n =477) were selectively cultivated for A. actinomycetemcomitans. Species identity and presence of the leukotoxin encoding gene, ltxA, were checked by multiplex polymerase chain reaction. Moreover, the leukotoxin promoter region was analyzed. No isolate harbored a 530 bp deletion in the promoter region of the leukotoxin gene, signaling minimally toxic strains. 42.1 +/- 30.4% extracrevicular and 34.4 +/- 29.5% subgingival samples were culture-positive. In extracrevicular samples, the organism could easily be recovered from cheek mucosa (62%), saliva (59%) and the palatal tonsils (41%). Mean log-transformed numbers of A. actinomycetecomitans colony forming units (CFU/ml) in culture-positive material ranged between 1.8 from the hard palate and 2.3 from 10 microl saliva. The highest prevalence in subgingival plaque was observed at maxillary 3rd molars (55%) followed by maxillary lateral incisors (50%) and mandibular 3rd molars (41%). Mean log-transformed counts of CFU/ml ranged between 2.2 at maxillary 3rd molars and 3.4 at upper central incisors. When adjusted for jaw, site and tooth type, the odds of isolating higher numbers of the organism were increased with every mm probing depth by a factor of 1.35 (p <0.05). The odds ratio for bleeding on probing was 1.38. Thus, in this young adult population with minor periodontal disease, A. actinomyetemcomitans was mainly associated with some deviation from gingival health. Of concern might be a minority of subjects (29%) with an extremely wide distribution of the organism in the oral cavity.

Acute fascioliasis with multiple liver abscesses

Human fascioliasis is distributed worldwide with several foci of high endemicity. Being a rare disease in Europe, we describe here a case in the initial hepatic phase of the disease. Therapeutic and, with reference to the 2 distinct stages of disease, diagnostic standards are discussed.

Protection induced in mice vaccinated with recombinant collagen-binding protein (CnBP) and alpha-toxoid against intramammary infection with Staphylococcus aureus

Mice vaccinated with a combination of two Staphylococcus aureus antigens consisting of a recombinant collagen-binding protein (CnBP) and alpha-toxoid (alpha-toxoid) were significantly protected from intramammary challenge infection with S. aureus. The average number of bacteria recovered from the glands of mice vaccinated with the combination of CnBP/alpha-toxoid was significantly lower compared to the average number of bacteria recovered from the glands of mice vaccinated with only CnBP or alpha-toxoid or controls (P< or =0.01). Histopathological examination of mammary glands of mice vaccinated with CnBP together with alpha-toxoid showed no pathological changes, whereas glands of mice vaccinated with CnBP or alpha-toxoid alone developed severe mastitis and showed both focal and disseminated necrosis.

ApoE-containing high density lipoproteins and phospholipid transfer protein activity increase in patients with a systemic inflammatory response

High density lipoproteins (HDL) mediate reverse cholesterol transport as well as the clearance of oxidation products or inflammatory mediators, thereby contributing to tissue integrity. The decrease in HDL in inflammation has been attributed to decreased lecithin:cholesterol acyltransferase activity, whereas the role of phospholipid transfer protein (PLTP) and cholesteryl ester transfer protein has not been analyzed in detail. We have studied the activities of HDL-modifying proteins and the heterogeneity of HDL in healthy control subjects and three groups of postsurgery patients: no bacterial infection (group 1), bacterial focus and systemic inflammatory response (group 2), and severe sepsis (group 3). For all patients, a decrease in total HDL could be demonstrated, with a loss of mainly large, apolipoprotein A-I (apoA-I) HDL particles, an almost total loss of apoC-I, and an increase in apoE HDL (200-500 kDa), which did not contain significant amounts of apoA-I, apoA-II, or apoC-I. PLTP activity was increased in patients of groups 2 and 3, paralleled by a redistribution of PLTP into a population of small (120- to 200-kDa) particles, probably representing PLTP homodimers or lipid-complexed PLTP. In summary, the increase in apoE HDL and PLTP activity may improve the delivery of energy substrates and phospholipids to tissues that must maintain cellular membrane homeostasis under conditions of inflammatory stress.

Site-specific association between supragingival plaque and bleeding upon probing in young adults

The aim of the present study was to consider supragingival plaque as a risk factor for gingivitis in a group of young adults without destructive periodontal disease. A total of 127 subjects, 17 to 30 years of age, participated. Periodontal probing depth, clinical attachment level as well as bleeding upon probing and supragingival plaque was assessed at 6 sites of every tooth present. The individual odds ratios between plaque and bleeding ranged between 0.237 and 66.6. 23% volunteers had an odds ratio of below 1.2. Only 15% individuals presented with an attributable risk of supragingival plaque for bleeding upon probing of 50% or more. Overall, the odds of bleeding, adjusted for periodontal probing depth, was increased by 67% in the presence of plaque. Large differences were observed at different teeth with the highest odds ratio at mandibular premolars with 2.557 (95% confidence interval 2.033-3.216) and the lowest at maxillary molars with 1.355 (1.161-1.732). It was concluded that there was high interindividual and intraindividual variation of the relative risk for bleeding in the presence of plaque. The observed low overall relative risk has important consequences in educational and health care programmes since the risk of supragingival plaque which is actually attributable for the observed bleeding on probing may be rather small.

Masticatory mucosa in subjects with different periodontal phenotypes

AIMS

The aim of the present investigation was to study thickness of masticatory mucosa and gingival width in subjects with different periodontal phenotypes.

METHODS

Periodontal phenotypes were defined with the aid of cluster analysis of standardised parameters including mean gingival thickness and width as well as ratio of crown width to its length at maxillary canines, lateral and central incisors of 40 young adults with healthy periodontal conditions.

RESULTS

3 groupings could be observed. Clusters A1 and A2 comprised 75% of all subjects. They were characterised by thin gingiva and a slender tooth form. Clusters A1 and A2 were differentiated by gingival width. Cluster B comprised 11 subjects with relatively thick and wide gingiva and a quadratic tooth shape. In general, characteristics of the frontal sextant in the maxilla were also found in other parts of the dentition. Thus, mean thickness of masticatory mucosa as well as gingival width and crown form differed significantly among clusters. In addition, cluster B subjects had a significantly greater mean periodontal probing depth. Multiple linear regression analysis was employed to identify significant factors influencing palatal mucosal thickness. Women had considerably thinner palatal mucosa than men. Furthermore, cluster affiliation had a significant influence on thickness of palatal mucosa. Thickest tissue was found in the premolar region, whereas the mucosa over the root prominence of the first molar represented an anatomical barrier for graft harvesting.

CONCLUSIONS

Thickness of masticatory mucosa strongly depends on gender and the periodontal phenotype.

[Smoking and periodontal health]

The causal agents of destructive periodontal disease are several gram-negative bacteria. The mere presence, however, in the dental biofilm does not guarantee onset of the disease. The immunological and inflammatory host response as well as connective tissue and bone metabolism are strongly influenced by genetic, acquired and behavioural risk factors. Among the last, tobacco consumption holds a primary position. Prevalence, extent and severity of periodontitis as well as tooth loss and edentulism are influenced by tobacco consumption in a dose-dependent manner. About 50% of periodontal disease in young adults is attributable to cigarette smoking. Postoperative results in periodontally diseased smokers are considerably poorer than those achieved in non-smokers. As a consequence smoking cessation has to be in corporated in traditional treatment concepts for inflammatory periodontal disease.

Thickness of masticatory mucosa

BACKGROUND

The aim of the present study was to assess thickness of all parts of the masticatory mucosa by using an ultrasonic measuring device.

METHODS

A total of 40 periodontally healthy subjects, 19 to 30 years old, took part. Thickness of masticatory mucosa was measured at a maximum of 149 sites in each proband.

RESULTS

Female volunteers had significantly thinner mean masticatory mucosa than males (p<0.01). Mean thickness of facial gingiva ranged between 0.7 mm at canines in the maxilla and central incisors in the mandible and 2.3 mm at 3rd molars in the mandible. In the mandible, thickness of lingual gingiva ranged between 0.9 mm at lateral incisors and 2.3 mm at 3rd molars. Interdental gingiva ranged between 1.0 mm 2.1 mm. With 3 mm or more, on average, palatal masticatory mucosa was thickest in the 3rd molar region and at 2nd premolars at more central locations. 2 regions with comparatively thin palatal mucosa of about 2 mm were identified, namely (i) at central and lateral incisors and (ii) at the prominence of the palatal roots of 1st and 2nd molars. The thickest tissue with more than 4 mm, on average, was observed in the tuberosity and retromolar regions.

CONCLUSIONS

Considerable intra- as well as interindividual variation of thickness of masticatory mucosa could be observed. According to differences in thickness of facial and interdental gingiva, it appears that lining is also an important function of the gingiva in reducing and smoothing the pronounced convexities of the dentoalveolar, i.e., skeletal, complex.

Dynamics of mucosal dimensions after root coverage with a bioresorbable membrane

BACKGROUND

So far, the clinical effects of the placement of a resorbable membrane for guided tissue regeneration have not been studied in humans in great detail. The dynamics of the resorptive processes, in particular, appear to be rather speculative. In the present longitudinal study, specific alterations of the dimensions of the dentogingival mucosa were explored after surgical root coverage by using a bioresorbable membrane and a coronally-repositioned flap.

METHODS

The study population consisted of 14 patients with a total of 31 predominantly shallow, Miller class I, II or III recessions. The thickness of the masticatory and lining mucosa before and after surgical intervention was measured with an ultrasonic device.

RESULTS

Mean (+/-sd) recession depth and width were 2.85+/-1.29 and 4.46+/-1.14 mm, respectively. After 12 months, 51+/-29% of the recession depth (p<0.001) and 13+/-35% of its width (n.s.) were covered. Root coverage seems to be rather defect-type sensitive with best results obtained at canines with relatively shallow recessions. Mucosal thickness was considerably increased after surgery with a gradual decrease during the following 9 months. Thus, thickness of the marginal tissue rose from 0.82+/-0.27 mm to 1.49+/-0.54 mm 3 months after placement of the membrane (p<0.001). After 12 months, a mean thickness of 1.03+/-0.40 mm was observed (p<0.001). Even more pronounced alterations were noted for the alveolar lining mucosa with a threefold increase of thickness 3 months after surgery and a gradual decrease to about 1 mm after 12 months.

CONCLUSIONS

The present results point to the considerable space making capacity of the bioresorbable membrane which probably allows for the ingrowth of a granulation tissue derived from the underlying structures. The gradual decline in mucosal thickness between months 6 and 9 after surgery may be paralleled by the maturation of the granulation tissue while complete resorption of the membrane had been accomplished.

Absence of an especially toxic clone among isolates of Actinobacillus actinomycetemcomitans recovered from army recruits

Actinobacillus actinomycetemcomitans is a major periodontal pathogen which is associated with early-onset and adult periodontitis. The organism has been shown to be widely distributed among dentate, healthy individuals as well. It has been demonstrated that A. actinomycetemcomitans shows great genetic diversity. An especially virulent clone of the organism (JP2-like) with a specific 530-base pair (bp) deletion in the promoter region of the leukotoxin gene has been isolated from localized juvenile periodontitis patients and related subjects of African and African-American origin. The aim of the present study was to examine the presence of this specific clone employing specific oligonucleotide primers in a polymerase chain reaction among 51 isolates of A. actinomycetemcomitans recovered from 201, 18- to 25-year-old recruits with no or minor periodontal disease. In addition, clinical isolates from 37 periodontitis patients were analyzed as well as reference strains ATCC 29524, NCTC 9710, Y4 and JP2. Primers amplifying a specific 285-bp amplification product in the ltxA region of the leukotoxin gene and a specific 547-bp amplification product of 16 S rRNA were used to genetically confirm identification of the organisms. Primers amplifying sequences in the leukotoxin promoter region were used to identify the deletion. Species specific primers definitively identified all A. actinomycetemcomitans isolates. No isolates from army recruits or the reference strains displayed the deletion in the leukotoxin promoter region. However, in the periodontitis group, a 24-year-old individual from Ghana with localized juvenile periodontitis was identified with an intraoral infection with highly toxic A. actinomycetemcomitans (JP2-like). Present results confirm previous observations of absence of a highly toxic clone of A. actinomycetemcomitans among periodontally healthy and diseased Caucasians as well as a possible presence in localized juvenile periodontitis in individuals of African origin.

Ultrasonic determination of thickness of masticatory mucosa: a methodologic study

OBJECTIVE

The aim of the present study was to assess the reliability and validity of ultrasonic measurements of thickness of the masticatory mucosa.

STUDY DESIGN

Eleven periodontally healthy subjects took part. Thickness of the buccal gingiva was assessed midbuccally and interdentally. In the maxilla, the palatal mucosa was measured at every tooth midpalatally, between the first and second molars, and between the second and third molars at each of 3 defined locations 4 mm apart. In the mandible, thickness of the lingual gingiva was measured midlingually as well as interdentally between the first and second molars and between the second and third molars. Thickness of the retromolar mucosa was also assessed. All 1,293 measurements were repeated after 24 hours. Validity of measurements was tested in a porcine model.

RESULTS

Mean (+/- standard deviation) thickness of the midbuccal and midlingual gingiva was 0.99+/-0.52 mm; the measurement error was 0.26 mm. Measurements were well correlated (Pearson's r = .74, P<.001). Mean thickness of the papillary gingiva was 1.19+/-0.53 mm; the measurement error was 0.37 mm (r = .58, P<.001). A lower reliability was observed for palatal measurements of mucosal thickness; mean thickness was 2.36+/-0.87 mm, and measurement error was 0.54 mm (r = .64, P<.001). The validity of measurements was excellent in the 0.5-4.5 mm range.

CONCLUSIONS

Differences in reliability of ultrasonic assessments of mucosal thickness in different parts of the oral cavity may depend on the difficulties of repeatedly measuring at the same location, on varying thickness of the tissues, and on expression of palatal rugae. These problems might be resolved by averaging multiple measurements.

Furcation diagnosis

One of the most important and at present unsolved problems in clinical periodontology is the predictable successful treatment of periodontitis-affected furcations of multirooted teeth. Since several therapeutic approaches are proposed, i.e., conservative, resective or regenerative, a proper diagnosis of these lesions is demanding. The aim of the present article is to review the current information on the impact of a proper diagnosis of a furcational lesion as well as tooth morphology on decision making with regard to different treatment modalities and to emphasize the need for a detailed clinical, radiographical and intraoperative diagnosis of the furcation lesion beyond the usually performed diagnosis of the degree of furcation involvement.

Root coverage employing an envelope technique or guided tissue regeneration with a bioabsorbable membrane

BACKGROUND

Different treatment modalities have been described for root coverage in cases of gingival recession. The aim of the present study was to evaluate the postsurgical outcome of 2 modes of surgical root coverage of predominantly shallow, Class I or II, gingival recessions.

METHODS

Fourteen buccal recession sites in 13 patients were treated with free connective tissue grafts employing a modified envelope technique; 14 sites in 9 patients were subjected to a coronally repositioned flap in combination with a bioabsorbable membrane. Immediately before surgery as well as after 6 months, gingival dimensions, i.e., width and thickness, as well as root coverage and attachment gain, were assessed to the next 0.1 mm employing a caliper, an ultrasonic device, and a pressure calibrated, computerized periodontal probe.

RESULTS

At the outset, mean recession depths amounted to 2.48+/-1.06 and 3.00+/-1.95 mm for patients treated with a free connective tissue graft and a bioabsorbable membrane, respectively. With the former technique, 80+/-24% root surface could be covered after 6 months, while the latter resulted in only 45+/-40% coverage. The contrast in reduction of recession width was even more pronounced (77+/-35% versus 18+/-37%). In both groups, an increase of gingival thickness of 0.6 to 0.7 mm was noticed.

CONCLUSIONS

Small recessions may be covered more predictably with the modified envelope technique. 751.

Protein GRAB of streptococcus pyogenes regulates proteolysis at the bacterial surface by binding alpha2-macroglobulin

In the molecular interplay between pathogenic microorganisms and their host, proteolytic mechanisms are believed to play a crucial role. Here we find that the important human pathogen Streptococcus pyogenes (group A Streptococcus) expresses a surface protein with high affinity (Ka = 2.0 x 10(8) M-1) for alpha2-macroglobulin (alpha2M), the dominating proteinase inhibitor of human plasma. The immunoglobulin-binding protein G of group C and G streptococci also contains an alpha2M-binding domain and a gene encoding protein GRAB (protein G-related alpha2M-binding protein) was identified in the S. pyogenes Genome Sequencing data base. The grab gene is present in most S. pyogenes strains and is well conserved. Protein GRAB has typical features of a surface-attached protein of Gram-positive bacteria. It also contains a region homologous to parts of the alpha2M-binding domain of protein G and a variable number of a unique 28-amino acid-long repeat. Using Escherichia coli-produced protein GRAB and synthetic GRAB peptides, the alpha2M-binding region was mapped to the NH2-terminal part of protein GRAB, which is the region with homology to protein G. An isogenic S. pyogenes mutant lacking surface-associated protein GRAB showed no alpha2M binding activity and was attenuated in virulence when injected intraperitoneally in mice. Finally, alpha2M bound to the bacterial surface via protein GRAB was found to entrap and inhibit the activity of both S. pyogenes and host proteinases, thereby protecting important virulence determinants from proteolytic degradation. This regulation of proteolytic activity at the bacterial surface should affect the host-microbe relation during S. pyogenes infections.

Clonal diversity of Actinobacillus actinomycetemcomitans isolates from young adults with minimal periodontal disease

Actinobacillus actinomycetemcomitans is a major periodontal pathogen which is associated with both early-onset periodontitis and adult cases refractory to conventional periodontal therapy, although the organism has also been shown to be widely distributed among dentate healthy individuals. The observed disease status may be associated with a variation in virulence of different strains or clones. The aim of the present study was to analyse genotype distribution as assessed by an arbitrarily primed polymerase chain reaction (AP-PCR) among 51 isolates of A. actinomycetemcomitans recovered from more than 200 young adult recruits with no or minor periodontal disease. In addition, isolates from 25 periodontitis patients as well as reference strains were genotyped. Primers amplifying (i) a specific sequence in the ltxA region, (ii) a specific 16S rRNA sequence and (iii) sequences in the leukotoxin promoter region were used to verify species identity of the strains. Three random oligonucleotide primers were employed to analyse genomic polymorphisms of the organism by means of PCR. A total of 19 genotypes could be distinguished, which were grouped by cluster analysis into 5 major clusters based on genetic similarity and a complete linkage sort. Whereas 3 clusters assembled A. actinomycetemcomitans genotypes isolated from both healthy subjects and periodontitis patients, one cluster containing 4 different genotypes exclusively comprised isolates from healthy or gingivitis subjects. Another cluster with 2 genotypes consisted of strains originating from periodontitis patients (p < 0.05). One strain characterized by a specific 530 bp deletion in the promoter region of the leukotoxin region was identified in a Ghanese patient with localized juvenile periodontitis. It was concluded that there is considerable clonal diversity of A. actinomycetemcomitans strains isolated from healthy or periodontally diseased subjects, and that genetically closely related groups might be associated with health or disease.

Localization of a ventricular tachycardia-focus with multichannel magnetocardiography and three-dimensional current density reconstruction

The objective of this case report is to determine the accurate localization of a malignant ventricular tachycardia (VT) focus by combining multichannel magnetocardiographic (MCG) information with morphologic data. The localization was obtained by calculating the three-dimensional current density distribution (3D-CDD) on the left ventricular surface. To estimate the accuracy of this localization technique, examinations of a healthy volunteer were additionally performed. The MCG-signals were recorded in a magnetically shielded room by a 49-channel magnetogradiometer. The corresponding morphologic information was recorded by magnetic resonance tomography (MRT). The coordinate systems were matched with the help of markers. The 3D-CDD was calculated by the Philips CURRY software package. The origin of a malignant VT determined by X-ray images of the ablation catheter position during the electrophysiological examination (EPE), was used as the gold standard. This was then compared with the localization results obtained by the 3D-CDD. It was found that the localization coordinates showed a difference of less than 10 mm.

Cemental tear treated with guided tissue regeneration: a case report 3 years after initial treatment

Cemental tear is a rare but probably underdiagnosed condition that may be a factor in rapid periodontal breakdown. The present case report describes the regenerative treatment of a periodontal lesion around a mandibular canine in a 50-year-old woman. The preoperative radiograph revealed a small cemental tear within an intrabony lesion. The three-wall bony lesion was treated with a barrier membrane and followed for 3 years. Periodontal pocket reduction was 5.5 mm, and attachment gain amounted to 3.5 to 4.5 mm Standardized radiographs showed remarkable, 1.6-mm bone fill of the intrabony lesion. Also, a band of keratinized tissue had formed.