Regeneration of surgically removed buccal alveolar bone in dogs

The aim of the present study was to examine if the establishment of a new fibrous attachment to the root surfaces is accompanied by regeneration of surgically romoved buccal alveolar bone.
The experiments were carried out in two dogs with healthy periodontal conditions. The marginal 5–7 mm of the buccal alveolar bone between the mesial and distal line angles of each root of one maxillary second and one mandibular third premolar in both dogs was removed after elevation of a muco-peristeal flap. During this procedure attempts were made to minimize the mechanica injury to the root cementum and the supraalveolar connective tissue attachment. A notch was prepared in the root surfaces at the level of teh surgically esablished bone crest. This notch served as a landmark for measurements to be made in histological sections. The flaps were repositioned and sutured with interrupted mattress sutures. During the entire experimental period, meticulous plaque control was maintained. In each dog. the contralateral teeth served as non-treated controls. The animals were sacrificed 8 months after sugery and sections of all test-and control areas prepared for light microscopic examination.
The results of the study demonstrated that in all experimental areas, new cementum formation and fibrous reattachment occurred in the supraalveolar area between the marginal bone crest and teh junctional epithlium. In only two out of eight test areas did the alveolar bone regenerate to or close ot the normal distance from the apical portion of the junctional epithelium whereas in the remaining six areas, a long supracrestal connective tissue attachment was present.     

Under-five mortality in the Democratic Republic of the Congo: secondary analyses of survey and conflict data by province

ObjectiveTo compare coverage of key child health policy indicators across provinces and to explore their association with under-five mortality and level of conflict in the Democratic Republic of the Congo.MethodsWe made a secondary analysis of nationally representative data from 1380 health facilities and 20 792 households in 2017–2018. We analysed provincial-level data on coverage of 23 different indicators for improving common causes of childhood mortality, combined into mean scores for: newborn health, pneumonia, diarrhoea, malaria and safe environment. Using negative binomial regression we compared the scores with provincial-level under-five mortality. With binary logistic regression at the individual level we compared indicators (outcome) with living in a conflict-affected province (exposure).FindingsAll grouped coverage scores demonstrated large ranges across the 26 provinces: newborn health: 20% to 61%; pneumonia: 26% to 86%; diarrhoea: 25% to 63%; malaria: 22% to 53%; and safe environment: 4% to 53%. The diarrhoea score demonstrated the strongest association with under-five mortality (adjusted coefficient: −0.026; 95% confidence interval: −0.045 to −0.007). Conflict-affected provinces had both the highest as well as the lowest mortality rates and indicator coverages. The odds of coverage were higher in conflict-affected provinces for 13 out of 23 indicators, whereas in provinces unaffected by conflict only one indicator had higher odds of coverage.ConclusionConflict alone is a poor predictor for child health. Ensuring that children in unaffected provinces are not neglected while addressing the needs of the most vulnerable in conflict settings is important. Prevent, protect and treat strategies for diarrhoeal disease could help improve equity in child survival.     

Histological evaluation of healing after transalveolar maxillary sinus augmentation with bioglass and autogenous bone

Objectives: The aim was to evaluate histologically the outcome of a bioglass and autogenous bone (at 1 : 1 ratio) composite implantation for transalveolar sinus augmentation. Methods: In 31 patients, during implant installation ca. 4 months after sinus augmentation, biopsies were harvested through the transalveolar osteotomy by means of a trephine bur and non‐decalcified sections through the long axis of the cylinder were produced. After a strict selection process, taking into account the presurgical residual bone height and biopsy length, 8 and 15 biopsies representing the new tissues formed inside the sinus and the transalveolar osteotomy, respectively, qualified for analysis. The tissue fractions occupied by newly formed bone (mineralized tissue+bone marrow), soft connective tissue, residual biomaterial+empty spaces, and debris inside the sinus cavity or the transalveolar osteotomy were estimated. Results: Bone and connective tissue fraction in the newly formed tissues inside the sinus cavity averaged 23.4 ± 13.2% and 54.1 ± 23.5%, respectively. Residual biomaterial, empty spaces, and debris averaged 1.9 ± 3.5%, 10.5 ± 6.3%, and 8.4 ± 14.5%, respectively. In the transalveolar osteotomy, bone and connective tissue fraction averaged 41.6 ± 14.3% and 46.1 ± 13%, respectively, while the amount of residual biomaterial, empty spaces, and debris was 2.8 ± 5%, 4.7 ± 1.9%, and 3.2 ± 2.6%, respectively. Statistically significant differences between the sinus cavity and the transalveolar osteotomy were found only for bone and empty spaces' values (P=0.02 and 0.04, respectively). Conclusion: Sinus augmentation with a bioglass and autogenous bone composite is compatible with bone formation that, in a short distance from the floor of the sinus, shows similar density as that reported previously for other commonly used bone substitutes. New bone fraction inside the transalveolar osteotomy was almost twice as much as in the sinus cavity, while the amount of residual biomaterial was much less than that inside the sinus. To cite this article :
Stavropoulos A, Sima C, Sima A, Nyengaard J, Karring T, Sculean A. Histological evaluation of healing after transalveolar maxillary sinus augmentation with bioglass and autogenous bone.
Clin. Oral Impl. Res. 23 , 2012; 125–131.
doi: 10.1111/j.1600‐0501.2011.02161.x     

Change in Proportional Protein Intake in a 10-Week Energy-Restricted Low- or High-Fat Diet,in Relation to Changes in Body Size and Metabolic Factors

ObjectiveTo investigate in a secondary analysis of a randomised trial the effects of a low-/high-fat diet and reported change from baseline in energy% from protein (prot%), in relation to changes in body size and metabolic factors.MethodsObese adults (n = 771) were randomised to a 600 kcal energy-deficient low-fat (20-25 fat%) or high-fat (40-45 fat%) diet over 10 weeks. Dietary intake data at baseline and during the intervention were available in 585 completers. We used linear regression to calculate the combined effects of randomised group and groups of prot% change (<−2 /−2 to 2/>2) on outcomes.ResultsThe low-fat group with >2 prot% increase lost 1.1 kg more weight (p = 0.03) and reduced cholesterol by 0.25 mmol/l more (p = 0.003) than the high-fat group with >2 prot% decrease. These differences were 2.5-fold and 1.8-fold greater than the differences between the low-fat and high-fat groups while not considering prot% change. The high-fat group reduced plasma triglycerides more than the low-fat group, but not compared to those in the low-fat group with >2 units prot% increase (p fat-protein interaction = 0.01).ConclusionsUnder energy restriction, participants on a low-fat diet who had increased the percentage energy intake from protein showed the greatest reduction in weight and cholesterol, and a triglyceride reduction equally large to that of participants on a high-fat diet.Key Words: Obesity, Dietary fats, Dietary proteins, Lipids, Blood glucose     

Genetic and environmental influences on plasma homocysteine: results from a Danish twin study

BACKGROUND: Increased plasma homocysteine has been linked to many clinical conditions including atherosclerosis and ischemic stroke. We assessed the genetic and environmental influences on homocysteine in adult twins and tested the influence of 3 candidate polymorphisms. METHODS: Homocysteine was analyzed in 1206 healthy twins, who were genotyped for 3 polymorphisms: MTHFR 677C>T, MTR 2756A>G, and NNMT (dbSNP: rs694539). To perform quantitative trait linkage analysis of the MTHFR locus, the genotyping was supplemented with 2 genetic markers localized on each site of the MTHFR locus. The twin data were analyzed using biometric structural equation models as well as a combined association and linkage analysis in 2 age cohorts. RESULTS: Age, sex, and MTHFR genotype have a significant impact on homocysteine concentrations, whereas the other genotypes were not associated with homocysteine concentrations. The variance in homocysteine could be solely ascribed to additive genetic and nonshared environmental factors, with an estimated additive genetic proportion of total variation at age 18-39 years of 0.63 (95% CI, 0.53-0.71) and at age 40-65 years of 0.27 (95% CI, 0.10-0.41). The impact of the MTHFR locus is estimated to explain 53% (95% CI, 0.07-0.67) of the total phenotypic variation in persons 18-39 years old and 24% (95% CI, 0.00-0.39) in persons 40-65 years old, i.e., almost all additive genetic variance. CONCLUSIONS: Homocysteine concentrations have a high heritability that decreases with age. The MTHFR gene locus is responsible for almost all the variation attributable to genetic factors, leaving very little influence of other genetic variations.     

The Validation and Assessment of Machine Learning: A Game of Prediction from High-Dimensional Data

In applied statistics, tools from machine learning are popular for analyzing complex and high-dimensional data. However, few theoretical results are available that could guide to the appropriate machine learning tool in a new application. Initial development of an overall strategy thus often implies that multiple methods are tested and compared on the same set of data. This is particularly difficult in situations that are prone to over-fitting where the number of subjects is low compared to the number of potential predictors. The article presents a game which provides some grounds for conducting a fair model comparison. Each player selects a modeling strategy for predicting individual response from potential predictors. A strictly proper scoring rule, bootstrap cross-validation, and a set of rules are used to make the results obtained with different strategies comparable. To illustrate the ideas, the game is applied to data from the Nugenob Study where the aim is to predict the fat oxidation capacity based on conventional factors and high-dimensional metabolomics data. Three players have chosen to use support vector machines, LASSO, and random forests, respectively.     

Adverse effects of subthalamic nucleus DBS in a patient with multiple system atrophy

A 59-year-old woman with levodopa-responsive parkinsonism complicated by motor fluctuations and generalized levodopa dyskinesia underwent bilateral subthalamic deep brain stimulation (STN DBS) 7 years after symptom onset. DBS improved levodopa-responsive upper extremity bradykinesia but aggravated speech, swallowing, and gait. Motor fluctuations were not improved and levodopa dose remained unchanged. Pulse generators were turned off. Clinical features and brain MRI in this case were indicative of multiple system atrophy (MSA). STN DBS is not recommended for patients with MSA.