High-Performance Bioinspired Microspheres for Boosting Dental Adhesion.

Dental adhesives are widely used in daily practice for minimally invasive restorative dentistry but suffer from bond degradation and biofilm attack. Bio-inspired by marine mussels having excellent surface-adhesion capability and high chemical affinity of polydopamine (PDA) to metal ions, herein, experimental zinc (Zn)-containing polydopamine-based adhesive formulation, further being referred to as "Zn-PDA@SiO2"-incorporated adhesive is proposed as a novel dental adhesive. Different Zn contents (5 and 10 mm) of Zn-PDA@SiO2 are prepared. Considering the synergistic effect of Zn and PDA, Zn-PDA@SiO2 not only presents excellent antibacterial potential and notably inhibits enzymatic activity (soluble and matrix-bound proteases), but also exhibits superior biocompatibility and biosafety in vitro/vivo. The long-term bond stability is substantially improved by adding 5 wt% 5 mm Zn-PDA@SiO2 to the primer. The aged bond strength of the experimentally formulated dental adhesives applied in self-etch (SE) bonding mode is 1.9 times higher than that of the SE gold-standard adhesive. Molecular dynamics calculations indicate the stable formation of covalent bonds, Zn-assisted coordinative bonds, and hydrogen bonds between PDA and collagen. Overall, this bioinspired dental adhesive provides an avenue technology for innovative biomedical applications and has already revealed promising perspectives for dental restorative dentistry.

Computer-assisted navigation for removal of the foreign body in the lower jaw with a mandible reference frame: A case report.

RATIONALE: In surgery of the lower jaw, the application of computer-assisted navigation is complicated and challenging due to the mobile nature of the mandible. In this study, we presented a computer-assisted navigation surgery for removal of the foreign body in the lower jaw with a mandible reference frame, basing on the strategy that the mandible is independent as an entity. PATIENT CONCERNS: A 41-year-old male patient, identified as having a broken fissure bur that displaced into the mandibular lingual soft tissue, was referred to our department. The fissure bur broke accidentally and then displaced into the soft tissue when the patient underwent extraction of the left mandibular impacted third molar. DIAGNOSIS: A metallic foreign body in the left lower jaw, confirmed by orthopantomography. INTERVENTIONS: A computer-assisted navigation surgery with a customized mandible reference frame. OUTCOMES: The broken bur was removed successfully. Satisfactory wound healing and mouth opening was achieved, without postoperative complications. LESSONS: Surgeons should be alert to the presence of broken bur in the lower jaw and avoid its displacement into deep facial space, and computer-assisted navigation with a mandible reference frame is recommended for removal of the foreign body in the lower jaw.

Lifestyle factors of people with exceptional longevity.

OBJECTIVES: To assess lifestyle factors including physical activity, smoking, alcohol consumption, and dietary habits in men and women with exceptional longevity. DESIGN: Retrospective cohort study. SETTING: A cohort of community-dwelling Ashkenazi Jewish individuals with exceptional longevity defined as survival and living independently at age 95 and older. PARTICIPANTS: Four hundred seventy-seven individuals (mean 97.3 ± 2.8, range 95-109; 74.6% women) and a subset of participants of the National Health and Nutrition Examination Survey (NHANES) I (n = 3,164) representing the same birth cohort as a comparison group. MEASUREMENTS: A trained interviewer administrated study questionnaires to collect information on lifestyle factors and collected data on anthropometry. RESULTS: People with exceptional longevity had similar mean body mass index (men, 25.4 ± 2.8 kg/m² vs 25.6 ± 4.0 kg/m² , P=.63; women, 25.0 ± 3.5 kg/m² vs 24.9 ± 5.4 kg/m² ; P = .90) and a similar proportion of daily alcohol consumption (men, 23.9 vs 22.4, P = .77; women, 12.1 vs 11.3, P = .80), of regular physical activity (men: 43.1 vs 57.2; P = .07; women: 47.0 vs 44.1, P = .76), and of a low-calorie diet (men: 20.8 vs 21.1, P=.32; women: 27.3 vs 27.1, P=.14) as the NHANES I population. CONCLUSION: People with exceptional longevity are not distinct in terms of lifestyle factors from the general population, suggesting that people with exceptional longevity may interact with environmental factors differently than others. This requires further investigation.

Thyroid hormone promotes remodeling of coronary resistance vessels.

Low thyroid hormone (TH) function has been linked to impaired coronary blood flow, reduced density of small arterioles, and heart failure. Nonetheless, little is known about the mechanisms by which THs regulate coronary microvascular remodeling. The current study examined the initial cellular events associated with coronary remodeling induced by triiodothyronine (T3) in hypothyroid rats. Rats with established hypothyroidism, eight weeks after surgical thyroidectomy (TX), were treated with T3 for 36 or 72 hours. The early effects of T3 treatment on coronary microvasculature were examined morphometrically. Gene expression changes in the heart were assessed by quantitative PCR Array. Hypothyroidism resulted in arteriolar atrophy in the left ventricle. T3 treatment rapidly induced small arteriolar muscularization and, within 72 hours, restored arteriolar density to control levels. Total length of the capillary network was not affected by TX or T3 treatment. T3 treatment resulted in the coordinate regulation of Angiopoietin 1 and 2 expression. The response of Angiopoietins was consistent with vessel enlargement. In addition to the well known effects of THs on vasoreactivity, these results suggest that THs may affect function of small resistance arteries by phenotypic remodeling of vascular smooth muscle cells (VSMC).

Regulation of arteriolar density in adult myocardium during low thyroid conditions.

Low thyroid function induced by either propylthiouracil (PTU) treatment or thyroidectomy surgery led to a reduction of arteriolar density in adult rat myocardium, which can be prevented by treatment with thyroxine or the thyroid hormone analogue 3,5-diiodothyropropionic acid (DITPA). However, many questions related to pathophysiological changes and the regulation of arteriolar density in the heart due to hypothyroidism remain unanswered. Sprague-Dawley rats were treated with PTU in drinking water for 1, 3, and 6weeks, or co-treated with the vasodilator dipyridamole and PTU for 6weeks, or treated with PTU for 6weeks and treatment discontinued for 2 or 4weeks. Heart mass, body mass, cardiac function and myocardial arteriolar density were determined. Arteriolar loss in hypothyroidism induced by PTU treatment progressed gradually with a 22% reduction after 3weeks treatment and 34% by 6weeks which was largely reversed after discontinuing PTU treatment for only 2weeks. Combined treatment with the vasodilator dipyridamole during the 6-week PTU treatment period prevented vessel loss indicating the mechanism of arteriolar loss from hypothyroidism may result from vasoconstriction. These results suggest that thyroid hormone is a powerful regulator of vasculature in adult myocardium, particularly in low thyroid states.

Thyroid hormone analog 3,5-diiodothyropropionic acid promotes healthy vasculature in the adult myocardium independent of thyroid effects on cardiac function.

Patients with hypothyroidism are at a higher risk for coronary vascular disease. Patients with diabetes and related vascular complications also have an increased incidence of low thyroid function. While thyroid hormones (THs) may be key regulators of a healthy vasculature, potential undesirable side effects hinder their use in the treatment of vascular disorders. TH analogs such as 3,5-diiodothyropropionic acid (DITPA) may provide a safer treatment option. However, the relative potency of DITPA on vascular growth, cardiac function, and metabolism is poorly understood. We hypothesized that the vascular growth-promoting effects of DITPA can be obtained with a minimum effect on cardiac function. Thyroidectomized Sprague-Dawley rats were given slow-release pellets with either thyroxine (T4, 2.7 or 5.2 mg) or DITPA (80 mg) for 6 wk and were compared with placebo. Heart mass, body mass, body temperature, serum THs, cardiac function (echocardiograms and hemodynamics), and myocardial arteriolar density were determined. Hypothyroidism led to reductions in cardiac function, heart mass, body temperature, and myocardial arterioles. High-dose T4 prevented arteriolar loss and the development of hypothyroidism. Low-dose T4 partially prevented the reduction in cardiac function but had minimal effects on arteriolar loss. In contrast, DITPA treatment prevented myocardial arteriolar loss but not the progression of hypothyroid-induced changes in cardiac function. The results suggested that DITPA can promote a healthy vasculature independently from its thyroid-related metabolic effects. Drugs in this class may provide new therapeutic options for patients with vascular disease.

Effects of thyroidectomy, T4, and DITPA replacement on brain blood vessel density in adult rats.

In hypothyroid patients, altered microvascular structure and function may affect mood and cognitive function. We hypothesized that adult male hypothyroid rats will have significantly lower forebrain blood vessel densities (BVD) than euthyroid rats and that treatment with 3,5-diiothyroprionic acid (DITPA) (a thyroid hormone analog) or thyroxine (T(4)) will normalize BVDs. The euthyroid group received no thyroidectomy or treatment. The other three groups received thyroidectomies and pellets. The hypothyroid group received a placebo pellet, the DITPA group received an 80-mg DITPA-containing pellet, and the T(4) group received a 5.2-mg T(4) slow-release pellet for 6 wk. Body weights, cardiac function, and body temperatures were measured. A monoclonal antiplatelet endothelial cell adhesion antibody was used to visualize blood vessels. The euthyroid group averaged body weights of 548 +/- 54 g, while the hypothyroid group averaged a body weight of 332 +/- 19 g (P value < 0.001). Relative to the euthyroid group, the DITPA-treated group was significantly lighter (P value < 0.05), while the T(4)-treated group was comparable in body weight to the euthyroid group. The same trends were seen with body temperature and cardiac function with the largest difference between the euthyroid and hypothyroid groups. BVD in the euthyroid group was 147 +/- 12 blood vessels/mm(2) and in hypothyroid group 69 +/- 5 blood vessels/mm(2) (P = 0.013) but similar among the euthyroid, DITPA, and T(4) groups. These results show that hypothyroidism decreased BVD in adult rat forebrain regions. Moreover, DITPA and T(4) were efficacious in preventing effects of hypothyroidism on cardiac function and BVD.

Serum thyroid hormone levels may not accurately reflect thyroid tissue levels and cardiac function in mild hypothyroidism.

The link between thyroid dysfunction and cardiovascular diseases has been recognized for more than 100 years. Although overt hypothyroidism leads to impaired cardiac function and possibly heart failure, the cardiovascular consequences of borderline low thyroid function are not clear. Establishment of a suitable animal model would be helpful. In this study, we characterized a rat model to study the relationship between cardiovascular function and graded levels of thyroid activity. We used rats with surgical thyroidectomy and subcutaneous implantation of slow release pellets with three different T(4) doses for 3 wk. In terminal experiments, cardiac function was evaluated by echocardiograms and hemodynamics. Myocardial arteriolar density was also quantified morphometrically. Thyroid hormone levels in serum and heart tissue were determined by RIA assays. Thyroidectomy alone led to cardiac atrophy, severe cardiac dysfunction, and a dramatic loss of arterioles. The low T(4) dose normalized serum T(3) and T(4) levels, but cardiac tissue T(3) and T(4) remained below normal. Low-dose T(4) failed to prevent cardiac atrophy or restore cardiac function and arteriolar density to normal values. All cardiac function parameters and myocardial arteriolar density were normalized with the middle dose of T(4), whereas the high dose produced hyperthyroidism. Our results show that thyroid hormones are important regulators of cardiac function and myocardial arteriolar density. This animal model will be useful in studying the pathophysiological consequences of mild thyroid dysfunction. Results also suggest that cardiac function may provide valuable supplemental information in proper diagnosis of mild thyroid conditions.