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1.
J Dent Res ; 103(5): 477-483, 2024 May.
Article in English | MEDLINE | ID: mdl-38504091

ABSTRACT

Existing studies on multimorbidity have largely excluded oral diseases in multimorbidity prevalence estimates. The reason behind this is somewhat unclear, as chronic oral conditions are highly prevalent, affecting over half the global population. To address this gap, we examined the relationship between social disadvantage and multimorbidity, stratifying by the inclusion and exclusion of oral conditions. For participants aged 30 y and over (n = 3,693), cross-sectional analysis was carried out using the US National Health and Nutrition Survey (2013-2014). Multimorbidity was defined as having 2 or more chronic conditions. Five medical conditions were examined: diabetes, asthma, arthritis, cardiovascular disease, and depression, as well as 4 oral health conditions: caries, periodontal disease, number of teeth, and edentulousness. Education and income poverty ratio were selected as measures of social disadvantage. Multimorbidity prevalence estimates according to social disadvantage were analyzed on an absolute and relative scale using inverse probability treatment weighting (IPTW), adjusting for age, sex, and ethnicity. The inclusion of oral health conditions in the assessment of multimorbidity increased the overall prevalence of multimorbidity from 20.8% to 53.4%. Findings from IPTW analysis demonstrated clear social gradients for multimorbidity estimates stratified by the exclusion of oral conditions. Upon inclusion of oral conditions, the prevalence of multimorbidity was higher across all social groups for both education and income. Stratifying by the inclusion of oral conditions, the mean probability of multimorbidity was 27% (95% confidence interval [CI], 23%-30%) higher in the low-education group compared to the high-education group. Similarly, the mean probability of multimorbidity was 44% (95% CI, 40%-48%) higher in the low-income group. On a relative scale, low education was associated with a 1.52 times (95% CI, 1.44-1.61) higher prevalence of multimorbidity compared to high education. Low income was associated with a 2.18 (95% CI, 1.99-2.39) higher prevalence of multimorbidity. This novel study strongly supports the impact of chronic oral conditions on multimorbidity prevalence estimates.


Subject(s)
Multimorbidity , Humans , United States/epidemiology , Female , Male , Middle Aged , Cross-Sectional Studies , Adult , Prevalence , Aged , Nutrition Surveys , Poverty/statistics & numerical data , Mouth Diseases/epidemiology , Chronic Disease/epidemiology , Oral Health/statistics & numerical data , Periodontal Diseases/epidemiology , Educational Status , Dental Caries/epidemiology , Socioeconomic Factors , Asthma/epidemiology , Depression/epidemiology , Diabetes Mellitus/epidemiology , Cardiovascular Diseases/epidemiology
2.
J Dent Res ; 102(8): 887-894, 2023 07.
Article in English | MEDLINE | ID: mdl-37085984

ABSTRACT

Social participation prevents social isolation and loneliness among older adults while having numerous positive effects on their health and well-being in rapidly aging societies. We aimed to estimate the effect of retaining more natural teeth on social participation among older adults in Japan. The analysis used longitudinal data from 24,872 participants in the Japan Gerontological Evaluation Study (2010, 2013, and 2016). We employed a longitudinal modified treatment policy approach to determine the effect of several hypothetical scenarios (preventive scenarios and tooth loss scenarios) on frequent social participation (1 = at least once a week/0 = less than once a week) after a 6-y follow-up. The corresponding statistical parameters were estimated using targeted minimum loss-based estimation (TMLE) method. Number of teeth category (edentate/1-9/10-19/≥20) was treated as a time-varying exposure, and the outcome estimates were adjusted for time-varying (income, self-rated health, marital status, instrumental activities of daily living, vision loss, hearing loss, major comorbidities, and number of household members) and time-invariant covariates (age, sex, education, baseline social participation). Less frequent social participation was associated with older age, male sex, lower income, low educational attainment, and poor self-rated health at the baseline. Social participation improved when tooth loss prevention scenarios were emulated. The best preventive scenario (i.e., maintaining ≥20 teeth among each participant) improved social participation by 8% (risk ratio [RR] = 1.08; 95% confidence interval [CI], 1.05-1.11). Emulated tooth loss scenarios gradually decreased social participation. A hypothetical scenario in which all the participants were edentate throughout the follow-up period resulted in a 11% (RR = 0.89; 95% CI, 0.84-0.94) reduction in social participation. Subsequent tooth loss scenarios showed 8% (RR = 0.92; 95% CI, 0.88-0.95), 6% (RR = 0.94; 95% CI, 0.91-0.97), and 4% (RR = 0.96; 95% CI, 0.93-0.98) reductions, respectively. Thus, among Japanese older adults, retaining a higher number of teeth positively affects their social participation, whereas being edentate or having a relatively lower number of teeth negatively affects their social participation.


Subject(s)
Tooth Loss , Humans , Male , Aged , Tooth Loss/epidemiology , Activities of Daily Living , Oral Health , Income , Aging , Japan
3.
J Dent Res ; 99(12): 1356-1362, 2020 11.
Article in English | MEDLINE | ID: mdl-32735476

ABSTRACT

Despite their prevalence and burdens, oral diseases are neglected in universal health coverage. In Japan, a 30% copayment (out of pocket) by the user and a 70% contribution by Japan's universal health insurance (JUHI) are required for dental and medical services. From the age of 70 y, an additional 10% is offered by JUHI (copayment, 20%; JUHI, 80%). This study aimed to investigate the effect of cost on dental service use among older adults under the current JUHI system. A regression discontinuity quasi-experimental method was used to investigate the causal effect of the JUHI discount policy on dental visits based on cross-sectional data. Data were derived from the 2016 Japan Gerontological Evaluation Study. This analysis contained 7,161 participants who used JUHI, were aged 68 to 73 y, and responded to questions regarding past dental visits. Analyses were controlled for age, sex, number of teeth, and equalized household income. Mean ± SD age was 72.1 ± 0.79 y for the discount-eligible group and 68.9 ± 0.78 y for the noneligible group. During the past 12 mo, significantly more discount-eligible participants had visited dental services than noneligible participants (66.0% vs. 62.1% for treatment visits, 57.7% vs. 53.1% for checkups). After controlling for covariates, the effect of discount eligibility was significant on dental treatment visits (odds ratio [OR], 1.36; 95% CI, 1.32 to 1.40) and dental checkups (OR, 1.49; 95% CI, 1.44 to 1.54) in the regression discontinuity analysis. Similar findings were observed in triangular kernel-weighted models (OR, 1.38 [95% CI, 1.34 to 1.44]; OR, 1.52 [95% CI, 1.47 to 1.56], respectively). JUHI copayment discount policy increases oral health service utilization among older Japanese. The price elasticity for dental checkup visits appears to be higher than for dental treatment visits. Hence, reforming the universal health coverage system to improve the affordability of relatively inexpensive preventive care could increase dental service utilization in Japan.


Subject(s)
Universal Health Insurance , Aged , Cross-Sectional Studies , Humans , Japan , Regression Analysis
4.
Br Dent J ; 226(1): 3-4, 2019 01 11.
Article in English | MEDLINE | ID: mdl-30631202
5.
Foot Ankle Surg ; 24(3): 208-212, 2018 Jun.
Article in English | MEDLINE | ID: mdl-29409214

ABSTRACT

BACKGROUND: A number of studies report on limitations of the screw arthrodesis in severe malalignment of the hindfoot, neuropathic deformity, poor bone quality and osteoporosis. METHODS: Fourteen anatomically correct polyurethane foam models of the right leg (Sawbones Europe, Malmö, Sweden) and eighteen fresh-frozen human lower leg specimens (9 pairs) were used for the comparative biomechanical testing. RESULTS: The statistical analysis of the stiffness of the fixation developed a significant difference in favor of the plate in all test directions. CONCLUSIONS: The excellent biomechanical results are very promising and we hope for a reduction of the pseudarthrosis rate and shorten the postoperative treatment phase.


Subject(s)
Ankle Joint/surgery , Arthrodesis/methods , Bone Plates , Bone Screws , Joint Diseases/surgery , Postoperative Care/methods , Aged , Aged, 80 and over , Ankle Joint/physiopathology , Biomechanical Phenomena , Cadaver , Female , Humans , Joint Diseases/physiopathology , Male , Middle Aged , Radiography
6.
Int J Obes (Lond) ; 41(10): 1503-1509, 2017 10.
Article in English | MEDLINE | ID: mdl-28566749

ABSTRACT

OBJECTIVE: To assess longitudinal associations between screen-based media use (television (TV) and computer hours, having a TV in the bedroom) and body fatness among UK children. METHODS: Participants were 12 556 children from the UK Millennium Cohort Study who were followed from age 7 to age 11 years. Associations were assessed between screen-based media use and the following outcomes: body mass index (BMI), fat mass index (FMI), and overweight. RESULTS: In fully adjusted models, having a bedroom TV at age 7 years was associated with significantly higher BMI and FMI (excess BMI for boys=0.29, 95% confidence interval (CI) 0.06-0.52; excess BMI for girls=0.57, 95% CI 0.31-0.84; excess FMI for boys=0.20, 95% CI 0.04-0.37; excess FMI for girls=0.39, 95% CI 0.21-0.57) and increased risk of being overweight (relative risk (RR) for boys=1.21, 95% CI 1.07-1.36; RR for girls=1.31, 95% CI 1.15-1.48) at age 11 years, compared with having no bedroom TV. Hours spent watching TV or digital versatile disks were associated with increased risk of overweight among girls only. Computer use at age 7 years was not related to later body fatness for either gender. CONCLUSION: Having a TV in the child's bedroom was an independent risk factor for overweight and increased body fatness in this nationally representative sample of UK children. Childhood obesity prevention strategies should consider TVs in children's bedrooms as a risk factor for obesity.


Subject(s)
Pediatric Obesity/epidemiology , Sedentary Behavior , Television/statistics & numerical data , Body Mass Index , Child , Child Behavior/psychology , Computers/statistics & numerical data , Feeding Behavior , Female , Humans , Longitudinal Studies , Male , Pediatric Obesity/physiopathology , Pediatric Obesity/psychology , Prospective Studies , Risk Factors , Sleep Deprivation/epidemiology , Sleep Deprivation/physiopathology , Social Environment , United Kingdom/epidemiology
7.
Opt Lett ; 42(10): 1887-1890, 2017 May 15.
Article in English | MEDLINE | ID: mdl-28504751

ABSTRACT

Coherent beam combining in the femtosecond regime of a record number of 19 fibers is demonstrated. The interferometric phase measurement technique, particularly well suited to phase-lock a very large number of fibers, is successfully demonstrated in the femtosecond regime. A servo loop is implemented to control piezoelectric fiber stretchers for both phase and delay variation compensation. The residual phase errors are below λ/60 rms. Nearly 50% of the total energy is contained in the far-field central lobe. After compression, we obtain a combined pulse width of 300 fs identical to the master oscillator pulse width.

9.
Benef Microbes ; 8(1): 121-131, 2017 Feb 07.
Article in English | MEDLINE | ID: mdl-27824277

ABSTRACT

Commensal skin microbiota plays an important role in both influencing the immune response of the skin and acting as a barrier against colonisation of potentially pathogenic microorganisms and overgrowth of opportunistic pathogens. Staphylococcus epidermidis is a key constituent of the normal microbiota on human skin. It balances the inflammatory response after skin injury and produces antimicrobial molecules that selectively inhibit skin pathogens. Here we describe Lactobacillus brevis DSM17250 that was identified among hundreds of Lactobacillus strains to exhibit an anti-inflammatory effect in human keratinocytes in vitro and specific stimulatory impact on the growth of S. epidermidis. The aqueous cell-free extract of L. brevis DSM17250 was used in an ointment formulation and tested in a randomized placebo-controlled double blinded human pilot study. Healthy volunteers with diagnosed dry skin were treated for four weeks. The study data shows that L. brevis DSM17250 extract induces re-colonisation of the skin by protective commensal microorganisms as judged from selective bacterial cultivation of surface-associated skin microorganism of the lower leg. Furthermore, the 4 week administration of the L. brevis DSM17250 extract significantly improved the transepidermal water loss value (TEWL), reduced the xerosis cutis symptoms and stinging. The data shows that daily application of L. brevis DSM17250 extract in a topical product significantly improves the microbial skin microbiota by promoting the growth of species which possess beneficial regulatory and protective properties such as S. epidermidis. Restoring the natural skin microbiota leads to significantly improved skin barrier function (as transepidermal water loss) and decrease of xeroderma (xerosis cutis) symptoms (as measured by dry skin area and severity index, DASI). We propose that improving and stabilizing the natural skin microbiota by specifically stimulating the growth of S. epidermidis is an important and novel concept to manage skin diseases associated with microbiota dysbiosis.


Subject(s)
Anti-Inflammatory Agents/administration & dosage , Levilactobacillus brevis/chemistry , Microbiota , Ointments/administration & dosage , Skin Diseases/prevention & control , Staphylococcus epidermidis/growth & development , Adult , Double-Blind Method , Female , Humans , Male , Middle Aged , Pilot Projects , Placebos , Skin/microbiology , Skin Diseases/microbiology , Treatment Outcome
10.
Tissue Eng Regen Med ; 14(6): 803-814, 2017 Dec.
Article in English | MEDLINE | ID: mdl-30603529

ABSTRACT

Autologous disc cell transplantation (ADCT) is a cell-based therapy aiming to initiate regeneration of intervertebral disc (IVD) tissue, but little is known about potential risks. This study aims to investigate the presence of structural phenomena accompanying the transformation process after ADCT treatment in IVD disease. Structural phenomena of ADCT-treated patients (Group 1, n = 10) with recurrent disc herniation were compared to conventionally-treated patients with recurrent herniation (Group 2, n = 10) and patients with a first-time herniation (Group 3, n = 10). For ethical reasons, a control group of ADCT patients who did not have a recurrent disc herniation was not possible. Tissue samples were obtained via micro-sequestrectomy after disc herniation and analyzed by micro-computed tomography, scanning electron microscopy, energy dispersive spectroscopy, and histology in terms of calcification zones, tissue structure, cell density, cell morphology, and elemental composition. The major differentiator between sample groups was calcium microcrystal formation in all ADCT samples, not found in any of the control group samples, which may indicate disc degradation. The incorporation of mineral particles provided clear contrast between the different materials and chemical analysis of a single particle indicated the presence of magnesium-containing calcium phosphate. As IVD calcification is a primary indicator of disc degeneration, further investigation of ADCT and detailed investigations assessing each patient's Pfirrmann degeneration grade following herniation is warranted. Structural phenomena unique to ADCT herniation prompt further investigation of the therapy's mechanisms and its effect on IVD tissue. However, the impossibility of a perfect control group limits the generalizable interpretation of the results.

12.
Gesundheitswesen ; 78(10): 672-677, 2016 Oct.
Article in German | MEDLINE | ID: mdl-26335657

ABSTRACT

Worldwide, non-communicable diseases including dental caries and periodontal diseases, remain a major public health problem. Moreover, there is a social gradient in health across society that runs from the top to the bottom in a linear, stepwise fashion. Health promoting behaviours become more difficult to sustain further down the social ladder. Oral health inequalities also exist in Germany. Earlier explanations of social inequalities have mainly focused on individual lifestyle factors, ignoring the broader social determinants of health and disease. Until recently, the dominant approaches to general health promotion focused on actions to reduce specific diseases, separating oral health from general health. An alternative approach is the common risk factor approach (CRFA) where risk factors common to a number of major chronic diseases, including diseases of the mouth and teeth, are tackled. The CRFA focuses on the common underlying determinants of health to improve the overall health of populations, thereby reducing social inequalities. The main implication of the CRFA for oral health policies is to work in partnership with a range of other sectors and disciplines. Oral health issues need to be integrated with recommendations to promote general health. Improvements in oral health and a reduction in oral health inequalities are more likely by working in partnership across sectors and disciplines using strategies that focus upstream on the underlying determinants of oral diseases.


Subject(s)
Delivery of Health Care, Integrated/organization & administration , Delivery of Health Care/organization & administration , Health Promotion/organization & administration , Healthcare Disparities/organization & administration , Oral Health/statistics & numerical data , Risk Assessment/methods , Clinical Decision-Making/methods , Dental Care/organization & administration , Evidence-Based Medicine , Germany , Health Care Rationing/organization & administration , Health Policy , Humans , Models, Organizational , Public Health , Socioeconomic Factors , Stomatognathic Diseases/prevention & control
14.
Eur Cell Mater ; 29: 22-34, 2015 Jan 02.
Article in English | MEDLINE | ID: mdl-25552426

ABSTRACT

Mesenchymal stem cells (MSC) were shown to support bone regeneration, when they were locally transplanted into poorly healing fractures. The benefit of systemic MSC transplantation is currently less evident. There is consensus that systemically applied MSC are recruited to the site of injury, but it is debated whether they actually support bone formation. Furthermore, the question arises as to whether circulating MSC are recruited only in case of injury or whether they also participate in mechanically induced bone formation. To answer these questions we injected green fluorescent protein (GFP)-labelled MSC into C57BL/6J mice, which were subjected either to a femur osteotomy or to non-invasive mechanical ulna loading to induce bone formation. We detected GFP-labelled MSC in the early (day 10) and late fracture callus (day 21) by immunohistochemistry. Stromal cell-derived factor 1 (SDF-1 or CXCL-12), a key chemokine for stem cell attraction, was strongly expressed by virtually all cells near the osteotomy--indicating that SDF-1 may mediate cell migration to the site of injury. We found no differences in SDF-1 expression between the groups. Micro-computed tomography (µCT) revealed significantly more bone in the callus of the MSC treated mice compared to untreated controls. The bending stiffness of callus was not significantly altered after MSC-application. In contrast, we failed to detect GFP-labelled MSC in the ulna after non-invasive mechanical loading. Histomorphometry and µCT revealed a significant load-induced increase in bone formation; however, no further increase was found after MSC administration. Concluding, our results suggest that systemically administered MSC are recruited and support bone formation only in case of injury but not in mechanically induced bone formation.


Subject(s)
Fracture Healing , Fractures, Bone/therapy , Mesenchymal Stem Cell Transplantation/methods , Mesenchymal Stem Cells/cytology , Osteogenesis , Animals , Bone Regeneration , Bony Callus/metabolism , Bony Callus/physiopathology , Cells, Cultured , Chemokine CXCL12/metabolism , Fractures, Bone/metabolism , Fractures, Bone/physiopathology , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/metabolism , Immunohistochemistry , Male , Mesenchymal Stem Cells/metabolism , Mice, Inbred C57BL , Mice, Transgenic , Time Factors , X-Ray Microtomography
15.
Hamostaseologie ; 34 Suppl 1: S53-6, 2014.
Article in English | MEDLINE | ID: mdl-25382772

ABSTRACT

The manifestation of an unclear bleeding tendency in childhood calls for an extended coagulation work-up, particularly when a battered child syndrome is suspected and typical concomitant injuries are absent. The chosen diagnostic tests should be able to detect the presence of relatively common coagulation defects such as von Willebrand syndrome or hemophilia, but also rare diseases such as inherited thrombocytopathies. The PFA-100® test does not help to provide a definite diagnosis especially in cases of mild inherited thrombocytopathies, since in most cases the PFA-100® test results are normal. For this purpose, specific platelet function testing is needed. However, the methods are only available in some coagulation laboratories. Also, other limitations need to be taken into consideration such as pre-analytical problems and difficulties in the interpretation of test results especially in infants. We present two cases that were diagnosed with an aspirin-like defect as an inherited thrombocytopathy, even though their PFA-100 closure times were within the normal range. Based on pathological findings in the platelet aggregometry test, this diagnosis could be made.


Subject(s)
Battered Child Syndrome/blood , Battered Child Syndrome/diagnosis , Hemorrhage/blood , Hemorrhage/diagnosis , Platelet Function Tests/methods , Child , Diagnosis, Differential , Female , Forensic Medicine/methods , Humans , Infant , Male
16.
Acta Biomater ; 9(1): 4845-55, 2013 Jan.
Article in English | MEDLINE | ID: mdl-22885682

ABSTRACT

This work investigated the suitability of microporous ß-tricalcium phosphate (TCP) scaffolds pre-seeded with autologous chondrocytes for treatment of osteochondral defects in a large animal model. Microporous ß-TCP cylinders (Ø 7 mm; length 25 mm) were seeded with autologous chondrocytes and cultured for 4 weeks in vitro. Only the upper end of the cylinder was seeded with chondrocytes. Chondrocytes formed a multilayer on the top. The implants were then implanted in defects (diameter 7 mm) created in the left medial femoral condyle of ovine knees. The implants were covered with synovial membrane from the superior recess of the same joint. For the right knees, an empty defect with the same dimensions served as control. Twenty-eight sheep were split into 6-, 12-, 26- and 52 week groups of seven animals. Indentation tests with a spherical (Ø 3mm) indenter were used to determine the biomechanical properties of regenerated tissue. A software-based limit switch was implemented to ensure a maximal penetration depth of 200 µm and maximal load of 1.5 N. The achieved load, the absorbed energy and the contact stiffness were measured. Newly formed cartilage was assessed with the International Cartilage Repair Society Visual Assessment Scale (ICRS score) and histomorphometric analysis. Results were analysed statistically using the t-test, Mann-Whitney U-test and Wilcoxon test. Statistical significance was set at p<0.05. After 6 weeks of implantation, the transplanted area tolerated an indentation load of 0.05±0.20 N. This value increased to 0.10±0.06 N after 12 weeks, to 0.27±0.18 N after 26 weeks, and 0.27±0.11 N after 52 weeks. The increase in the tolerated load was highly significant (p<0.0001), but the final value was not significantly different from that of intact cartilage (0.30±0.12 N). Similarly, the increase in contact stiffness from 0.87±0.29 N mm-(1) after 6 weeks to 3.14±0.86 N mm(-1) after 52 weeks was highly significant (p<0.0001). The absorbed energy increased significantly (p=0.02) from 0.74×10(-6)±0.38×10(-6) Nm after 6 weeks to 2.83×10(-6)±1.35×10(-6) Nm after 52 weeks. At 52 weeks, the International Cartilage Repair Society (ICRS) scores for the central area of the transplanted area and untreated defects were comparable. In contrast, the score for the area from the edge to the centre of the transplanted area was significantly higher (p=0.001) than the score for the unfilled defects. A biomechanically stable cartilage was built outside the centre of defect. After 52 weeks, all but one empty control defect were covered by bone and a very thin layer of cartilage (ICRS 7 points). The empty hole could still be demonstrated beneath the bone. The histomorphometric evaluation revealed that 81.0±10.6% of TCP was resorbed after 52 weeks. The increase in TCP resorption and replacement by spongy bone during the observation period was highly significant (p<0.0001). In this sheep trial, the mechanical properties of microporous TCP scaffolds seeded with transplanted autologous chondrocytes were similar to those of natural cartilage after 52 weeks of implantation. However, the central area of the implants had a lower ICRS score than healthy cartilage. Microporous TCP was almost fully resorbed at 52 weeks and replaced by bone.


Subject(s)
Bone and Bones , Calcium Phosphates , Cartilage , Ceramics , Tissue Engineering , Tissue Scaffolds , Animals , Biomechanical Phenomena , Sheep
17.
Klin Padiatr ; 224(4): e1-e10, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22782443

ABSTRACT

OBJECTIVE: Evaluation of lung function parameters and additional use of prostaglandin E1 (PGE1) for the stabilisation of cardiopulmonary function in patients with congenital diaphragmatic hernia (CDH) and pulmonary hypertension (PHT). DESIGN: Observational study. PATIENTS: Between 2007 and 2009 8 patients with CDH have been treated in our pediatric intensive care unit (gestational age 34 + 0 - 40 + 4 weeks, birth weight 2 160-3 840 g). All patients required respiratory support. Gentle mechanical ventilation adapted to the degree of pulmonary hypoplasia based on serially measurements of lung function parameters to find appropriate ventilator settings has been performed. MAIN RESULTS: Functional residual capacity (FRC) and compliance of the respiratory system in all patients were markedly reduced. A FRC between 9.3-10.6 ml/kg and compliance between 1.1-1.8 ml/kPa/kg indicated pronounced hypoplasia of the lungs. Doppler flow patterns through the arterial duct were classified into left-to-right, right-to-left and bidirectional shunting and correlated to the degree of PHT. The additional use of PGE1 to reopen the arterial duct and to stabilize right ventricular function led to an amelioration of severe PHT and preoperative stabilisation in 2 newborns with pronounced pulmonary hypoplasia. All patients underwent successful surgery, and did not show any complications after 2 years follow-up. CONCLUSION: Measurements of lung function parameters and adaptation of mechanical ventilation to the degree of pulmonary hypoplasia and additional therapy with PGE1 may help to improve the outcome in CDH patients.


Subject(s)
Abnormalities, Multiple/physiopathology , Abnormalities, Multiple/therapy , Alprostadil/administration & dosage , Heart Failure/physiopathology , Heart Failure/therapy , Hernias, Diaphragmatic, Congenital , Hypertension, Pulmonary/physiopathology , Hypertension, Pulmonary/therapy , Infant, Premature, Diseases/physiopathology , Infant, Premature, Diseases/therapy , Lung Diseases/physiopathology , Lung Diseases/therapy , Respiration, Artificial , Respiratory Function Tests , Ventricular Dysfunction, Right/physiopathology , Ventricular Dysfunction, Right/therapy , Algorithms , Combined Modality Therapy , Ductus Arteriosus, Patent/physiopathology , Ductus Arteriosus, Patent/therapy , Echocardiography, Doppler , Functional Residual Capacity/physiology , Hemodynamics/physiology , Hernia, Diaphragmatic/physiopathology , Hernia, Diaphragmatic/therapy , Humans , Infant, Newborn , Intensive Care Units, Neonatal , Lung/abnormalities , Lung/physiopathology , Oxygen/blood
18.
J Mater Sci Mater Med ; 23(8): 1879-89, 2012 Aug.
Article in English | MEDLINE | ID: mdl-22689010

ABSTRACT

Wear particles from the bearing surfaces of joint implants are one of the main limiting factors for total implant longevity. Si(3)N(4) is a potential wear resistant alternative for total joint replacements. In this study, Si(x)N(y)-coatings were deposited on cobalt chromium-discs and Si-wafers by a physical vapour deposition process. The tribological properties, as well as surface appearance, chemical composition, phase composition, structure and hardness of these coatings were analysed. The coatings were found to be amorphous or nanocrystalline, with a hardness and coefficient of friction against Si(3)N(4) similar to that found for bulk Si(3)N(4). The low wear rate of the coatings indicates that they have a potential as bearing surfaces of joint replacements. The adhesion to the substrates remains to be improved.


Subject(s)
Chromium Alloys/chemistry , Coated Materials, Biocompatible/chemistry , Joint Prosthesis , Silicon Compounds/chemistry , Adhesiveness , Friction , Hardness , Lubrication , Materials Testing , Surface Properties
19.
Scanning ; 34(4): 221-9, 2012.
Article in English | MEDLINE | ID: mdl-22076793

ABSTRACT

We report the investigation of the interfaces between microneedle arrays and cell cultures in patch-on-chip systems by using Focused Ion Beam (FIB) preparation and Scanning Electron Microscopy (SEM). First, FIB preparations of micro chips are made to determine the size and shape of the designed microneedles. In this essay, we investigate the cell-substrate interaction, especially the cell adhesion, and the microneedle's potential cell penetration. For this purpose, cross-sectional preparation of these hard/soft hybrid structures is performed by the FIB technology. By applying the FIB technology followed by high-resolution imaging with SEM, new insights into the cell-substrate interface can be received. One can clearly distinguish between cells that are only in contact with microneedles and cells that are penetrated by microneedles. A stack of slice images is collected by the application of the slice-and-view setup during FIB preparation and is used for three-dimensional reconstruction of cells and micro-needles.


Subject(s)
Cell Adhesion , Fibroblasts/physiology , Microscopy, Electron, Scanning/methods , Specimen Handling/methods , Animals , Mice
20.
Biophys Chem ; 139(2-3): 99-105, 2009 Feb.
Article in English | MEDLINE | ID: mdl-19013001

ABSTRACT

Forisomes are chemomechanically active P-protein aggregates found in the phloem of legumes. They can convert chemical energy into mechanical work when induced by divalent metal ions or changes in pH, which control the folding state of individual forisome proteins. We investigated the changing geometric parameters of individual forisomes and the strength and dynamics of the forces generated during this process. Three different divalent ions were tested (Ca2+, Sr2+ and Ba2+) and were shown to induce similar changes to the normalized length and diameter. In the concentration range from 0.1 to 4 M, K+ and Cl(-) ions had no influence on the contraction behaviour of the forisomes induced by 10 mM Ca2+. In the absence of dissolved oxygen, these changes were independent of the radius of the metal ion, water uptake and the strength of binding between the selected metal ions and those protein molecules responsible for forisome conformational transformation. In the absence of any load, bound Ca2+, Sr2+ and Ba2+ ions showed apparent and averaged dissociation constants of 14, 62 and 1070 microM, respectively. Various forisomes generated bending on a quartz glass fibre with a diameter of 9 microm. The fibre bending was measured microscopically also by correlation between the digital patterns of a predefined window of observation before and after bending. Similar bending forces of approximately 90 nN were measured for a single forisome sequentially exposed to 10 mM Ca2+, Sr2+ and Ba2+. In the absence of dissolved oxygen, the same conditions resulted in averaged bending forces of (93+/-40) nN, (58+/-20) nN, and (91+/-20) nN after contacting different forisomes with 10 mM Ca2+, 10 mM Sr2+, and 10 mM Ba2+ respectively, demonstrating that the force generated was independent on ion concentrations above a certain threshold value.


Subject(s)
Plant Proteins/metabolism , Vicia faba/metabolism , Biomechanical Phenomena/drug effects , Hydrogen-Ion Concentration , Metals/metabolism , Metals/pharmacology , Protein Binding , Protein Conformation/drug effects
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