20 research outputs found
of the Boston Keratopros-thesis
Purpose: We tested the feasibility of using titanium to enhance adhesion of the Boston Keratoprosthesis (B-KPro), ultimately to decrease the risk of implant-associated complications. Methods: Cylindrical rods were made of poly(methyl methacrylate) (PMMA), PMMA coated with titanium dioxide (TiO 2 ) over a layer of polydopamine (PMMA TiO2 ), smooth (Ti) and sandblasted (Ti SB ) titanium, and titanium treated with oxygen plasma (Ti ox and Ti SBox ). Topography and surface chemistry were analyzed by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). Adhesion force between rods and porcine corneas was measured ex vivo. Titanium sleeves, smooth and sandblasted, were inserted around the stem of the B-KPro and implanted in rabbits. Tissue adhesion to the stem was assessed and compared to an unmodified B-Kpro after 1 month. Results: X-ray photoelectron spectroscopy demonstrated successful deposition of TiO 2 on polydopamine-coated PMMA. Oxygen plasma treatment did not change the XPS spectra of titanium rods (Ti and Ti SB ), although it increased their hydrophilicity. The materials did not show cell toxicity. After 14 days of incubation, PMMA TiO2 , smooth titanium treated with oxygen plasma (Ti ox ), and sandblasted titanium rods (Ti SB , Ti SBox ) showed significantly higher adhesion forces than PMMA ex vivo. In vivo
Opposing Roles for Membrane Bound and Soluble Fas Ligand in Glaucoma-Associated Retinal Ganglion Cell Death
Glaucoma, the most frequent optic neuropathy, is a leading cause of blindness worldwide. Death of retinal ganglion cells (RGCs) occurs in all forms of glaucoma and accounts for the loss of vision, however the molecular mechanisms that cause RGC loss remain unclear. The pro-apoptotic molecule, Fas ligand, is a transmembrane protein that can be cleaved from the cell surface by metalloproteinases to release a soluble protein with antagonistic activity. Previous studies documented that constitutive ocular expression of FasL maintained immune privilege and prevented neoangeogenesis. We now show that FasL also plays a major role in retinal neurotoxicity. Importantly, in both TNFα triggered RGC death and a spontaneous model of glaucoma, gene-targeted mice that express only full-length FasL exhibit accelerated RGC death. By contrast, FasL-deficiency, or administration of soluble FasL, protected RGCs from cell death. These data identify membrane-bound FasL as a critical effector molecule and potential therapeutic target in glaucoma
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Keratoprosthesis: A Review of Recent Advances in the Field
Since its discovery in the years of the French Revolution, the field of keratoprostheses has evolved significantly. However, the path towards its present state has not always been an easy one. Initially discarded for its devastating complications, the introduction of new materials and the discovery of antibiotics in the last century gave new life to the field. Since then, the use of keratoprostheses for severe ocular surface disorders and corneal opacities has increased significantly, to the point that it has become a standard procedure for corneal specialists worldwide. Although the rate of complications has significantly been reduced, these can impede the long-term success, since some of them can be visually devastating. In an attempt to overcome these complications, researchers in the field have been recently working on improving the design of the currently available devices, by introducing the use of new materials that are more biocompatible with the eye. Here we present an update on the most recent research in the field
Alterations in Plasma Triglyceride Concentrations Following Two Oral Meals with Different Fat Content in Patients with Type 2 Diabetes Mellitus
Background: Enhanced postprandial lipaemia has been reported in patients
with obesity, hypertension, metabolic syndrome and type 2 diabetes
mellitus (T2DM). We compared 2 oral fat meal tests (LIPOLD: 149g of fat,
56g of carbohydrates and 11.7g of proteins administrated per 2m(2) of
body surface) and LIPOTEST: 75g of fat, 25g of carbohydrates and 10g of
protein with the addition of 15g common sugar) with regard to changes in
triglycerides (TGs) as well as other cardiometabolic parameters between
baseline and 4 h after the meals.
Methods: We studied 21 men [median age (interquartile range; IQR) = 65
(16) years] with well-controlled T2DM [median glycated haemoglobin
(HbA1c) (IQR) = 6.6 (0.9) %]. All participants performed the meals with
1 week interval between the 2 meals.
Results: Median (IQR) TG differences in mg/dl were 86 (100) and 46 (60)
for LIPOLD and LIPOTEST meals, respectively, whereas the % differences
in TGs were 105 (105) and 48 (55), respectively. The differences (in
mg/dl and %) between TGs before ingesting the test meal and after 4h
were significant for both LIPOLD and LIPOTEST meals (p = 0.003 for mg/dl
differences and p = 0.005 for % differences). Patients who had a
positive response to the LIPOLD meal (i.e. TGs > 220 mg/dl at 4 h) also
had increased postprandial TGs with LIPOTEST. The Homeostasis Model
Assessment of Insulin Resistance (HOMA-IR) correlated with TG
differences (in mg/dl) following the LIPOLD meal consumption (Spearman’s
rho = (+) 0.527, p = 0.02). C-peptide correlated with TG differences (in
mg/dl) following the LIPOTEST meal consumption (Spearman’s rho = (+)
0.538, p = 0.032). There were no differences in TGs and glucose response
postprandially in both testing meals according to body mass index
(except for TGs between tertile 21.3-24.5 and 25-26.8 kg/m(2), p=0.046,
in LPOTEST group) and body surface area.
Conclusion: An oral fat tolerance test (OFTT), which contains 75g fat,
and represents the everyday habits of Western societies, could provide
additional information regarding the postprandial state of the
individuals with well-controlled T2DM. The consumption of meals with
very high fat content may lead to over diagnosing PPL. TG differences
after the consumption of a high fat meal correlated with HOMA-IR. This
may be useful to evaluate the role of HOMA-IR in T2DM patients. A
standardized the OFTT will help clinicians to better define postprandial
TG abnormalities, leading to more appropriate therapeutic options to
improve postprandial dysmetabolism
Immunogenicity of the Two mRNA SARS-CoV-2 Vaccines in a Large Cohort of Dialysis Patients
Chronic kidney disease patients, especially those on hemodialysis, are at the highest risk of a severe course and death from COVID-19. Moreover, they appear to have suboptimal response in both cellular and humoral immunity after vaccination. The present study investigated humoral and cellular response and safety after two doses of either of the two authorized mRNA vaccines in a cohort of 310 patients on maintenance dialysis. The antibody response rate was 94.5%, with a median (25th, 75th) antibody titer of 3478 (1236, 8141) AU/mL. Only mild adverse effects were observed. Only vaccine type was independently associated with immunogenicity. Α statistically significant difference in favor of mRNA1273 versus BNT162b2 vaccine was observed. Antibody positivity (100% vs. 94.3%, p < 0.001), median (25th, 75th) antibody levels: 9499 (6118, 20,780) AU/mL vs. 3269 (1220, 7807) AU/mL (p < 0.001). Among the 65 patients tested for T-cell response, 27 (41.5%) had a positive one with a median (25th, 75th) antibody titer of 6007 (3405, 12,068) AU/mL, while 38 with no T-cell response presented a lower median (25th, 75th) antibody titer of 1744 (850, 4176) AU/mL (p < 0.001). Both mRNA vaccines are safe for dialysis patients and can trigger humoral and cellular responses, although with lower titers than those that have been reported to healthy individuals
Titanium Coating of the Boston Keratoprosthesis
Purpose We tested the feasibility of using titanium to enhance adhesion of the Boston Keratoprosthesis (B-KPro), ultimately to decrease the risk of implant-associated complications. Methods: Cylindrical rods were made of poly(methyl methacrylate) (PMMA), PMMA coated with titanium dioxide (TiO2) over a layer of polydopamine (PMMATiO2), smooth (Ti) and sandblasted (TiSB) titanium, and titanium treated with oxygen plasma (Tiox and TiSBox). Topography and surface chemistry were analyzed by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). Adhesion force between rods and porcine corneas was measured ex vivo. Titanium sleeves, smooth and sandblasted, were inserted around the stem of the B-KPro and implanted in rabbits. Tissue adhesion to the stem was assessed and compared to an unmodified B-Kpro after 1 month. Results: X-ray photoelectron spectroscopy demonstrated successful deposition of TiO2 on polydopamine-coated PMMA. Oxygen plasma treatment did not change the XPS spectra of titanium rods (Ti and TiSB), although it increased their hydrophilicity. The materials did not show cell toxicity. After 14 days of incubation, PMMATiO2, smooth titanium treated with oxygen plasma (Tiox), and sandblasted titanium rods (TiSB, TiSBox) showed significantly higher adhesion forces than PMMA ex vivo. In vivo, the use of a TiSB sleeve around the stem of the B-KPro induced a significant increase in tissue adhesion compared to a Ti sleeve or bare PMMA. Conclusions: Sandblasted titanium sleeves greatly enhanced adherence of the B-KPro to the rabbit cornea. This approach may improve adhesion with the donor cornea in humans as well. Translational Relevance This approach may improve adhesion with donor corneas in humans
Cardiovascular Magnetic Resonance Detects Inflammatory Cardiomyopathy in Symptomatic Patients with Inflammatory Joint Diseases and a Normal Routine Workup
Background. Patients with inflammatory joint diseases (IJD) are more likely to develop cardiovascular disease compared with the general population. We hypothesized that cardiovascular magnetic resonance (CMR) could identify cardiac abnormalities in patients with IJD and atypical symptoms unexplained by routine clinical evaluation. Patients-Methods. A total of 51 consecutive patients with IJD (32 with rheumatoid arthritis, 10 with ankylosing spondylitis, and 9 with psoriatic arthritis) and normal clinical, electrocardiographic and echocardiographic workups, were referred for CMR evaluation due to atypical chest pain, shortness of breath, and/or palpitations. Their CMR findings were compared with those of 40 non-IJD controls who were referred for the same reason. All participants were examined using either a 1.5 T or 3.0 T CMR system. For T1/T2 mapping, comparisons were performed separately for each field strength. Results. Biventricular systolic function was similar between groups. In total, 25 (49%) patients with IJD vs. 0 (0%) controls had replacement-type myocardial fibrosis (p < 0.001). The T2 signal ratio, early/late gadolinium enhancement, and extracellular volume fraction were significantly higher in the IJD group. Native T1 mapping was significantly higher in patients with IJD independent of the MRI field strength (p < 0.001 for both). T2 mapping was significantly higher in patients with IJD compared with controls only in those examined using a 1.5 T MR system—52.0 (50.0, 55.0) vs. 37.0 (33.5, 39.5), p < 0.001. Conclusions. In patients with IJD and a mismatch between cardiac symptoms and routine non-invasive evaluation, CMR uniquely identified a significant proportion of patients with myocardial inflammation. A CMR examination should be considered in patients with IJD in similar clinical settings
Coronary microvascular disease: The “Meeting Point” of Cardiology, Rheumatology and Endocrinology
Background Exertional chest pain/dyspnea or chest pain at rest are the
main symptoms of coronary artery disease (CAD), which are traditionally
attributed to insufficiency of the epicardial coronary arteries.
However, 2/3 of women and 1/3 of men with angina and 10% of patients
with acute myocardial infarction have no evidence of epicardial coronary
artery stenosis in X-ray coronary angiography. In these cases, coronary
microvascular disease (CMD) is the main causative factor. Aims To
present the pathophysiology of CMD in Cardiology, Rheumatology and
Endocrinology. Materials-Methods The pathophysiology of CMD in
Cardiology, Rheumatology and Endocrinology was evaluated. It includes
impaired microvascular vasodilatation, which leads to inability of the
organism to deal with myocardial oxygen needs and, hence, development of
ischemic pain. CMD, observed in inflammatory autoimmune rheumatic and
endocrine/metabolic disorders, brings together Cardiology, Rheumatology
and Endocrinology. Causative factors include persistent systemic
inflammation and endocrine/metabolic abnormalities influencing directly
the coronary microvasculature. In the past, the evaluation of
microcirculation was feasible only with the use of invasive techniques,
such as coronary flow reserve assessment. Currently, the application of
advanced imaging modalities, such as cardiovascular magnetic resonance
(CMR), can evaluate CMD non-invasively and without ionizing radiation.
Results CMD may present with a variety of symptoms with 1/3 to 2/3 of
them expressed as typical chest pain in effort, more commonly found in
women during menopause than in men. Atypical presentation includes chest
pain at rest or exertional dyspnea,but post exercise symptoms are not
uncommon. The treatment with nitrates is less effective in CMD, because
their vasodilator action in coronary micro-circulation is less
pronounced than in the epicardial coronary arteries. Discussion Although
both classic and new medications have been used in the treatment of CMD,
there are still many questions regarding both the pathophysiology and
the treatment of this disorder. The potential effects of anti-rheumatic
and endocrine medications on the evolution of CMD need further
evaluation. Conclusion CMD is a multifactorial disease leading to
myocardial ischemia/fibrosis alone or in combination with epicardial
coronary artery disease. Endothelial dysfunction/vasospasm, systemic
inflammation, and/or neuroendocrine activation may act as causative
factors and bring Cardiology, Rheumatology and Endocrinology together.
Currently, the application of advanced imaging modalities, and
specifically CMR, allows reliable assessment of the extent and severity
of CMD. These measurements should not be limited to “pure cardiac
patients”, as it is known that CMD affects the majority of patients
with autoimmune rheumatic and endocrine/metabolic disorders