Dual second harmonic generation and up-conversion photoluminescence emission in highly-optimized LiNbO3 nanocrystals doped and co-doped with Er3+ and Yb3

Preparation from the aqueous alkoxide route of doped and co-doped lithium niobate nanocrystals with Er3+ and Yb3+ ions, and detailed investigations of their optical properties are presented in this comprehensive work. Simultaneous emission under femtosecond laser excitation of second harmonic generation (SHG) and up-conversion photoluminescence (UC-PL) is studied from colloidal suspensions according to the lanthanide ion contents. Special attention has been paid to produce phase pure nanocrystals of constant size (∼20 nm) thus allowing a straightforward comparison and optimization of the Er content for increasing the green UC-PL signals under 800 nm excitation. An optimal molar concentration at about 4 molar% in erbium ions is demonstrated, that is well above the concentration usually achieved in bulk crystals. Similarly, for co-doped LiNbO3 nanocrystals, different lanthanide concentrations and Yb/Er content ratios are tested allowing optimization of the green and red up-conversion excited at 980 nm, and analysis of the underlying mechanisms from excitation spectra. All together, these findings provide valuable insights into the wet-chemical synthesis and potential of doped and co-doped LiNbO3 nanocrystals for advanced applications, combining both SHG and UC-PL emissions from the particle core.

Drosophila CRISPR/Cas9 mutants as tools to analyse cardiac filamin function and pathogenicity of human FLNC variants

Filamins are large proteins with actin binding properties. Mutations in FLNC, one of the three filamin genes in humans, have recently been implicated in dominant cardiomyopathies, but the underlying mechanisms are not well understood. Here, we aimed to use Drosophila melanogaster as a new in vivo model to study these diseases. First, we show that adult-specific cardiac RNAi-induced depletion of Drosophila Filamin (dFil) induced cardiac dilatation, impaired systolic function and sarcomeric alterations, highlighting its requirement for cardiac function and maintenance of sarcomere integrity in the adult stage. Next, we introduced in the cheerio gene, using CRISPR/Cas9 gene editing, three missense variants, previously identified in patients with hypertrophic cardiomyopathy. Flies carrying these variants did not exhibit cardiac defects or increased propensity to form filamin aggregates, arguing against their pathogenicity. Finally, we show that deletions of the C-term part of dFil carrying the last four Ig-like domains are dispensable for cardiac function. Collectively, these results highlight the relevance of this model to explore the cardiac function of filamins and increase our understanding of physio-pathological mechanisms involved in FLNC-related cardiomyopathies.

Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

Metal Acetylacetonate–Bidentate Ligand Interaction (MABLI) as highly efficient free radical generating systems for polymer synthesis

Metal Acetylacetonate–Bidentate Ligand Interaction (MABLI) is presented here as a new chemical mechanism for the highly efficient generation of free radicals for polymer synthesis.

Folate-modified silicon carbide nanoparticles as multiphoton imaging nanoprobes for cancer-cell-specific labeling

SHG-active SiC nanoparticles were modified with folic acid for cancer-cell-specific labelling.

Brilliant molecular nanocrystals emerging from sol-gel thin films: towards a new generation of fluorescent biochips

To develop highly sensitive biosensors, we made directly available to biological aqueous solutions organic nanocrystals previously grown in the pores of sol-gel films. Through the controlled dissolution of the sol-gel surface, we obtained emerging nanocrystals that remained strongly anchored to the sol-gel coating for good mechanical stability of the final sensing device. We demonstrated that in the presence of a solution of DNA functionalized with a molecular probe, the nanocrystal fluorescence is strongly quenched by Förster resonance energy transfer thus opening the way towards very sensitive fluorescent biosensors through biomolecules grafted onto fluorescent nanocrystals. Finally, this controlled dissolution, involving weak concentrated NaOH solution, is a generic process that can be used for the thinning of any kind of sol-gel layer.

Determination of ethylenediaminetetraacetic acid at very low concentrations by high-performance liquid chromatography coupled with electrospray mass spectrometry

Ethylenediaminetetraacetic acid (EDTA) is a metal complexing agent which is commonly used for removing metallic surface contaminations. But its presence in aqueous industrial effluents or in wastes, by example those which are generated from nuclear power facilities, is forbidden or strictly regulated by the legislation. The implementation of high-performance liquid chromatography coupled with mass spectrometry (MS) via an electrospray interface has exhibited a powerful capacity in the measurement of this complexing agent, in the form of its iron complex. The complex is eluted through a reversed stationary phase under slightly acidic conditions and the detection is performed by mass spectrometry in the single ion monitoring mode. This technique has allowed us to reach a detection limit of about 1 microg/l in EDTA for only 20 microl injected without any previous preconcentration, and to solve some analytical interferences observed in the case of industrial effluents with other analytical techniques such as ion chromatography.

Exotic mice as models for aging research: polemic and prospectus

Most gerontological research using rodent models employs inbred strains, or F1 hybrids derived from them, rather than populations of genetically heterogeneous individuals. This study presents the argument that reliance on genetically homogeneous rodents, though sanctioned by tradition, may not be ideal for many sorts of investigations, and that use of heterogeneous mice and rats would allow researchers to reach robust conclusions that were less likely to reflect strain-specific idiosyncrasies. Segregating stocks, bred by backcross, F2 cross, or four-way cross procedures, would be an improvement over inbred and F1 stocks, providing inexpensive, arbitrarily large, and reproducible populations of genetically diverse test subjects. These stocks would not, however, recapture allelic variations that are likely to have been lost when wild-trapped mice and rats are selected inadvertently over dozens of generations for breeding success in laboratory conditions. Development of specific pathogen free stocks from wild-trapped progenitors particularly from populations selected for relevant evolutionary history and physiological characteristics, may be of great value for analysis of aging and late-life pathophysiology.

Suppressor of fused links fused and Cubitus interruptus on the hedgehog signalling pathway

The Hedgehog (Hh) family of signalling proteins [1] mediate inductive interactions either directly or by controlling the transcription of other secreted proteins through the action of Gli transcription factors, such as Cubitus interruptus (Ci) [2]. In Drosophila, the transcription of Hh targets requires the activation of the protein kinase Fused (Fu) and the inactivation of both Suppressor of fused (Su(fu)) and Costal-2 (Cos-2) [3]. Fu is required for Hh signalling in the embryo and in the wing imaginal disc and acts also as an antitumorigen in ovaries [4]. All fu- phenotypes are suppressed by the loss of function of Su(fu) [5]. Fu, Cos-2 and Ci are co-associated in vivo in large complexes that are bound to microtubules in a Hh-dependent manner [6,7]. Here we investigate the role of Su(fu) in the intracellular part of the Hh signalling pathway. Using the yeast two-hybrid method and an in vitro binding assay, we show that Su(fu), Ci and Fu can interact directly to form a trimolecular complex, with Su(fu) binding to both its partners simultaneously. Su(fu) and Ci also co-immunoprecipitate from embryo extracts. We propose that, in the absence of Hh signalling, Su(fu) inhibits Ci by binding to it and that, upon reception of the Hh signal, Fu is activated and counteracts Su(fu), leading to the activation of Ci.

Reliable determination of furosine in human serum and dialysate proteins by high-performance liquid chromatography

Furosine, formed by hydrolysis of 1-deoxy-fructosyl-lysine (fructose-lysine), is a product of the Amadori rearrangement of glucose and epsilon-NH2-lysine. Fructose-lysine can react further with tissue and circulating proteins to produce advanced glycation end-products (AGEs). Peritoneal dialysate used in the treatment of patients with end-stage renal failure contains high concentrations of glucose which may lead to intraperitoneal formation of AGEs. To quantitate the kinetics of formation and peritoneal clearance of glycated peritoneal dialysate proteins, we developed an effective approach to the measurement of furosine in clinical samples of serum and peritoneal dialysate.

[Secondary hyperparathyroidism in the elderly. Apropos of 200 assays of intact parathormone]

OBJECTIVES

To evaluate the frequency of high levels of intact parathormone in an elderly population of hospitalized patients and to determine whether there are any correlations with different factors involved in phosphocalcium metabolism, nutritional status and renal function.

METHODS

Intact parathormone was assayed in all patients admitted to a geriatric ward (n = 200). Other laboratory tests included serum phosphorus, calcium, total albumin, prealbumin, ionized calcium, creatinine with calculation of the clearance and in 50 patients radioimmunoassay for 25 hydroxyvitamin D.

RESULTS

Intact parathormone was abnormally high (> 65 pg/ml) in 40 patients. Mean levels increased significantly with age and reached 70.5 pg/ml in patients 90 years of age and over. No correlation was found between intact parathormone and total serum calcium, corrected serum calcium, albumin or prealbumin. Inversely there was a significant correlation with serum phosphorus and creatinine and creatinine clearance. Serum levels of 25 hydroxyvitamin D were abnormally low in 82% of the patients. There was a constant and significant decrease in intact parathormone level 15 days after calcium and calcifediol substitution therapy in 13 patients.

CONCLUSION

The frequency of hyperparathyroidism increases with age to affect nearly 1 out of 2 subjects over 90. It would be useful to determine a threshold level for elderly subjects with a major risk of bone fracture.

Lysyl oxidase and Maillard reaction-mediated crosslinks in aging and osteoarthritic rabbit cartilage

Alterations in the integrity of the extracellular matrix play an important role in osteoarthritis. Matrix crosslinks in articular cartilage of the knee were studied in partially meniscectomized rabbits to compare changes due to osteoarthritis with those occurring during aging. Pyridinoline, a lysyl oxidase-initiated crosslink, and pentosidine, a crosslink formed by the Maillard/glycation reaction, were assayed separately on reverse-phase high performance liquid chromatography. A significant increase in the percentage of insoluble collagen was observed in normal 12-month-old rabbits compared with the levels in 3-month-old animals, whereas osteoarthritis was associated with a shift toward more soluble fractions. Total pyridinoline content did not change with age or osteoarthritis. Total pentosidine, however, increased significantly with age but remained constant with osteoarthritis. Analysis of the distribution of crosslinks among solubility fractions indicated a significant shift of pyridinoline from the pepsin-released fraction to the insoluble fraction with osteoarthritis, but no changes were observed with age. Pentosidine distribution shifted toward the pepsin-released fraction in osteoarthritis, with a shift toward the insoluble fraction with age. Because of the low levels of pentosidine present, its precise location, whether collagenous or noncollagenous, remains unclear. However, since pentosidine represents a marker for the overall Maillard reaction, the results of our studies support a role for Maillard reaction products in the aging of extracellular matrix. The shift of pentosidine toward more soluble fractions suggests the presence of matrix degradation and repair in osteoarthritis.

[Non-enzymatic glycosylation of proteins. Complications of diabetes mellitus, aging and kidney failure]

Non-enzymatic protein glycosylation is the first stage of the reaction described by L.C. Maillard. When the reaction progresses beyond that stage the long half-life molecules are damaged by formation of intermolecular crosslinking. The recent discovery of pentosidine, a crosslink between lysine and arginine residues, has demonstrated that advanced Maillard reaction is accelerated in diabetic patients with severe complications. Moreover, high tissue and plasma levels of pentosidine have been found in uraemia. The formation of advanced Maillard end-products (AGE) in plasma proteins constitutes a source of cell stimulation which induces macrophages to secrete cytokines, interleukin-1 and tumoral necrosis factor. Similarly, endothelial cells are induced to increase the permeability and production of the procoagulant factor. These mechanisms are thought to play an important role in the pathogenesis of atherosclerosis, nephropathy and thromboembolic disorders of diabetes. The discovery of beneficial effects of amino-guanidine, an inhibitor of advanced Maillard reaction, in the prevention of experimental diabetic complications opens a new line of investigation and new hopes for diabetics.

Primary hyperparathyroidism in very old patients

OBJECTIVES

To evaluate the clinical presentation and biological features of primary hyperparathyroidism (pHPT) in very old subjects.

METHODS

Thirty patients aged 75 years or more, with pHPT were analyzed retrospectively. The diagnosis of pHPT was based on usual biological signs and was always confirmed by the finding of morphological abnormalities with parathyroid imaging or neck surgical exploration.

RESULTS

At initial examination, recent general symptoms and neuromuscular symptoms were observed in 87% and 83% of the cases, respectively. Neuropsychiatric manifestations were noted in 73% of the cases. Confusion and depression were the most frequent findings, observed in 30% and 27% of the cases, respectively. In one of two patients with dementia like state, the mental status improved dramatically after surgery of the parathyroid adenoma. Serum calcium levels were in the normal range in 13% of the cases and equal or below 110 mg/L in 47% of the cases. There was no correlation between serum calcium level and the severity of mental changes. Serum parathyroid hormone determinations were abnormal in 93% of the patients. Thirteen patients underwent surgery with biological improvement in all cases. An ultrasonically guided percutaneous ethanol injection of parathyroid adenoma was performed in 10 patients with a biological cure rate of 50%.

CONCLUSION

This study shows the major prevalence and potential severity of neuropsychiatric disorders in pHPT in very old patients. Because neuropsychiatric disturbances can respond favourably to surgical treatment, the clinician must systematically look for pHPT in elderly patients with cognitive impairment.

[Secondary hyperparathyroidism in hospitalized aged patients: apropos of 200 assays of intact parathyroid hormone]

Plasma intact parathyroid hormone (PTH) determinations were performed in 200 elderly patients admitted in a geriatric care unit. Abnormally high levels of PTH were observed in 40 subjects. There was a significant correlation between plasma ionized calcium determinations or creatinine clearance and PTH levels. Subjects with high PTH levels exhibited constantly reduced levels of 25 OH-D3. A calcium and vitamin D supplement, performed in 13 patients, was constantly followed by a decrease of the PTH level.

Immunohistochemical detection of advanced glycosylation end products in diabetic tissues using monoclonal antibody to pyrraline

Pyrraline is one of the major Maillard compounds resulting from the reaction of glucose with amino compounds at slightly acidic pH. For in vivo studies, monoclonal pyrraline antibodies were raised after immunization of Balb/c mice with keyhole limpet hemocyamin-caproyl pyrraline conjugate. Of 660 hybridoma clones from one donor, 260 produced an antibody to the free hapten, two of which named Pyr-A and Pyr-B also cross-reacted with L-lysyl pyrraline. Using Pyr-B antibody and an ELISA, a gradual increase in pyrraline immunoreactivity was observed in serum albumin incubated with glucose or 3-deoxyglucosone. Plasma pyrraline levels increased fourfold (P less than 0.001) in Sprague-Dawley rats upon induction of diabetes with streptozotocin and were twofold increased in randomly selected plasmas from diabetic humans. Highly specific pyrraline immunoreactivity was detected in sclerosed glomeruli from diabetic and old normal kidneys as well as in renal arteries with arteriolosclerosis and in perivascular and peritubular sclerosed extracellular matrix and basement membranes. The preferential localization of pyrraline immunoreactivity in the extracellular matrix strengthens the notion that the advanced glycosylation reaction may contribute to decreased turnover and thickening of the extracellular matrix in diabetes and aging.

Oral contraceptives and the risk of endometrial cancer

The relationship between the use of combination oral contraceptives (OCs) and the risk of endometrial cancer was assessed in a case-control study conducted in the Swiss Canton of Vaud between 1 January 1988 and 31 July 1990. Subjects included 122 women aged 75 or less with histologically confirmed endometrial cancer, and 309 control women in hospital for acute conditions unrelated to OC use. Overall, 14 percent of cases and 27 percent of controls had ever used OCs, corresponding to a multivariate relative risk (RR) of 0.5 (95 percent confidence interval [CI]: 0.3, 0.8). The risk of endometrial cancer was found to be related inversely to duration of OC use: RR = 1.0 for less than two years of OC use; 0.5 for two to five years; and 0.3 (95 percent CI: 0.1, 0.7) for more than five years. The protection appeared greater within 20 years since last use, and the RR rose to 0.8 after 20 or more years since last use; numbers are too small, however, for reliable inference from these subanalyses. No significant interaction or modifying effect was observed with other major factors related to endometrial cancer, including parity, body mass index, estrogen replacement therapy, and cigarette smoking. While this study provides further evidence for the protective effect of OCs against risk of endometrial cancer, the relationship requires continued evaluation to assess the long-term implications and public health impact of OC use.

[Determination of antibodies against nicotinic acetylcholine receptor: clinico-immunological correlations in 30 patients with myasthenia gravis]

In 30 patients with myasthenia gravis, serum assays were performed for antibodies to human nicotinic acetylcholine receptor. 19 of 20 generalized forms which were symptomatic and 6 of 9 patients in remission at the time of blood sample had detectable amounts of antibodies. The six highest levels were found in benign courses. 2 patients had a five- and twofold drop in antibody level during rapid deterioration. Patients in remission after thymectomy may still have low to moderate levels, while symptomatic patients occasionally have no detectable antibody.