Nanostructured Conducting Polymers and Their Applications in Energy Storage Devices

Due to the energy requirements for various human activities, and the need for a substantial change in the energy matrix, it is important to research and design new materials that allow the availability of appropriate technologies. In this sense, together with proposals that advocate a reduction in the conversion, storage, and feeding of clean energies, such as fuel cells and electrochemical capacitors energy consumption, there is an approach that is based on the development of better applications for and batteries. An alternative to commonly used inorganic materials is conducting polymers (CP). Strategies based on the formation of composite materials and nanostructures allow outstanding performances in electrochemical energy storage devices such as those mentioned. Particularly, the nanostructuring of CP stands out because, in the last two decades, there has been an important evolution in the design of various types of nanostructures, with a strong focus on their synergistic combination with other types of materials. This bibliographic compilation reviews state of the art in this area, with a special focus on how nanostructured CP would contribute to the search for new materials for the development of energy storage devices, based mainly on the morphology they present and on their versatility to be combined with other materials, which allows notable improvements in aspects such as reduction in ionic diffusion trajectories and electronic transport, optimization of spaces for ion penetration, a greater number of electrochemically active sites and better stability in charge/discharge cycles.

TEAD and YAP regulate the enhancer network of human embryonic pancreatic progenitors

The genomic regulatory programmes that underlie human organogenesis are poorly understood. Pancreas development, in particular, has pivotal implications for pancreatic regeneration, cancer and diabetes. We have now characterized the regulatory landscape of embryonic multipotent progenitor cells that give rise to all pancreatic epithelial lineages. Using human embryonic pancreas and embryonic-stem-cell-derived progenitors we identify stage-specific transcripts and associated enhancers, many of which are co-occupied by transcription factors that are essential for pancreas development. We further show that TEAD1, a Hippo signalling effector, is an integral component of the transcription factor combinatorial code of pancreatic progenitor enhancers. TEAD and its coactivator YAP activate key pancreatic signalling mediators and transcription factors, and regulate the expansion of pancreatic progenitors. This work therefore uncovers a central role for TEAD and YAP as signal-responsive regulators of multipotent pancreatic progenitors, and provides a resource for the study of embryonic development of the human pancreas.

A mobile insulator system to detect and disrupt cis-regulatory landscapes in vertebrates

In multicellular organisms, cis-regulation controls gene expression in space and time. Despite the essential implication of cis-regulation in the development and evolution of organisms and in human diseases, our knowledge about regulatory sequences largely derives from analyzing their activity individually and outside their genomic context. Indeed, the contribution of these sequences to the expression of their target genes in their genomic context is still largely unknown. Here we present a novel genetic screen designed to visualize and interrupt gene regulatory landscapes in vertebrates. In this screen, based on the random insertion of an engineered Tol2 transposon carrying a strong insulator separating two fluorescent reporter genes, we isolated hundreds of zebrafish lines containing insertions that disrupt the cis-regulation of tissue-specific expressed genes. We therefore provide a new easy-to-handle tool that will help to disrupt and chart the regulatory activity spread through the vast noncoding regions of the vertebrate genome.

Bone mineral density in asthmatic patients treated with inhaled corticosteroids: a case-control study

Recent studies suggest that inhaled corticosteroids can adversely affect bone metabolism. The objective of this study was to evaluate the importance of these adverse effects in a case-control study. Bone mineral density (BMD) was measured in 48 asthmatic adults (15 males and 33 females) treated with inhaled steroids (beclomethasone or budesonide) and in 48 gender and age-matched healthy subjects at baseline and at 2 yrs. Vertebral BMD was measured by dual energy X-ray densitometry. Patients had been treated with a dose of 662 +/- 278 micrograms (range 300-1,000 micrograms) of beclomethasone dipropionate or budesonide for more than 1 yr (mean duration of treatment 10.6 yrs, range 1-16 yrs). Twenty four patients had needed 1-6 short courses of oral steroids and seven had received oral corticosteroids (mean daily dose 6.2 mg prednisone) for 2-15 yrs more than 4 yrs prior to the BMD measurements. During the follow-up, 14 patients required 1-3 short courses of oral steroids. There was no correlation either between inhaled corticosteroid doses or duration of treatment and BMD values. There were no significant differences in BMD baseline values between patients and healthy controls. BMD significantly decreased in both groups at 2 yrs, from 1.08 +/- 0.19 to 1.05 +/- 0.19 g.cm-2 (p = 0.002) in asthmatics versus 1.12 +/- 0.17 to 1.09 +/- 0.18 g.cm-2 (p = 0.008) in controls. There were no significant differences in BMD loss between patients and healthy controls. Furthermore, no differences were found in bone loss when pre- and postmenopausal women were compared with their healthy control counterparts. No differences in baseline BMD were found between patients who had received regular oral corticosteroid therapy or booster courses of oral corticosteroids and those who had not. Inhaled corticosteroid treatment at a mean dose of 662 micrograms.day-1 and sporadic booster courses of oral corticosteroids do not further increase bone mass loss with respect to that expected from natural bone mass loss.

Corticosteroid-induced bone loss. Prevention and management

Osteoporosis is one of the most serious adverse effects experienced by patients receiving long term corticosteroid therapy. Bone loss occurs soon after corticosteroid therapy is initiated and results from a complex mechanism involving osteoblastic suppression and increased bone resorption. There are a number of factors that may increase the risk of corticosteroid-induced osteoporosis [smoking, excessive alcohol (ethanol) consumption, amenorrhoea, relative immobilisation, chronic obstructive pulmonary disease, inflammatory bowel disease, hypogonadism in men, organ transplantation]. The initial assessment of patients about to start taking corticosteroids should include measurement of spinal bone density, urinary calcium level and plasma calcifediol (25-hydroxycholecalciferol) level; serum testosterone levels should also be measured when hypogonadism is suspected. Many different drugs have been used to prevent osteoporosis in patients receiving long-term corticosteroid therapy, including thiazide diuretics, cholecalciferol (vitamin D) metabolites, bisphosphonates, calcitonin, fluoride, estrogens, anabolic steroids and progesterone. At present, however, published studies have failed to demonstrate a reduction in the rate of fracture using different preventive pharmacological therapies in patients being treated with corticosteroids on a continuous basis. Among the drugs studied, bisphosphonates (pamidronic acid and etidronic acid) and calcitonin appear to be effective in increasing bone density. Cholecalciferol preparations have been reported to be effective in some, but not all, studies. Limited data have shown positive results with thiazide diuretics, estrogen, progesterone and nandrolone. When treating patients with corticosteroids, the lowest effective dose should be used, with topical corticosteroids used whenever possible. Auranofin may be considered in patients with corticosteroid-dependent asthma. Patients should take as much physical activity as possible, maintain an adequate daily intake of calcium (1000 mg/day0 and cholecalciferol (400 to 800 U/day), stop smoking and avoid excessive alcohol intake. It is important to detect and treat hypogonadism in men, if present, and to replace gonadal hormones in postmenopausal women or amenorrhoeic premenopausal women, and to detect and correct cholecalciferol deficiency. A thiazide diuretic should be considered if hypercalciuria is present (urinary calcium excretion in excess of 4 mg/kg/day). High-risk patients and those with established osteoporosis should be treated with bisphosphonates (cyclical etidronic acid or intravenous pamidronic acid), nasal calcitonin, or calcifediol or calcitriol. Patients receiving cholecalciferol preparations should be carefully monitored for hypercalciuria and hypecalcaemia.

Prevention of further bone mass loss by nasal calcitonin in patients on long term glucocorticoid therapy for asthma: a two year follow up study

BACKGROUND

Injectable calcitonin is effective in reducing spinal bone loss in steroid-dependent asthma but side effects are frequent. In contrast, a nasal spray presentation has been shown to be effective and well tolerated in involutional osteoporosis. To test the efficacy of nasal calcitonin a two year prospective trial was conducted in 44 steroid-dependent asthmatic patients.

METHODS

All patients received a calcium supplement of 1000 mg and were allocated randomly into two groups treated with either salmon calcitonin nasal spray (200 IU every other day, n = 22) or calcium alone (n = 22) for two years. All patients completed the first year of the study. Five patients in each group dropped out during the second year. In the calcitonin group one patient developed generalised pruritus and four lost steroid dependence, and in the calcium alone group five were no longer dependent on steroids. The efficacy of treatment was evaluated as follows: bone turnover assessed by biochemical markers, bone loss assessed by serial measurement of lumbar spine density, and rates of bone fractures.

RESULTS

The bone mass in the calcitonin group increased by 2.7% in the first year while in the group receiving calcium alone it decreased by 2.8%; this difference was significant. Calcitonin prevented more bone loss during the second year while the calcium alone group continued losing bone mass (-7.8%). The difference between means was 0.1077 (95% CI 0.0381 to 0.1773). Three new fractures occurred in both groups. No changes in biochemical parameters were detected in either group.

CONCLUSIONS

Calcitonin given intranasally increased spinal bone mass during the first year of treatment and maintained bone mass in a steady state during the second year. These results suggest that calcitonin may be a useful agent to prevent steroid-induced osteoporosis. However, the lack of effect of calcitonin on the rate of vertebral fractures does not permit its recommendation for routine use in preventing steroid-induced osteoporosis.

Vertebral fractures in steroid dependent asthma and involutional osteoporosis: a comparative study

BACKGROUND

Reduced bone mass predisposes patients to the development of vertebral fractures. Measurement of bone mass by non-invasive methods is used to detect patients with involutional osteoporosis at risk from fractures. These methods have not been assessed in patients with steroid dependent osteoporosis. The objective of this study was to assess the value of a predictive fracture threshold value of bone density in patients with steroid dependent asthma.

METHODS

Three groups of patients were studied. Group 1 (67 patients) had steroid dependent asthma (mean daily dose of prednisone 11.7 mg) and no vertebral fractures, group 2 (32 patients) had steroid dependent asthma (mean daily dose of prednisone 12 mg) and vertebral fractures, and group 3 (55 patients) were not taking steroids but had involutional osteoporosis and a recent non-traumatic vertebral fracture. Bone mineral density was measured by dual photon absorptiometry and vertebral fractures by radiography of the lumbar spine. A fracture threshold was determined in the two groups with fractures as the 90th percentile of the mean bone mineral density measured in the lumbar spine.

RESULTS

Bone mineral density was significantly higher in the steroid dependent group with fractures (group 2) than in group 3 patients, who had involutional osteoporosis and fractures (0.946 (0.18) g/cm2 v 0.830 (0.16) g/cm2). The fracture threshold value was therefore higher for patients with steroid related vertebral fractures (group 2, 1.173 g/cm2) than for those with involutional osteoporosis (group 3, 0.979 g/cm2). Vertebral fractures were more likely to occur in steroid dependent asthmatic patients with bone density above the fracture threshold value (obtained from subjects with involutional osteoporosis) than in subjects in group 3 (34% v 9%).

CONCLUSION

Vertebral fractures occur in patients treated with steroids in the presence of higher bone mineral density than is the case with patients with involutional osteoporosis. The findings suggests that the assessment of the efficacy of preventive treatment requires measurement of bone mineral density and radiology.

Intestinal calcium absorption and parathyroid hormone secretion in asthmatic patients on prolonged oral or inhaled steroid treatment

A secondary hyperparathyroidism resulting from decreased intestinal calcium (Ca) absorption has been proposed as a contributory factor to glucocorticoid-induced osteoporosis. Inhaled steroids do not usually suppress adrenal gland function unless daily doses above 1,500 microgram are used. A recent study, however, has shown a reduced total body calcium in patients on regular beclomethasone treatment. In theory, osteopenia in these patients could be due to a direct effect of inhaled steroids on bone or due to an impaired intestinal calcium absorption. In this study, Ca absorption and parathyroid hormone (PTH) secretion were evaluated in three groups: 1) asthmatics on continuous oral and inhaled steroid treatment (11.3 +/- 4.4, range 5-33.5 mg.day-1 prednisone and 660 +/- 265, range 400-1,600 microgram.day-1 beclomethasone, respectively); 2) asthmatics on regular beclomethasone therapy (585 +/- 210, range 400-1,200 microgram.day-1); and 3) healthy subjects. The prevalence of vertebral fractures was evaluated by a spinal X-ray. No differences were found in either Ca absorption or PTH serum levels between asthmatics and healthy subjects (analysis of variance-ANOVA). Vertebral fractures were significantly more frequent in patients from group 1 (14 of 25) than in those from group 2 (2 or 25). We conclude that both prolonged oral steroid treatment and inhaled steroids, at doses lower than 1,600 microgram.day-1 do not cause Ca malabsorption, and that hyperparathyroidism does not contribute to osteoporosis in these patients.

Intestinal calcium absorption and parathyroid hormone secretion in asthmatic patients on prolonged oral or inhaled steroid treatment

A secondary hyperparathyroidism resulting from decreased intestinal calcium (Ca) absorption has been proposed as a contributory factor to glucocorticoid-induced osteoporosis. Inhaled steroids do not usually suppress adrenal gland function unless daily doses above 1,500 microgram are used. A recent study, however, has shown a reduced total body calcium in patients on regular beclomethasone treatment. In theory, osteopenia in these patients could be due to a direct effect of inhaled steroids on bone or due to an impaired intestinal calcium absorption. In this study, Ca absorption and parathyroid hormone (PTH) secretion were evaluated in three groups: 1) asthmatics on continuous oral and inhaled steroid treatment (11.3 +/- 4.4, range 5-33.5 mg.day-1 prednisone and 660 +/- 265, range 400-1,600 microgram.day-1 beclomethasone, respectively); 2) asthmatics on regular beclomethasone therapy (585 +/- 210, range 400-1,200 microgram.day-1); and 3) healthy subjects. The prevalence of vertebral fractures was evaluated by a spinal X-ray. No differences were found in either Ca absorption or PTH serum levels between asthmatics and healthy subjects (analysis of variance-ANOVA). Vertebral fractures were significantly more frequent in patients from group 1 (14 of 25) than in those from group 2 (2 or 25). We conclude that both prolonged oral steroid treatment and inhaled steroids, at doses lower than 1,600 microgram.day-1 do not cause Ca malabsorption, and that hyperparathyroidism does not contribute to osteoporosis in these patients.

Treatment of steroid-induced osteopenia with calcitonin in corticosteroid-dependent asthma. A one-year follow-up study

Sixty-two steroid-dependent asthmatics who had not received any form of treatment to prevent bone loss were studied during a 12-month period. Patients were randomly divided into two groups. Thirty-one patients were treated with 1 g of elemental calcium taken daily plus 100 IU of salmon calcitonin every other day, administered subcutaneously; the remaining 31 patients received only calcium supplementation. In the calcitonin group, 11 patients dropped out of the study because of severe side effects (seven patients), lack of compliance (three patients), and exacerbation of asthma (one patient). The 20 patients who completed the 12-month follow-up period were analyzed and compared with 20 sex-matched patients from the control group. At one year, bone mineral density (BMD) had increased in the calcitonin group by a mean of 4% (p less than or equal to 0.001), whereas in the control group BMD had decreased by 2.5% (p less than or equal to 0.05). Parameters of bone remodeling (alkaline phosphatase and osteocalcin) decreased significantly in the calcitonin-treated group but not in the control group. Our findings show that calcitonin 100 IU, given three times/wk, is an effective drug in the treatment of steroid-induced osteopenia. Side effects, however, are frequent and cause a high degree of dropout from therapy. These findings suggest that further studies should be carried out with lower doses of calcitonin or by other better tolerated forms of delivery such as in a nasal spray.

Ability of asthmatics with and without respiratory arrest to detect added resistive loads

Asthmatics who sometimes experience respiratory arrest during an exacerbation are a particular concern. To date no adequate explanation exists for this phenomenon. Impaired perception of resistive loads is considered a factor in the development of hypercapnic respiratory failure, especially during exacerbation in patients with chronic obstructive pulmonary disease. We analyzed the perception of resistive loads in 10 asthmatics who had suffered two or more respiratory arrests during an acute exacerbation. A group of eight asthmatics (same mean age and basal bronchial obstruction) who had never developed respiratory arrest or acidosis during their exacerbations was also studied. No statistically significant differences were found between the two groups in the perception of resistive loads. This negative result seems to exclude a deficiency in the ability to detect resistive loads as a cause of respiratory arrest in asthmatic patients.

Coronary insufficiency in children. Coronary arteriographic studies in two siblings from a family with hyperbetalipoproteinemia

A family affected with hyperbetalipoproteinemia was studied. Two siblings, a boy 11 and a girl 9 years of age, with characteristic findings of homozygous type II hyperlipoproteinemia are described. The highly atherogenetic nature of this disorder is illustrated by the occurrence of progressive coronary atheromatosis in the boy, in whom two coronary arteriographic studies documented the development of progressive obstruction of two coronary arteries in the course of 2 years. During this interval angina pectoris developed followed by myocardial infarction, cardiomegaly and congestive heart failure. The sister has remained asymptomatic, with apparently normal coronary arteries at age 9 years. Phonocardiograms were suggestive of aortic valve involvement although no aortic valve gradient was demonstrated by cardiac catheterization.