Factors modulating fibrates response: therapeutic implications and alternative strategies

Peroxisome proliferator-activated receptor alpha (PPARalpha) regulates transcription of genes involved both in lipid and glucose metabolism as well as in inflammation. Fibrates are PPARalpha ligands used to normalize lipid and glucose parameters and exert antiinflammatory effects. In fact, fibrates have already been demonstrated to benefit metabolic syndrome, type 2 diabetes and cardiovascular diseases. This article reviews the mechanism of action and the functional roles of fibrates, emphasizing the factors modulating their capacity to activate PPARalpha and affecting their effectiveness. These factors may possibly explain the findings obtained in animal studies and clinical trials with fibrates which showed either untoward effects and/or inefficient hypolipidemic action of PPARalpha activation. We also discuss briefly the natural and synthetic agonists of PPARalphawhich are currently being developed and supposedly display greater effectiveness and fewer adverse effects than fibrates.

[Update of the topical treatment of psoriasis]

Topical therapy continues to be one of the pillars of psoriasis management. Topical corticosteroids and vitamin D analogs are the drugs of choice during the induction phase, and vitamin D analogs continue to be drugs of choice for maintenance therapy. Tazarotene and dithranol are suitable options in patients with certain, specific characteristics. The calcineurin inhibitors can be considered to be second-line treatment for psoriasis of the face and flexures. The efficacy and safety of the fixed-dose combination of betamethasone and calcipotriol in the induction phase is greater than that of either drug alone. The combination of corticosteroids with salicylic acid achieves better results than corticosteroids in monotherapy. None of the drugs evaluated stands out over the others in all clinical situations, and their use must therefore be individualized in each patient and adjusted according to the course of the disease.

Validation of simple indexes to assess insulin sensitivity during pregnancy in Wistar and Sprague-Dawley rats

Insulin resistance plays a role in the pathogenesis of diabetes, including gestational diabetes. The glucose clamp is considered the gold standard for determining in vivo insulin sensitivity, both in human and in animal models. However, the clamp is laborious, time consuming and, in animals, requires anesthesia and collection of multiple blood samples. In human studies, a number of simple indexes, derived from fasting glucose and insulin levels, have been obtained and validated against the glucose clamp. However, these indexes have not been validated in rats and their accuracy in predicting altered insulin sensitivity remains to be established. In the present study, we have evaluated whether indirect estimates based on fasting glucose and insulin levels are valid predictors of insulin sensitivity in nonpregnant and 20-day-pregnant Wistar and Sprague-Dawley rats. We have analyzed the homeostasis model assessment of insulin resistance (HOMA-IR), the quantitative insulin sensitivity check index (QUICKI), and the fasting glucose-to-insulin ratio (FGIR) by comparing them with the insulin sensitivity (SI(Clamp)) values obtained during the hyperinsulinemic-isoglycemic clamp. We have performed a calibration analysis to evaluate the ability of these indexes to accurately predict insulin sensitivity as determined by the reference glucose clamp. Finally, to assess the reliability of these indexes for the identification of animals with impaired insulin sensitivity, performance of the indexes was analyzed by receiver operating characteristic (ROC) curves in Wistar and Sprague-Dawley rats. We found that HOMA-IR, QUICKI, and FGIR correlated significantly with SI(Clamp), exhibited good sensitivity and specificity, accurately predicted SI(Clamp), and yielded lower insulin sensitivity in pregnant than in nonpregnant rats. Together, our data demonstrate that these indexes provide an easy and accurate measure of insulin sensitivity during pregnancy in the rat.

[Infliximab]

Infliximab is a chimeric monoclonal antibody, which specifically binds to tumor necrosis factor (TNF-alpha) and blocks its activity. Based on previous evidence that TNF-alpha has been involved in the pathogenesis of psoriasis, multiple controlled trials have shown that infliximab has provided a high degree of clinical benefit in the treatment of psoriasis and psoriatic arthritis allowing a major and rapid improvement in these patients. We review several clinical trials, which have firmly established both efficacy and safety of Infliximab in the treatment of moderate to severe psoriasis and psoriatic arthritis.

Pain management in adult acute sickle cell pain crisis: a viewpoint

BACKGROUND

The acute pain crisis of sickle cell disease is inadequately treated in many countries.

OBJECTIVE

To present a simple protocol that controls acute pain in most adult patients within 72 hours, based on our experience in an area where sickle cell disease is highly prevalent.

METHODS

Patients aged 14 years and above with sickle cell disease presenting with pain crisis are treated initially in the Emergency Room. Those responding adequately are discharged home on oral analgesics while those with persisting pain after 6 hours are treated further, for up to 72 hours, in an Observation Unit attached to the Emergency Room. Narcotic analgesics are administered regularly for the first 24 hours.

RESULTS

Using this protocol, acute pain crisis could be terminated or controlled in over 80% of patients within 72 hours.

CONCLUSION

Regular intravenous narcotic analgesia for the initial 24 hours, supplemented by oral analgesia, is useful for adult patients with severe acute sickle cell pain crisis when the pain is inadequately controlled by initial Emergency Room treatment. There may be gender differences in pain perception and response in acute sickle cell pain crisis.

[Interobserver correlation in the interpretation of 99mTc-sestamibi SPECT in reperfused acute myocardial infarction]

INTRODUCTION AND OBJECTIVES

The correct interpretation of myocardial perfusion single photon emission computed tomography (SPECT) requires knowledge of the technique reproducibility. The objective was analyze the interobserver correlation of different experience in the interpretation of myocardial perfusion SPECT in patients following acute myocardial infarction (AMI) in order to improve the quality of our site.

METHODS

Sixty cases (56 +/- 11 years, 87 % men) with transmural AMI who had recently undergone successful thrombolysis were included. Resting perfusion with (99m)Tc-sestamibi was performed at one week post-AMI.

ANALYSIS

Semiquantitative interpretation using 17 segment-model by 2 independent specialists and 5 observers, was performed blindly. Left ventricular ejection fraction (LVEF) was measured with isotopic ventriculography one month after AMI, with a mean of 38 %.

RESULTS

Using independent and then agreed on perfusion analysis, average involved segments/patient was 9.3 +/- 4 and the sum of severity 25 +/- 13. Readings of other observers ranged from 7 +/- 3.7 to 9.4 +/- 3.9 and 16.7 +/- 9.7 to 24.6 +/- 13, respectively, consistent with the reading of the specialists of between 0.779-0.871 (kappa: 0.565-0.741). There was no significant difference when the number of segments were analyzed in 40 % of the cases and for intensity in 60 % of them in more experienced observers. Correlation with consensus reading for the number of segments ranged from 0.84 to 0.94 and for severity from 0.79 to 0.89. Identification of culprit arteries was acceptable, with r values between 0.612 and 0.683 and kappas between 0.629 and 0.656. Correlation of the number of involved segments and severity with LVEF performed one month after AMI was 0.73 and 0.74, respectively.

CONCLUSIONS

There was good correlation in the interpretation of myocardial perfusion SPECT, with a significantly better fit in more experienced observers. This academic exercise was also helpful in improving our residents' skills in cardiology.

[Topical chemotherapy for actinic keratosis and nonmelanoma skin cancer: current options and future perspectives]

Actinic keratosis is currently considered not to be a precursor of squamous cell carcinoma but, rather, an initial stage of the disease. Furthermore, the incidence of both squamous cell carcinoma and basal cell carcinoma continues to increase. Topical drugs are now becoming widely used in the therapeutic management of nonmelanoma skin cancer and its precursor lesions. Here, we review the various topical drugs that are currently available and discuss their advantages and drawbacks. Therapeutic options include retinoids, 5-fluoracil, diclofenac, imiquimod, and photodynamic therapy.

Gene delivery into mouse retinal ganglion cells by in utero electroporation

Background

The neural retina is a highly structured tissue of the central nervous system that is formed by seven different cell types that are arranged in layers. Despite much effort, the genetic mechanisms that underlie retinal development are still poorly understood. In recent years, large-scale genomic analyses have identified candidate genes that may play a role in retinal neurogenesis, axon guidance and other key processes during the development of the visual system. Thus, new and rapid techniques are now required to carry out high-throughput analyses of all these candidate genes in mammals. Gene delivery techniques have been described to express exogenous proteins in the retina of newborn mice but these approaches do not efficiently introduce genes into the only retinal cell type that transmits visual information to the brain, the retinal ganglion cells (RGCs).

Results

Here we show that RGCs can be targeted for gene expression by in utero electroporation of the eye of mouse embryos. Accordingly, using this technique we have monitored the morphology of electroporated RGCs expressing reporter genes at different developmental stages, as well as their projection to higher visual targets.

Conclusion

Our method to deliver ectopic genes into mouse embryonic retinas enables us to follow the course of the entire retinofugal pathway by visualizing RGC bodies and axons. Thus, this technique will permit to perform functional studies in vivo focusing on neurogenesis, axon guidance, axon projection patterning or neural connectivity in mammals.

The retinal ganglion cell axon's journey: insights into molecular mechanisms of axon guidance

The developing visual system has proven to be one of the most informative models for studying axon guidance decisions. The pathway is composed of the axons of a single neuronal cell type, the retinal ganglion cell (RGC), that navigate through a series of intermediate targets on route to their final destination. The molecular basis of optic pathway development is beginning to be elucidated with cues such as netrins, Slits and ephrins playing a key role. Other factors best characterised for their role as morphogens in patterning developing tissues, such as sonic hedgehog (Shh) and Wnts, also act directly on RGC axons to influence guidance decisions. The transcriptional basis of the spatial-temporal expression of guidance cues and their cognate receptors within the developing optic pathway as well as mechanisms underlying the plasticity of guidance responses also are starting to be understood. This review will focus on our current understanding of the molecular mechanisms directing the early development of functional connections in the developing visual system and the insights these studies have provided into general mechanisms of axon guidance.