Indomethacin-Dipalmitoylphosphatidylcholine Interaction. A Calorimetric Study of Drug Release from Poly(Lactide-co-glycolide) Microspheres into Multilamellar Vesicles

A comparative study of indomethacin controlled release from poly(lactide-co-glycolide) (50:50, molecular weight 3000) (PLGA) microspheres loaded with two different amounts of drug (10.9 ± 1%, and 34.1 ± 1% w/w) and pure free indomethacin, considering the effects exerted by the drug on the thermotropic behavior of dipalmitoylphosphatidylcholine multilamellar vesicles, was carried out by differential scanning calorimetry (DSC). The release was monitored by comparing the effect exerted by the free indomethacin on lipid thermotropic behavior with that of the drug released by the microspheres and relating these effects to a lipid aqueous dispersion containing the molar ratio of drug able to cause it. By DSC measurements, the pure free indomethacin was found to be able to have a fluidifying effect on the model membrane, causing a shift toward lower values of the transitional temperature (T_m), characteristic of phospholipid liposomes, without variations in the enthalpic changes (ΔH). This shift was found to be modulated by the drug molar fraction with respect to the lipid concentration in the aqueous dispersion. Successively, calorimetric measurements were performed on suspensions of blank liposomes added to weighed amounts of unloaded and indometha-cin-loaded microspheres as well as free powdered indomethacin, and the T_m shifts of the lipid bilayer caused by the drug released from the polymeric system, as well as by the free drug, were compared with that caused by free drug increasing molar fractions dispersed directly on the membrane, employed as a calibration curve to obtain the fraction of drug released. This drug release model could be employed to determine the different kinetics involved in the drug transfer from the microspheres to a membrane. This in vitro study suggests that the kinetic process involved in drug release is influenced by the amount of drug loaded in the microspheres. This calorimetric study shows that the PLGA microspheres are a good delivery system able to sustain drug release. Moreover, the DSC technique applied to the drug interaction with biomembranes constitutes a good tool for determining the drug release representing an innovative alternative in vitro model.     

De novo engineering of reticular connective tissue in vivo by silk fibroin nonwoven materials

Biologically tolerated biomaterials are the focus of intense research. In this work, we examined the biocompatibility of three-dimensional (3D) nonwovens of sericin-deprived, Bombyx mori silk fibroin (SF) in beta-sheet form implanted into the subcutaneous tissue of C57BL6 mice, using sham-operated mice as controls. Both groups of mice similarly healed with no residual problem. Macroarray analysis showed that an early (day 3) transient expression of macrophage migration inhibitory factor (MIF) mRNA, but not of the mRNAs encoding for 22 additional proinflammatory cytokines, occurred solely at SF-grafted places, where no remarkable infiltration of macrophages or lymphocytes subsequently happened. Even an enduring moderate increase in total cytokeratins without epidermal hyperkeratosis and a transient (days 10-15) upsurge of vimentin occurred exclusively at SF-grafted sites, whose content of collagen type-I, after a delayed (day 15) rise, ultimately fell considerably under that proper of sham-operated places. By day 180, the interstices amid and surfaces of the SF chords, which had not been appreciably biodegraded, were crammed with a newly produced tissue histologically akin to a vascularized reticular connective tissue, while some macrophages but no lymphocytic infiltrates or fibrous capsules occurred in the adjoining tissues. Therefore, SF nonwovens may be excellent candidates for clinical applications since they both enjoy a long-lasting biocompatibility, inducing a quite mild foreign body response, but no fibrosis, and efficiently guide reticular connective tissue engineering.     

Repeated injection of botulinum toxin a in patients with neurogenic bladder: our experience

Background: In literature, the majority of data about treatment with botulinum toxin A are based on the results of a single treatment. We evaluate the safety and effectiveness in the medium term of the use of botulinum toxin type A in patients with neurogenic bladder, taking into consideration the clinical and urodynamic parameters, particularly in cases with repeated injections. Methods: 25 patients were divided into 2 groups: a first group of patients with detrusor overactivity, and a second with overactive sphincter. We performed 20-30 injections (Dysport), at a dose ranging between 500 and 1000 U. The first group was treated with infiltration in the detrusor and in the detrusor and trigone. The second group received injections in the perisphinteric zone, and in the?perisphinteric zone and bladder neck. Of the 25 patients, 12 received a retreatment: the first group of patients kept a daily voiding diary to record the number of bladder emptying, incontinence episodes, nycturia and urgency of urination. The urodynamic parameters and symptoms pre-treatment and 4 months after the treatment were compared in both groups. Results: In the first group there were significant changes in the cystometric capacity, maximum detrusor pressure, and in the post-void residual urine 4 months after treatment. These patients were satisfied with the treatment because of the improvement of incontinence and episodes of urgency. In 9 out of 15 retreated patients, the therapeutic results were similar to the first treatment. The second group reported significant improvements in maximum urinary flow rate, post-void residual urine and maximum detrusor pressure. 3 out of 10 patients were retreated even in this group; the new therapeutic results were similar to the first treatment. Conclusions: Our results in 25 patients with neurogenic bladder showed a concordance with the literature data. The treatment of detrusor and sphincter neurogenic overactivity with botulinum toxin A is effective and safe. Also in the 12 patients with repeated injection treatment, it has been proven safe and effective.     

Primary Stroke in a Woman With Sickle Cell Anemia Responsive to Hydroxyurea Therapy

The most common cause of stroke in children with sickle cell anemia is infarction due to ischemia. In adults, however, stroke is most commonly hemorrhagic in nature. Other causes of stroke in patients with sickle cell disease are very rare. In this short communication, we describe a woman with sickle cell anemia responsive to hydroxyurea (HU) therapy who had primary stroke due to paradoxical embolization caused by a large atrial septal defect. Successful management of the stroke included surgical closure of the defect with trans-esophageal echocardiographic guidance. To the best of our knowledge, this is the first patient with sickle cell anemia and stroke due to congenital heart disease who did not require open heart surgery for successful management.     

Lingual angioedema after alteplase treatment in a patient with acute ischemic stroke

BACKGROUND: In recent years, thrombolytic therapy has become the main treatment of ischemic stroke. But the increasing use of alteplase in ischemic stroke has made some complications more evident. Angioedema is a rare but potentially life-threatening complication of alteplase treatment. Only a few studies have examined the incidence of angioedema after treatment with alteplase for stroke.METHODS: A 75-year-old man complaining of right hemiparesis was admitted to our emergency department. He was diagnosed as having acute ischemic stroke, and alteplase infusion was given two hours after the onset of stroke symptoms. Immediately after the completion of infusion he was noted to have a large swollen tongue.RESULTS: His neurological symptoms resolved gradually within 4 hours, whereas his upper extremity strength improved to 4/5 and lower extremity 5/5. Lingual edema resolved within 16 hours without any complication. He died from presumed nosocomial infection 5 days later.CONCLUSIONS: Lingual angioedema may appear as a possible complication in patients who were treated with alteplase. The management of these patients should be very careful.     

Excessive daytime sleepiness and fatigue in neurological disorders

Sleep and Breathing - Excessive daytime sleepiness (EDS) and fatigue are some of the most frequent symptoms in neurological diseases and could impact on quality of life by increasing the risk of...