A new silver sulfadiazine water soluble gel

Silver sulfadiazine is the most commonly used topical antibacterial agent for the treatment of burn wounds. It has many clinical advantages, including a broad spectrum of antimicrobial activity, low toxicity, and minimal pain on application. The current formulation of silver sulfadiazine contains a lipid soluble carrier, polypropylene glycol, that has certain disadvantages, including pseudo-eschar formation and the need for twice daily application. The purpose of this investigation was to describe a new formulation of silver sulfadiazine in a water soluble gel, poloxamer 188. The antibacterial activity of this new gel has been compared to that of the commercially available silver sulfadiazine cream by in vitro and in vivo testing. The results of the in vitro antibacterial testing of these two different agents demonstrated the superiority of the new gel formulation. In experimental wounds, the antibacterial activity of the gel and the commercially available silver sulfadiazine cream were not significantly different when applied once a day. The antibacterial activity of the gel when applied once a day was comparable to that encountered by twice daily applications of the silver sulfadiazine cream by experimental wounds. The major advantage of this gel was its ease of application and removal that is attributed to its water solubility.     

Mutations in purine nucleoside phosphorylase deficiency

PURPOSE: The aim of this study was to investigate the incidence of unexpected malignant uveal melanoma in the age of ultrasound diagnostics and to highlight the reasons for misdiagnosis. PATIENTS AND METHODS: All eyes were surgically removed and histologic examination was performed between 1981 and 1995. The eyes were investigated for the incidence of uveal melanoma, and the history of the unexpected malignant melanoma of the uvea or ciliary body highlighted. RESULTS: 225 (18.7%) eyes with malignant melanoma out of 2583 enucleated eyes were found. Eight (3.6%) of 225 were clinically unexpected. The clinical misdiagnoses were secondary angle closure or open angle glaucoma (6), retinal detachment (5), iritis (1), scleritis (1), cataract (4) and an intraocular mass that was believed to be a metastasis of a colon carcinoma. Seven of eight eyes were blind, and one eye had light perception only. The longest follow up before enucleation was 13 years. On three eyes diagnostic ultrasound was reportedly performed without specific diagnosis of uveal melanoma. Surgery was performed on four eyes for reasons of uncontrollable intraocular pressure or retinal detachment up to five years before enucleation. Histologic diagnoses were 3 epitheloid-type, 2 spindel-type and 3 necrotic melanoma of the uvea. Four eyes showed scleral invasion by tumor cells and one eye an invasion into the episcleral space. CONCLUSIONS: Even today the rate of unexpected uveal melanoma, according to our study is 3.6%. Therefore, all blind eyes without visualisation of the posterior pole should be examined with ultrasound in order to diagnose an uveal melanoma prior to enucleation.     

The preparation of an amino acid-based surfactant and its potential application as an EOR agent

Most of the synthetic surfactants investigated with the aim of enhanced chemically oil recovery in the literature have environmental drawbacks. In this work, application of an environmentally-friendly synthetic surfactant as an enhanced oil recovery agent is introduced by measuring interfacial tension of water–kerosene systems and wettability alteration of carbonate pellets. For this purpose, an amino acid-based surfactant was initially synthesized using a new synthetic approach which was subsequently confirmed by spectra of Fourier transform infrared and Proton nuclear magnetic resonance. Results showed a value of critical micelle concentration in the range of 9000–9100 ppm for this surfactant. Results also demonstrated a decrease of 38.53% in water–kerosene system interfacial tension and a 17.76% reduction in oil-wetness of the carbonate pellets.     

Modeling of CO2-brine interfacial tension: Application to enhanced oil recovery

Development of reliable and accurate models to estimate carbon dioxide–brine interfacial tension (IFT) is necessary, since its experimental measurement is time-consuming and requires expensive experimental apparatus as well as complicated interpretation procedure. In the current study, feed forward artificial neural network is used for estimation of CO₂–brine IFT based on data from published literature which consists of a number of carbon dioxide–brine interfacial tension data covering broad ranges of temperature, total salinity, mole fractions of impure components and pressure. Trial-and-error method is utilized to optimize the artificial neural network topology in order to enhance its capability of generalization. The results showed that there is good agreement between experimental values and modeling results. Comparison of the empirical correlations with the proposed model suggests that the current model can predict the CO₂–brine IFT more accurately and robustly.     

Morphological changes in vero cells postinfection with dengue virus type‐2

Although no specific antiviral tablets or injections that can kill the dengue virus are currently available, adequate care and treatment could control its morbidity. Interaction of dengue virus to target cells could be an important feature for virus propagation. Ultrastructural analysis of this interaction was studied with vero cells. Vero cells were treated with Dengue virus type‐2 at different time intervals at multiplicity of infection (m.o.i) < 10, m.o.i > 10, and m.o.i = 100. It was found that m.o.i < 10 is best to study morphological changes. At an m.o.i > 10 apoptosis occurs and at m.o.i. = 100, cell necrosis occurs. While studying morphological changes, it was found that at 30 min postinfection cells have morphology very similar to that of the control cells although some have irregular outline and show cytoplasmic projections and intense cytoplasmic vacuolization. After 1–12 hours postinfection (h.p.i), the nuclei ran from normal looking to diffuse. Nuclear membrane begins to disintegrate. Some nucleoli are difficult to be seen. The cytoplasm appears as a mottled, lumps diffuse mass distributed throughout the cytosol, with dense lysosomes and myelin figures, also in the mitochondria. In later hours (24 h.p.i), the intranuclear euchromatin is dispersed and heterochromatin forms peripheral clumps. The cytoplasmic processes are short and few in numbers. A proportion of damaged mitochondria with disrupted cristae appear, suggesting that dengue virus may induce mitochondrial dysfunction and nucleus and mitochondria may be the primary organelles helping in dissemination of virus. Microsc. Res. Tech. 2011. © 2010 Wiley‐Liss, Inc.     

Risks and benefits of diagnostic angiography after aneurysm surgery: a retrospective analysis of 597 studies

INTRODUCTION: Cerebral angiography performed after aneurysm surgery can identify causes of morbidity and mortality that may be corrected. The risks and benefits of angiography that is performed after aneurysm surgery, however, have not been clearly defined. We therefore reviewed our experience with postoperative angiography to determine its dangers and benefits. METHODS: During 10 years, 543 consecutive patients received treatment for cerebral aneurysms. A retrospective analysis of 597 diagnostic angiograms obtained after aneurysm surgery for 494 of these patients was performed. RESULTS: Catheter-induced vessel spasm and dissection, occurring most frequently in the internal carotid artery, were observed in seven (1.2%) and six (1%) studies, respectively. No angiography-associated strokes were identified. No association between age, smoking, hypertension, blood pressure, atherosclerosis, or severe vasospasm and angiographic complications was observed. Aneurysm remnants were identified in 36 (5.7%) of the 637 aneurysms that were surgically treated. Atherosclerosis (P < 0.01) or multiple clip applications (P < 0.01) were significantly associated with aneurysm remnants. Angiographic vessel occlusion was observed in 28 (5.7%) patients and resulted in stroke in 14 of these patients. Vessel occlusion was significantly associated with increasing aneurysm size (P < 0.001), atherosclerosis (P < 0.001), temporary clips (P < 0.001), multiple clips (P=0.03), multiple clip applications (P=0.001), and a new postoperative neurological deficit (P=0.002). Severe vasospasm and newly identified aneurysms were observed in 51 and 16 patients, respectively. CONCLUSION: Angiography after aneurysm surgery is safe and can be routinely performed. Angiography after aneurysm surgery should be particularly considered for patients with large aneurysms or cerebrovascular atherosclerosis and for those who develop new postoperative neurological deficits.     

Membrane targeting of RecA during genetic transformation

Recombination in prokaryotes and eukaryotes is mediated by the RecA family of proteins. Although the interactions between RecA and DNA are well studied, the cellular location of these interactions is not known. Using genetic transformation of Streptococcus pneumoniae as a model system, there was increased expression of a protein, colligrin, and RecA, products of the rec locus during genetic transfer. These proteins formed a complex and were found associated with the membranes of genetically competent cells. With immunoelectron microscopy and subcellular fractionation, we showed that the induction of competence led to the translocation of RecA and colligrin to the membrane and to the formation of clusters of RecA in a colligrin-dependent step. Based on the behaviour of colligrin and RecA during genetic exchange and the numerous proteins in prokaryotes and eukaryotes with domains similar to colligrin, we suggest that there may exist a family of proteins, which gathers macromolecules at specific sites in biological membranes.