PRESENTATION: A 76-year-old female presented with a history of non-exudative macular degeneration presented with a submacular hemorrhage (SMH) due to conversion to exudative macular degeneration in the left eye [Figure 1]. Visual acuity had decreased to 20/200. She underwent 23-gauge pars plana vitrectomy, subretinal injection of 0. 2 mL of 25 µ g/0. 1 mL Tissue Plasminogen Activator (tPA) at 2 mm superotemporally to the hemorrhage, and 12% C3F8 gas fill. She postured supine with a 30° forward head tilt for five days to facilitate displacement of the hemorrhage inferiorly. Two weeks after the operation, the hemorrhage had largely cleared, and her vision improved to 20/80, but she developed a crescent-shaped area of retinal pigment epithelium (RPE) atrophy extending beyond the area of tPA injection, with relative sparing of the posterior pole. . .

Low molecular size additives such as L-arginine and the redox compounds have been used both in the culture medium and in vitro refolding to increase recombinant proteins production. Additives increase protein refolding and yield of active proteins by suppressing aggregate formation or enhancing refolding process.In this work, a comparative study was performed on refolding of recombinant Plasminogen Activator (rPA) in the presence of different concentrations of denaturants and additives. Escherichia coli-expressed rPA inclusion bodies were solubilized in chaotropic denaturants and subjected to protein refolding by dilution method. The effects of various additives, the impact of pH, residual Guanidin Hydrochloride (Gn-HCl) and Dithiothreitol (DTT) on refolding process were investigated.The refolding process was assessed by determination of protein solubility and biological assay. The results of the study demonstrated that the best condition for solubilizing the rPA inclusion body was 6M guanidine hydrochloride at pH=10. In refolding step, Larginine showed increasing effect on suppression of aggregation at concentrations of 200-1000 mM.Glutathione pairs (GSH-GssG) showed refolding enhancer effect in a range of 2-20 mM. The highest refolding yield was obtained in 500 mM L-arginine and reduced/oxidized glutathione 10: 1 ratio in pH 10. In conclusion, the results show that L-arginine plays an important role in the refolding of human PA, preventing the aggregation of folding intermediate, and glutathione pair is essential for the correct refolding. The results also revealed that higher solubility in the presence of higher concentration of L-arginine (>500 mM) or pH (>10) is not associated with higher activity.

Introduction: At present, most recombinant proteins are produced in prokaryotes especially E coli. Yeasts and CHO also are used as eukaryotic hosts. Leishmania tarentolae, a parasite of lizards, a member of Trypanosomatidae family is one of the new systems for expression of heterologous proteins. In this system, some of the parasitic protozoa features are used in expression of mammalian proteins.Material and Methods: For evaluation of the protozoa for expression of human complex proteins, we cloned cDNA of tPA gene containing native human signal sequence. We used vectors containing 3´ and 5´ sequences of Leishmania 18s rRNA for integration of the vectors in 18s rRNA gene and severe transcription.Results: RT-PCR test showed production of specific mRNA of tPA gene in the recombinant cells. Southern blot analysis confirmed the cloning of t-PA in the genome of the Leishmania.Conclusion: This study showed native human signal sequence mediate transport and secretion of the protein. Hence, L. tarentolae is the first useful biotechnologically protozoan and tPA is the most complex protein expressed in it.

Purpose: To compare the effect of Tissue Plasminogen Activator (TPA) and aspirin in patients with central retinal vein occlusion.Methods: A prospective interventional study was conducted on patients with central retinal vein occlusion of less than 28 days' duration. Patients in the TPA group received 100 mg intravitreal Tissue Plasminogen Activator and the patients who declined intravitreal injection were considered as Aspirin group. Patients were followed up for 6 months.Results: sixty five patients were enrolled, 19 in the TPA group and 46 in the Aspirin group. The mean 6-month change in visual acuity for TPA-treated patients was -0.29±0.42 (range: -1.4 to +0.5) while in the Aspirin group, it was 0.28±0.79 with a range of -1 to +2.5. TPA group had a significantly better visual improvement in comparison to Aspirin group (P<0.0005). Conclusion: Intravitreal Tissue Plasminogen Activator can be injected safely and easily. Patients treated with intravitreal Tissue Plasminogen Activator within 28 days of the onset of central retinal vein occlusion are more likely to improve visual acuity.

Purpose: The purpose of this study is to investigate the efficacy of recombinant Tissue Plasminogen Activator (r-tPA) in treatment of postsurgical fibrinous membrane and to experience the special and relatively difficult process of preparing and preserving this drug.Patients and Methods: In a prospectivestudy, 5 eyes of 5 patients with thick fibrin membrane following anterior segment surgery received 20 μg r-tPA intracamerally through a paracentesis.Results: Complete fibrinolysis occurred 2-20 h after injection in 3 eyes without any complication or recurrence over the three months follow up. In one case with a thick fibrin membrane for 3 months, r-tPA injection failed. In one patient, the membrane disappeared completely during the first 24 h after injection, but recurred 1 week later due to underlying mild endophthalmitis.Conclusion: The authors believe that intraocular r-tPA is effective and relatively safe in the treatment of severe therapy-resistant cases of intracameral fibrin reaction, if given at appropriate time.

Background: Cerebrovascular diseases are the second common cause of mortality worldwide. The onset of reperfusion in the first 3-4. 5 hours is a predictive factor of treatment. Objective: The present study investigated barriers to receiving Tissue Plasminogen Activator in patients with ischemic stroke. Methods: This cross-sectional study examined 191 patients with first-ever stroke referring to the emergency department of the Persian Gulf Martyrs Hospital of Bushehr City, Iran, in 2016. One checklist was completed which included demographic data, history of diseases, knowledge of stroke symptoms, and intervals regarding the onset of symptoms to informing emergency, informing emergency on arrival at the emergency department of the hospital, and making the diagnosis for the patients. The obtained data were analyzed in SPSS v. 19. Results: Mean± SD age of the patients was 65. 92± 12. 48 years. The majority of patients under investigation (55. 5%) were female, 63. 4% were married, 56% were illiterate and 72. 3% resided in other districts of Bushehr province. Mean duration between onset of symptoms and arrival at emergency department, onset of symptoms and call the emergency service, time of arrival at emergency department to perform brain Computer Tomography (CT) scan and also to be counseled by a neurologist were 699. 66, 195. 51, 45. 11 and 423. 62 minutes, respectively. Finally 14. 6 percent of patients were qualified to be treated with tPA. Conclusion: The main barrier to timely therapy is a delay in golden time. Therefore, public education to promote public awareness could be of great benefit in reducing the referral delay time.