Long term features of diabetic retinopathy in streptozotocin-induced diabetic Wistar rats.

Diabetic retinopathy is a complication of diabetes and a leading cause of vision loss among working-age adults. To assess whether the Wistar rat with Streptozotocin (STZ)-induced diabetes is a suitable animal model of human proliferative diabetic retinopathy we evaluated the vascular changes to assess the diabetic retinopathy (DR) stages in this model. After two weeks of intraperitoneal STZ (55 mg/kg) injection in male Wistar rats (270-300 g), they were considered diabetic with persistent blood glucose levels ≥ 16.65 mmol/L. The diabetic and control rats were investigated after 1, 3, 6 and 9 months by electroretinography, Evans blue assay, dextran fluorescence retinal angiography, and retinal histopathological studies. Retinal vascular permeability in the diabetic groups increased significantly in all diabetic groups. The amplitude of a- and b-waves decreased significantly in all diabetic groups compared with the age-matched control groups. The latent time of a-waves in the diabetic groups was delayed at 3 months of diabetes and this delay remained relatively constant till 9 months following the onset of diabetes. Although the latent time of b-wave in the diabetic groups increased slightly, a significant difference was found right at 9 months of diabetes. Vascular density and branching point numbers significantly decreased in the diabetic eyes at 3 and 6 months while they increased at 9 months, which was not significant. Intraretinal hemorrhage and ischemic changes were detected in the half of diabetic rats after 6 months and considered as preproliferative stage of diabetic retinopathy. Although preproliferative changes were detected in all diabetic rats at 9 months, half of them showed vitreous neovascularization attached to retina and retinal folds which can be considered as proliferative stage of DR. Intraretinal hemorrhage, extensive leakage of fluorescein, retinal folds, and vitreous neovascularization were the most prominent findings of severe and proliferative diabetic retinopathy in a fraction of the STZ-induced diabetic rats which were comparable to that of the human patients. STZ-induced diabetic rats can be considered to be a potentially useful model for studies on pathogenesis and treatment of diabetic retinopathy in human.

Topical Tranexamic Acid Compared With Anterior Nasal Packing for Treatment of Epistaxis in Patients Taking Antiplatelet Drugs: Randomized Controlled Trial.

OBJECTIVE: We evaluated the efficacy of topical application of the injectable form of tranexamic acid (TXA) compared with anterior nasal packing (ANP) for the treatment of epistaxis in patients taking antiplatelet drugs (aspirin, clopidogrel, or both) who presented to the emergency department (ED). METHODS: A randomized, parallel-group clinical trial was conducted at two EDs. A total of 124 participants were randomized to receive topical TXA (500 mg in 5 mL) or ANP, 62 patients per group. The primary outcome was the proportion of patients in each group whose bleeding had stopped at 10 minutes. Secondary outcomes were the rebleeding rate at 24 hours and 1 week, ED length of stay (LOS), and patient satisfaction. RESULTS: Within 10 minutes of treatment, bleeding was stopped in 73% of the patients in the TXA group, compared with 29% in the ANP group (difference = 44%, 95% confidence interval, 26% to 57%; p < 0.001). Additionally, rebleeding was reported in 5 and 10% of patients during the first 24 hours in the TXA and the ANP groups, respectively. At 1 week, 5% of patients in the TXA group and 21% of patients in the ANP group had experienced recurrent bleeding (p = 0.007). Patients in the TXA group reported higher satisfaction scores (median [interquartile range {IQR}], 9 [8-9.25]) compared with the ANP group (median [IQR] = 4 [3-5]; p < 0.001). Discharge from the ED in <2 hours was achieved in 97% of patients in the TXA group versus 13% in the ANP group (p < 0.001). There were no adverse events reported in either group. CONCLUSIONS: In our study population, epistaxis treatment with topical application of TXA resulted in faster bleeding cessation, less rebleeding at 1 week, shorter ED LOS, and higher patient satisfaction compared with ANP.

Estradiol attenuates spinal cord injury-related central pain by decreasing glutamate levels in thalamic VPL nucleus in male rats.

Central neuropathic pain (CNP) is a complicated medical problem that involves both the spinal and supraspinal regions of the central nervous system. Estrogen, a neuroprotective agent, has been considered a possible candidate for CNP treatment. In this study, we examined the effects of a single dose of 17ß-estradiol on glutamate levels in the ventral posterolateral (VPL) nucleus of the rat thalamus. Furthermore, we determined whether there was a correlation between glutamate levels and neuropathic pain induced by unilateral electrolytic spinothalamic tract (STT) lesion. STT lesioning was performed in male Wistar rats at the T8-T9 vertebrae; rats were then administered 17ß-estradiol (4 mg/kg, i.p.) 30 min after injury. Glutamate samples were collected using a microdialysis probe and quantified by high performance liquid chromatography. Mechanical allodynia (MA) and thermal hyperalgesia (TH) thresholds were measured pre-injury and 7, 14, and 28 days post-injury. We found that STT lesion significantly increased glutamate levels in the ipsilateral VPL nucleus 14 and 28 days post-injury; this was accompanied by allodynia and hyperalgesia in the hind paws of the rats. Administering 17ß-estradiol to the rats decreased glutamate levels in the ipsilateral VPL nucleus and significantly increased MA and TH thresholds. These results suggest that glutamate in the VPL nucleus of the thalamus is involved in the pathology of neuropathic pain after STT injury; furthermore, 17ß-estradiol may attenuate this neuropathic pain by decreasing glutamate levels.

A new and rapid method for epistaxis treatment using injectable form of tranexamic acid topically: a randomized controlled trial.

OBJECTIVE: Epistaxis is a common problem in the emergency department (ED). Sixty percent of people experience it at least once in their life. There are different kinds of treatment for epistaxis. This study intended to evaluate the topical use of injectable form of tranexamic acid vs anterior nasal packing with pledgets coated with tetracycline ointment. METHODS: Topical application of injectable form of tranexamic acid (500 mg in 5 mL) was compared with anterior nasal packing in 216 patients with anterior epistaxis presented to an ED in a randomized clinical trial. The time needed to arrest initial bleeding, hours needed to stay in hospital, and any rebleeding during 24 hours and 1 week later were recorded, and finally, the patient satisfaction was rated by a 0-10 scale. RESULTS: Within 10 minutes of treatment, bleedings were arrested in 71% of the patients in the tranexamic acid group, compared with 31.2% in the anterior nasal packing group (odds ratio, 2.28; 95% confidence interval, 1.68-3.09; P < .001). In addition, 95.3% in the tranexamic acid group were discharged in 2 hours or less vs 6.4% in the anterior nasal packing group (P < .001). Rebleeding was reported in 4.7% and 11% of patients during first 24 hours in the tranexamic acid and the anterior nasal packing groups, respectively (P = .128). Satisfaction rate was higher in the tranexamic acid compared with the anterior nasal packing group (8.5 ± 1.7 vs 4.4 ± 1.8, P < .001). CONCLUSIONS: Topical application of injectable form of tranexamic acid was better than anterior nasal packing in the initial treatment of idiopathic anterior epistaxis.

Treadmill exercise reduces self-administration of morphine in male rats.

Exercise can activate the same pathways as morphine. The aim of the present study was to clarify the effect of short-term and mid-term exercises on the self-administration of morphine in rats. Male Wistar rats were initially trained to receive small pellets of food by pressing the active lever in self-administration apparatus. Rats were divided into 4 groups: Saline, Morphine, Exercise 1 (11 days) and Exercise 2 (30 days). Their jugular vein was cannulated. The animals were placed in self-administration apparatus and allowed to self-administer morphine (0.5mg per infusion all test groups) or saline (Saline group) during consecutive days, for 2h/sessions. In the group 1 the rats were running before each session of self-administration and of group Exercise 2, 30 days before surgery as well as before each session. The pressing numbers of active and passive levers in each group and among different groups were compared. The number of active lever pressing of Morphine group was significantly higher than Saline group (p<0.001). In Exercise 1 and Exercise 2 groups, the number of active lever pressing was significantly lower than Morphine group (p<0.001). As exercise can activate many neurotransmitter systems involved in the addiction process and increase the release of endorphins, it is likely that could decrease the morphine self-administration in this experimental setup.