Acoustic waves improves retroviral transduction in human retinal stem cells.

BACKGROUNDS: The plasticity of retinal stem cells (RSCs), a type of cells that can differentiate into neuron cells and photoreceptor cells, endows them with potential therapeutic properties that can be applied to regenerative medicine. Gene modification of these stem cells before trans-differentiation and transplantation enhances their survival and increases their therapeutic function. The different ways to effectively deliver gene into RSCs are still discussed. This study aimed to use the acoustic waves to improve the efficacy of gene delivery for RSCs. METHODS: RSCs were obtained from non-fetal human ocular pigmented ciliary margin tissues. The enhanced green fluorescent protein-encoded murine stem cell retroviruses (MSCV) were prepared and used to infect RSCs. Glass chambers containing RSCs, retroviruses, and various concentrations of polybrene (0, 0.8, 2, 4 and 8 µg/mL) were exposed under 20 or 25 Vp-p ultrasonic standing wave fields (USWF) for 5 min. The percentage of green fluorescent protein positive cells in each sample was calculated and compared to test the efficacy of gene transduction. RESULTS: Our results showed that the efficiency of gene transduction by MSCV infection was enhanced following the concentration of polybrene and the energy of USWF. The percentage of green fluorescent protein positive cells was significantly higher in chambers that contained 8 µg/mL of polybrene and was exposed to 20Vp-p of USWF for 5 min. In addition, the percentage increased in chambers contained 2, 4 and 8 µg/mL of polybrene when they were exposed to 25Vp-p of USWF. Comparing to those did not treated with ultrasound, the efficiency of retroviral transduction to RSCs increased 4-fold after exposed to USWF for 5 min. CONCLUSION: We demonstrated the ability of ultrasound standing waves to improve retroviral transduction into RSCs. We believe that this may be applied to the experimental designs of future studies and may have possible therapeutic uses.

Allopurinol Use and Risk of Fatal Hypersensitivity Reactions: A Nationwide Population-Based Study in Taiwan.

IMPORTANCE: Allopurinol, a first-line drug used for treating gout, is increasingly prescribed worldwide to patients with asymptomatic hyperuricemia and comorbid renal or cardiovascular diseases. Nevertheless, allopurinol use has been associated with fatal hypersensitivity reactions, including drug rash with eosinophilia and systemic symptoms, Stevens-Johnson syndrome, and toxic epidermal necrolysis. The overall risks of allopurinol use remain unclear. OBJECTIVE: To investigate the incidence of, risk factors for, and mortality associated with allopurinol hypersensitivity in new users of allopurinol. DESIGN, SETTING, AND PARTICIPANTS: A retrospective nationwide population study was conducted using data from the Taiwan National Health Insurance Research Database, which includes detailed medical records of more than 23 million insured enrollees. Data were collected from January 1, 2005, through December 31, 2011, using the Anatomical Therapeutic Chemical classification system and International Classification of Diseases, Ninth Revision, Clinical Modification codes. Among 1,613,719 patients receiving allopurinol prescriptions, 495,863 were identified as new users. MAIN OUTCOMES AND MEASURES: Allopurinol hypersensitivity was identified within 3 months since the first prescription. The period for measuring related hospitalizations was 1 month since the episode, and the period for measuring renal complications or mortality was 2 months since the episode. Poisson regression test and multivariable logistic regression analysis were performed, and P < .01 was considered statistically significant. RESULTS: Among the more than 23 million insured enrollees, the annual incidence rates were 4.68 per 1000 new users for allopurinol hypersensitivity, 2.02 per 1000 new users for related hospitalization, and 0.39 per 1000 new users for related mortality. The annual incidence of allopurinol hypersensitivity rose statistically significantly during the study period (P < .001). Risk factors for allopurinol hypersensitivity included female sex, age 60 years or older, initial allopurinol dosage exceeding 100 mg/d, renal or cardiovascular comorbidities, and use for treating asymptomatic hyperuricemia. Patients with asymptomatic hyperuricemia and renal or cardiovascular diseases had statistically significantly increased risk of allopurinol hypersensitivity (odds ratio [OR], 1.61; 95% CI, 1.33-1.94; P < .001 for renal diseases and OR, 1.52; 95% CI, 1.19-1.93; P < .001 for cardiovascular diseases). They also had statistically significantly increased risk of mortality (OR, 5.59; 95% CI, 2.61-11.94; P < .001 for renal diseases and OR, 3.57; 95% CI, 2.31-5.51; P < .001 for cardiovascular diseases). CONCLUSIONS AND RELEVANCE: The use of allopurinol in patients with asymptomatic hyperuricemia accompanied by renal or cardiovascular diseases statistically significantly increased the risk of hypersensitivity reactions. Physicians should be cautious when prescribing allopurinol to high-risk populations and should consider the potential risks of fatal adverse reactions.