This work investigates the effect of heterocyst toward biohydrogen production by A. variabilis. The heterocyst frequency was artificially promoted by adding an amino acid analog, in this case DL-7-azatryptophan into the growth medium. The frequency of heterocyst differentiation was found to be proportional to the concentration of azatryptophan (0-25 µM) in the medium. Conversely, the growth and nitrogenase activity were gradually suppressed. In addition, there was also a distinct shortening of the cells filaments and detachment of heterocyst from the vegetative cells. Analysis on the hydrogen production performance revealed that both the frequency and distribution of heterocyst in the filaments affected the rate of hydrogen production. The highest hydrogen production rate and yield (41 µmol H2 mg chl a(-1) h(-1) and 97 mL H2 mg chl a(-1), respectively) were achieved by cells previously grown in 15 µM of azatryptophan with 14.5 % of heterocyst frequency. The existence of more isolated heterocyst has been shown to cause a relative loss in nitrogenase activity thus lowering the hydrogen production rate.
Post-thoracotomy paraplegia after non-aortic surgery is an extremely uncommon complication. A 56-year-old woman presented with a 1-year history of progressive shortness of breath. Computed tomography revealed a locally advanced posterior mediastinal mass involving the ribs and the left neural foramina. Tumor excision with a left pneumonectomy was performed. Post-resection, bleeding was noted in the vicinity of the T4-T5 vertebral body, and the bleeding point was packed with oxidized cellulose gauze (Surgicel®). Postoperatively, the patient complained of bilateral leg numbness extending up to the T5 level, with bilateral paraplegia. An urgent laminectomy was performed, and we noted that the spinal cord was compressed by two masses of Surgicel® with blood clots measuring 1.5 × 1.5cm at T4 and T5 levels. The paraplegia did not improve despite the removal of the mass, sufficient decompression, and aggressive postoperative physiotherapy. Surgeons operating in fields close to the intervertebral foramen should be aware of the possible threat to the adjacent spinal canal as helpful hemostatic agents can become a preventable threat.
Australia's cervical screening program transitioned from cytology to HPV-testing with genotyping for HPV16/18 in Dec'2017. We investigated whether program data could be used to monitor HPV vaccination program impact (commenced in 2007) on HPV16/18 prevalence and compared estimates with pre-vaccination benchmark prevalence. Pre-vaccination samples (2005-2008) (n = 1933; WHINURS), from 25 to 64-year-old women had been previously analysed with Linear Array (LA). Post-vaccination samples (2013-2014) (n = 2989; Compass pilot), from 25 to 64-year-old women, were analysed by cobas 4800 (cobas), and by LA for historical comparability. Age standardised pre-vaccination HPV16/18 prevalence was 4.85% (95%CI:3.81-5.89) by LA; post-vaccination estimates were 1.67% (95%CI:1.21-2.13%) by LA, 1.49% (95%CI:1.05-1.93%) by cobas, and 1.63% (95%CI:1.17-2.08%) for cobas and LA testing of non-16/18 cobas positives (cobas/LA). Age-standardised pre-vaccination oncogenic HPV prevalence was 15.70% (95%CI:13.79-17.60%) by LA; post-vaccination estimates were 9.06% (95%CI:8.02-10.09%) by LA, 8.47% (95%CI:7.47-9.47%) by cobas and cobas/LA. Standardised rate ratios between post-vs. pre-vaccination rates were significantly different for HPV16/18, non-16/18 HPV and oncogenic HPV: 0.34 (95%CI:0.23-0.50), 0.68 (95%CI:0.55-0.84) and 0.58 (95%CI:0.48-0.69), respectively. Additional strategies (LA for all cobas positives; combined cobas and LA results on all samples) had similar results. If a single method is applied consistently, it will provide important data on relative changes in HPV prevalence following vaccination.