Differential expression of DAHP synthase and chorismate mutase isozymes during rhizogenesis of Brassica juncea cultured in vitro

The regulatory patterns of two of the enzymes of the shikimate pathway. 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase (DAHP synthase or DS. EC 4. 1. 2. 15) and chorismate motase (CM, EC 5. 4. 99. 5), were investigated using in vitro cultures of Brassica juncea at two stages, viz. undifferentiated, proliferating callus and the root-forming callus. Our studies revealed the presence of the two isozymes of DAHP synthase, DS-Mn and DS-Co. in undifferentiated callus. However, during the rhizogenesis of the callus DS-Mn was absent. Similarly, for chorismate mutase, whereas both the isozymes CM-1 and CM-2 were present in undifferentiated callus only CM-2 was detected at rhizogenesis. The possible involvement of these isozymes in callus growth and rhizogenesis is discussed.     

A comparison of biologically variable ventilation to recruitment manoeuvres in a porcine model of acute lung injury

BackgroundBiologically variable ventilation (return of physiological variability in rate and tidal volume using a computer-controller) was compared to control mode ventilation with and without a recruitment manoeuvre – 40 cm H₂O for 40 sec performed hourly; in a porcine oleic acid acute lung injury model.MethodsWe compared gas exchange, respiratory mechanics, and measured bronchoalveolar fluid for inflammatory cytokines, cell counts and surfactant function. Lung injury was scored by light microscopy. Pigs received mechanical ventilation (F_IO₂ = 0.3; PEEP 5 cm H₂O) in control mode until PaO₂ decreased to 60 mm Hg with oleic acid infusion (PaO₂/F_IO₂ <200 mm Hg). Additional PEEP to 10 cm H₂O was added after injury. Animals were randomized to one of the 3 modes of ventilation and followed for 5 hr after injury.ResultsPaO₂ and respiratory system compliance was significantly greater with biologically variable ventilation compared to the other 2 groups. Mean and mean peak airway pressures were also lower. There were no differences in cell counts in bronchoalveolar fluid by flow cytometry, or interleukin-8 and -10 levels between groups. Lung injury scoring revealed no difference between groups in the regions examined. No differences in surfactant function were seen between groups by capillary surfactometry.ConclusionsIn this porcine model of acute lung injury, various indices to measure injury or inflammation did not differ between the 3 approaches to ventilation. However, when using a low tidal volume strategy with moderate levels of PEEP, sustained improvements in arterial oxygen tension and respiratory system compliance were only seen with BVV when compared to CMV or CMV with a recruitment manoeuvre.     

Syngamosis,an unusual cause of asthma: the first reported case in Canada.

The first case of syngamosis in a human in Canada is reported. The patient, a traveller to the Caribbean islands, presented with a chronic dry cough. The nematode Syngamus laryngeus is found in wild and domestic birds and mammals in the tropics and subtropics. Humans are only accidental hosts. The diagnosis of syngamosis is usually made by fibreoptic bronchoscopic examination, which reveals the Y-shaped worms in the bronchi or the characteristic eggs in the sputum or feces. Physicians must be alerted to the possibility of syngamosis in patients with symptoms of asthma who have recently travelled to South America or the Caribbean islands.