Ciliated epithelia produce fluid flow in many organ systems, ranging from the respiratory tract where it clears mucus to the ventricles of the brain where it transports cerebrospinal fluid. Human diseases that disable ciliary flow, such as primary ciliary dyskinesia, can compromise organ function or the ability to resist pathogens, resulting in recurring respiratory infections, otitis, hydrocephaly and infertility. To create a ciliary flow, the cilia within each cell need to be polarized coordinately along the planar axis of the epithelium, but how polarity is established in any ciliated epithelia is not known. Here we analyse the developmental mechanisms that polarize cilia, using the ciliated cells in the developing Xenopus larval skin as a model system. We show that cilia acquire polarity through a sequence of events, beginning with a polar bias set by tissue patterning, followed by a refinement phase. Our results indicate that during refinement, fluid flow is both necessary and sufficient in determining cilia polarity. These findings reveal a novel mechanism in which tissue patterning coupled with fluid flow act in a positive feedback loop to direct the planar polarity of cilia.

To discern whether the characteristics and outcome of invasive aspergillosis in liver transplant recipients have evolved during the past decade, 26 patients who underwent transplantation during 1990-1995 (known as "the earlier cohort") were compared with 20 patients who underwent transplantation during 1998-2001 (known as "the later cohort"). Twenty-three percent of the Aspergillus infections in the earlier cohort occurred у90 days after transplantation, compared with 55% of such infections in the later cohort ( ). The earlier cohort P p .026 was significantly more likely to have disseminated infection ( ) and central nervous system (CNS) in-P p .034 volvement ( ) than was the later cohort. The mortality rate was significantly higher for the earlier cohort P p .0004 (92%) than for the later cohort (60%;). Only disseminated infection (not the year of transplantation) P p .012 approached statistical significance as an independent predictor of outcome. In the current era, invasive aspergillosis occurs later in the posttransplantation period, is less likely to be associated with CNS infection, and is associated with a lower mortality rate, compared with invasive aspergillosis in the early 1990s.Invasive aspergillosis has long been recognized as one of the most significant opportunistic fungal infections in liver transplant recipients [1][2][3][4]. The frequency of invasive aspergillosis among liver transplant recipients ranges from 1% to 6% [2]. However, the mortality rate for these patients exceeds 90% [1,5]; an estimated 16.9% of all deaths that have occurred among liver

To determine the spectrum and impact of mycelial fungal infections, particularly those due to non-Aspergillus molds, 53 liver and heart transplant recipients with invasive mycelial infections were prospectively identified in a multicenter study. Invasive mycelial infections were due to Aspergillus species in 69.8% of patients, to non-Aspergillus hyalohyphomycetes in 9.4%, to phaeohyphomycetes in 9.4%, to zygomycetes in 5.7%, and to other causes in 5.7%. Infections due to mycelial fungi other than Aspergillus species were significantly more likely to be associated with disseminated (P=.005) and central nervous system (P=.07) infection than were those due to Aspergillus species. Overall mortality at 90 days was 54.7%. The associated mortality rate was 100% for zygomycosis, 80% for non-Aspergillus hyalohyphomycosis, 54% for aspergillosis, and 20% for phaeohyphomycosis. Thus, non-Aspergillus molds have emerged as significant pathogens in organ transplant recipients. These molds are more likely to be associated with disseminated infections and to be associated with poorer outcomes than is aspergillosis.

We have reconstituted the fusion and assembly of vesiculated Golgi membranes (VGMs) into functionally active stacks of cisternae. A kinetic analysis of this assembly process revealed that highly dispersed VGMs of 60-90 nm diameter first fuse to form larger vesicles of 200-300 nm diameter that are clustered together. These vesicles then fuse to form tubular elements and short cisternae, which finally assemble into stacks of cisternae. We now provide evidence that the sequential stack formation from VGMs reflects two distinct fusion processes: the first event is N-ethyl-maleimide (NEM)-sensitive factor (NSF) dependent, and the second fusion event requires an NSF-like NEM-sensitive ATPase called p97. Interestingly, while the earliest steps in stack formation share some similarities with events catalyzing fusion of transport vesicles to its target membrane, neither GTP gamma S nor Rab-GDI, inhibitors of vesicular protein traffic, inhibit stack formation.