Palliative Care Always: Hepatology-Virtual Primary Palliative Care Training for Hepatologists.

Palliative care (PC) benefits patients with serious illness including end-stage liver disease (ESLD). As part of a cluster randomized trial, hepatologists were trained to deliver primary palliative care to patients with ESLD using an online course, Palliative Care Always: Hepatology (PCA:Hep). Here we present a multimethod formative evaluation (feasibility, knowledge acquisition, self-efficacy, and practice patterns) of PCA:Hep. Feasibility was measured by completion of coursework and achieving a course grade of >80%. Knowledge acquisition was measured through assessments before and throughout the course. Pre/post-course surveys were conducted to determine self-efficacy and practice patterns. The hepatologists (n = 39) enrolled in a 12-week online course and spent 1-3 hours on the course weekly. The course was determined to be feasible as 97% successfully completed the course and 100% passed. The course was acceptable to participants; 91.7 % reported a positive course experience and satisfaction with knowledge gained (91.6%). The pre/post knowledge assessment showed an improvement of 6.0% (pre 85.9% to post 91.9%, 95% CI [2.8, 9.2], P = 0.001). Self-efficacy increased significantly (P < 0.001) in psychological symptom management, hospice, and psychosocial support. A year after training, over 80% of the hepatologists reported integrating a variety of PC skills into routine patient care. Conclusion: PCA:Hep is feasible, acceptable, and improves learner knowledge and confidence in palliative care skills. This is a viable method to teach primary PC skills to specialists caring for patients with ESLD.

Symbiont population control by host-symbiont metabolic interaction in Symbiodiniaceae-cnidarian associations.

In cnidarian-Symbiodiniaceae symbioses, algal endosymbiont population control within the host is needed to sustain a symbiotic relationship. However, the molecular mechanisms that underlie such population control are unclear. Here we show that a cnidarian host uses nitrogen limitation as a primary mechanism to control endosymbiont populations. Nitrogen acquisition and assimilation transcripts become elevated in symbiotic Breviolum minutum algae as they reach high-densities within the sea anemone host Exaiptasia pallida. These same transcripts increase in free-living algae deprived of nitrogen. Symbiotic algae also have an elevated carbon-to-nitrogen ratio and shift metabolism towards scavenging nitrogen from purines relative to free-living algae. Exaiptasia glutamine synthetase and glutamate synthase transcripts concomitantly increase with the algal endosymbiont population, suggesting an increased ability of the host to assimilate ammonium. These results suggest algal growth and replication in hospite is controlled by access to nitrogen, which becomes limiting for the algae as their population within the host increases.

Rapid, Precise, and Accurate Counts of Symbiodinium Cells Using the Guava Flow Cytometer, and a Comparison to Other Methods.

In studies of both the establishment and breakdown of cnidarian-dinoflagellate symbiosis, it is often necessary to determine the number of Symbiodinium cells relative to the quantity of host tissue. Ideally, the methods used should be rapid, precise, and accurate. In this study, we systematically evaluated methods for sample preparation and storage and the counting of algal cells using the hemocytometer, a custom image-analysis program for automated counting of the fluorescent algal cells, the Coulter Counter, or the Millipore Guava flow-cytometer. We found that although other methods may have value in particular applications, for most purposes, the Guava flow cytometer provided by far the best combination of precision, accuracy, and efficient use of investigator time (due to the instrument's automated sample handling), while also allowing counts of algal numbers over a wide range and in small volumes of tissue homogenate. We also found that either of two assays of total homogenate protein provided a precise and seemingly accurate basis for normalization of algal counts to the total amount of holobiont tissue.

Coral bleaching independent of photosynthetic activity.

The global decline of reef-building corals is due in part to the loss of algal symbionts, or "bleaching," during the increasingly frequent periods of high seawater temperatures. During bleaching, endosymbiotic dinoflagellate algae (Symbiodinium spp.) either are lost from the animal tissue or lose their photosynthetic pigments, resulting in host mortality if the Symbiodinium populations fail to recover. The >1,000 studies of the causes of heat-induced bleaching have focused overwhelmingly on the consequences of damage to algal photosynthetic processes, and the prevailing model for bleaching invokes a light-dependent generation of toxic reactive oxygen species (ROS) by heat-damaged chloroplasts as the primary trigger. However, the precise mechanisms of bleaching remain unknown, and there is evidence for involvement of multiple cellular processes. In this study, we asked the simple question of whether bleaching can be triggered by heat in the dark, in the absence of photosynthetically derived ROS. We used both the sea anemone model system Aiptasia and several species of reef-building corals to demonstrate that symbiont loss can occur rapidly during heat stress in complete darkness. Furthermore, we observed damage to the photosynthetic apparatus under these conditions in both Aiptasia endosymbionts and cultured Symbiodinium. These results do not directly contradict the view that light-stimulated ROS production is important in bleaching, but they do show that there must be another pathway leading to bleaching. Elucidation of this pathway should help to clarify bleaching mechanisms under the more usual conditions of heat stress in the light.

Isolation of clonal axenic strains of the symbiotic dinoflagellate Symbiodinium and their growth and host specificity(1).

The cnidarian-dinoflagellate mutualism is integral to the survival of the coral-reef ecosystem. Despite the enormous ecological and economic importance of corals, their cellular and molecular biology and the ways in which they respond to environmental change are still poorly understood. We have been developing a proxy system for examining the coral mutualism in which the dinoflagellate symbiont Symbiodinium is introduced into a clonal population of the host Aiptasia, a small sea anemone closely related to corals. To further develop the tools for this system, we generated five clonal, axenic strains of Symbiodinium and verified the lack of contaminants by growth on rich medium, microscopic examination, and PCR analysis. These strains were assigned to clades A (two strains), B, E, and F based on their chloroplast 23S rDNA sequences. Growth studies in liquid cultures showed that the clade B strain and one of the clade A strains were able to grow photoautotrophically (in light with no fixed carbon), mixotrophically (in light with fixed carbon), or heterotrophically (in dark with fixed carbon). The clade E strain, thought to be free-living, was able to grow photoautotrophically but not heterotrophically. Infection of an aposymbiotic Aiptasia host with the axenic strains showed consistent patterns of specificity, with only the clade B and one of the clade A strains able to successfully establish symbiosis. Overall, the Aiptasia-Symbiodinium association represents an important model system for dissecting aspects of the physiology and cellular and molecular biology of cnidarian-dinoflagellate mutualism and exploring issues that bear directly on coral bleaching.

Characterization of calcium- and integrin-binding protein 1 (CIB1) knockout platelets: potential compensation by CIB family members.

Platelet aggregation requires activation of the alphaIIbbeta3 integrin, an event regulated by the integrin cytoplasmic tails. CIB1 binds to the cytoplasmic tail of the integrin alphaIIb subunit. Previous over-expression and knockdown studies in murine megakaryocytes demonstrated that CIB1 inhibits integrin alphaIIbbeta3 activation. Here we analyzed Cib1(-/-) mice to determine the function of CIB1 in platelets in vitro and in vivo. We found that although these mice had no overt platelet phenotype, mRNA level of CIB1 homolog CIB3 was increased in Cib1(-/-) megakaryocytes. In vitro binding experiments showed that recombinant CIB1, -2 and -3 bound specifically to an alphaIIb cytoplasmic tail peptide. Subsequent protein modeling experiments indicated that CIBs 1-3 each have a highly conserved hydrophobic binding pocket. Therefore, the potential exists for compensation for the loss of CIB1 by these CIB family members, thereby preventing pathologic thrombus formation in Cib1(-/-) mice.

Tickling the tails: cytoplasmic domain proteins that regulate integrin alphaIIbbeta3 activation.

PURPOSE OF REVIEW: Integrin alphaIIbbeta3 activation is essential for platelet aggregation and related hemostatic events. In recent years, intense effort has been put forward to understand the molecular mechanisms regulating platelet integrin alphaIIbbeta3 activation. Here we review the current models of alphaIIbbeta3 activation and highlight the potential regulatory roles of proteins that interact directly with the alphaIIbbeta3 cytoplasmic domains, with emphasis on the alphaIIb cytoplasmic domain binding protein, CIB1. RECENT FINDINGS: Mutational and crystallographic studies reveal the importance of integrin transmembrane and cytoplasmic domains in propagating bidirectional signaling events. Proteins that interact directly with the integrin cytoplasmic domains may play important roles in mediating these signaling events. Of particular interest is the interaction between CIB1 and the alphaIIb tail which may function to negatively regulate alphaIIbbeta3 activation. In addition, a number of CIB1 interacting proteins have been identified, including p21-activated kinase and serum-inducible kinase, which may act in concert with CIB1 to regulate platelet function. SUMMARY: Understanding the molecular mechanisms underlying integrin activation will be important in developing novel therapies to regulate platelet function in cardiovascular disease. Discussion of recent developments in elucidating the mechanism of integrin activation, with particular focus on the platelet integrin alphaIIbbeta3, is provided in this review.

Drosophila APC2 and APC1 play overlapping roles in wingless signaling in the embryo and imaginal discs.

The regulation of signal transduction plays a key role in cell fate choices, and its disregulation contributes to oncogenesis. This duality is exemplified by the tumor suppressor APC. Originally identified for its role in colon tumors, APC family members were subsequently shown to negatively regulate Wnt signaling in both development and disease. The analysis of the normal roles of APC proteins is complicated by the presence of two APC family members in flies and mice. Previous work demonstrated that, in some tissues, single mutations in each gene have no effect, raising the question of whether there is functional overlap between the two APCs or whether APC-independent mechanisms of Wnt regulation exist. We addressed this by eliminating the function of both Drosophila APC genes simultaneously. We find that APC1 and APC2 play overlapping roles in regulating Wingless signaling in the embryonic epidermis and the imaginal discs. Surprisingly, APC1 function in embryos occurs at levels of expression nearly too low to detect. Further, the overlapping functions exist despite striking differences in the intracellular localization of the two APC family members.