Social media and organ donation: Ethically navigating the next frontier.

As the organ shortage continues to grow, the creation of social media communities by transplant hospitals and the public is rapidly expanding to increase the number of living donors. Social media communities are arranged in myriad ways and without standardization, raising concerns about transplant candidates' and potential donors' autonomy and quality of care. Social media communities magnify and modify extant ethical issues in deceased and living donation related to privacy, confidentiality, professionalism, and informed consent, and increase the potential for undue influence and coercion for potential donors and transplant candidates. Currently, no national ethical guidelines have been developed in the United States regarding the use of social media to foster organ transplantation. We provide an ethical framework to guide transplant stakeholders in using social media for public and patient communication about transplantation and living donation, and offer recommendations for transplant clinical practice and future research.

Molecular classifiers for acute kidney transplant rejection in peripheral blood by whole genome gene expression profiling.

There are no minimally invasive diagnostic metrics for acute kidney transplant rejection (AR), especially in the setting of the common confounding diagnosis, acute dysfunction with no rejection (ADNR). Thus, though kidney transplant biopsies remain the gold standard, they are invasive, have substantial risks, sampling error issues and significant costs and are not suitable for serial monitoring. Global gene expression profiles of 148 peripheral blood samples from transplant patients with excellent function and normal histology (TX; n = 46), AR (n = 63) and ADNR (n = 39), from two independent cohorts were analyzed with DNA microarrays. We applied a new normalization tool, frozen robust multi-array analysis, particularly suitable for clinical diagnostics, multiple prediction tools to discover, refine and validate robust molecular classifiers and we tested a novel one-by-one analysis strategy to model the real clinical application of this test. Multiple three-way classifier tools identified 200 highest value probesets with sensitivity, specificity, positive predictive value, negative predictive value and area under the curve for the validation cohort ranging from 82% to 100%, 76% to 95%, 76% to 95%, 79% to 100%, 84% to 100% and 0.817 to 0.968, respectively. We conclude that peripheral blood gene expression profiling can be used as a minimally invasive tool to accurately reveal TX, AR and ADNR in the setting of acute kidney transplant dysfunction.

Postoperative ad lib feeding for hypertrophic pyloric stenosis.

PURPOSE: The aim of this study was to compare three methods of postoperative feeding after pyloromyotomy for hypertrophic pyloric stenosis (HPS). METHODS: The authors reviewed retrospectively the charts of 308 patients who underwent pyloromyotomy for HPS from 1984 to 1997. Nineteen patients had prolonged hospitalization for other reasons and were excluded from the study, leaving 289 patients for analysis. All procedures were performed by a single group of pediatric surgeons. The individual preferences of these surgeons resulted in three different feeding schedules: R, strictly regimented (>12 hours nothing by mouth, then incremental feeding over > or =24 hours), I, intermediate (>8 hours nothing by mouth, then incremental feeding over <24 hours), or A, ad lib (< or =4 hours nothing by mouth, with or without a single small feeding, then ad lib feedings). RESULTS: Of the 289 patients, 248 (80.5%) were boys. The average age of the patients was 5.64 weeks (range, 1 to 21 weeks). A total of 265 of 289 (92%) were full term. Thirty-nine of 289 (13.5%) had a family history positive for pyloric stenosis. A total of 104 of 289 (36%) were first-born infants, 89 of 289 (31%) were second born. The diagnosis of pyloric stenosis was made by a combination of physical examination findings and diagnostic image for most patients. An "olive" was palpated in 60.6% of the patients. Sixty percent (60.4%) of patients had an upper gastrointestinal series performed, and 42.5% were examined by ultrasonography. Overall, 53% of the patients had postoperative emesis. Only 3.5% had emesis that persisted greater than 48 hours after surgery. Patients fed ad lib after pyloromyotomy had slightly more emesis (2.2 A v. 1.2 R, and 0.7 I episodes, P = .002), but tolerated full feedings sooner than patients fed with a regimented or intermediate schedule. No patient required additional therapy or readmission after tolerating two consecutive full feedings, suggesting that this might be a suitable discharge criterion for most patients with HPS.

Virus and host-specific adaptations in the BL1 and BR1 genes of bipartite geminiviruses.

The host range of individual geminiviruses may be quite narrow, and closely related viruses can exhibit distinct host adaptations. Two such bipartite geminiviruses are bean golden mosaic virus (GBMV) and tomato golden mosaic virus (TGMV). In both, the BL1 and BR1 genes are required for the spread of virus infection in plants. We have investigated the contributions of BL1 and BR1 to host-specific phenotypes of BGMV and TGMV by constructing hybrid viruses in which these coding regions were exchanged. Hybrids were assayed on bean, a good host for BGMV, and Nicotiana benthamiana, a good host for TGMV. A BGMV hybrid having TGMV BL1 and BR1 efficiently infected beans, but elicited attenuated symptoms. In N. benthamiana, this hybrid had slightly increased virulence and DNA accumulation relative to wild-type BGMV. A TGMV hybrid having BGMV BL1 and BR1 was virulent in N. benthamiana, but elicited attenuated symptoms. However, this hybrid exhibited no gain of function in beans relative to wild-type TGMV. Hybrid viruses with TGMV BL1 and BGMV BR1 had severely defective phenotypes in either viral or host background. Although exchanging BL1 and BR1 between BGMV and TGMV did not change host range, some host adaptation of these genes is suggested. However, virus-specific compatibility between BL1 and BR1 is of more importance for viability. Thus, these gene products may act in concert to potentiate virus movement.

Complementable and noncomplementable host adaptation defects in bipartite geminiviruses.

Members of the geminvirus group of plant viruses collectively infect a broad spectrum of species. Individual viruses which are genetically very similar may nevertheless have distinct host ranges. Two such geminiviruses are tomato golden mosaic virus (TGMV) and been golden mosaic virus (BGMV), for which common hosts have not previously been reported. Each virus has two genome components, designated A and B. The A component is capable of autonomous replication and encapsidation, whereas the B component provides viral functions required for the spread of infection in plants. To investigate the basis for the distinctive host ranges of BGMV and TGMV, we have introduced plasmids containing cloned viral genome components into Nicotiana benthamiana, a good host for TGMV, and bean, Phaseolus vulgaris, a good host for BGMV. We found that TGMV has a low specific infectivity for bean and is virulent, whereas BGMV has a high specific infectivity for N. benthamiana, but infections are asymptomatic and viral DNA accumulation is low. To investigate which viral functions were defective in the poor host in each case, we attempted to complement them by co-inoculation with the well-adapted virus. After inoculation of beans with both viruses, only BGMV was detected. Thus, TGMV exhibits a noncomplementable host adaptation defect in beans. This suggests that the defect has a cis-acting or virus-specific trans-acting genetic basis. In contrast, the BGMV phenotype of low DNA accumulation in N. benthamiana was partially complemented by TGMV A alone and complemented further by the complete TGMV genome. This suggests that a virus nonspecific, trans-acting factor encoded by the BGMV A component is poorly adapted to N. benthamiana. The results of this study indicate that bipartite geminivirus host range may be limited by defective virus-host interactions of more than one kind.

Graft-rejection and toxicity following bone marrow transplantation in relation to busulfan pharmacokinetics.

We have determined the relationships between busulfan average concentration at steady-state and (1) rejection of graft, and (2) regimen-related toxicity, and have evaluated the dependence of busulfan clearance/F on body size and age. Patients received 16-30 mg/kg of busulfan followed by cyclophosphamide in doses of 120, 150, 174, or 200 mg/kg or 8 g/m2 in preparation for autologous, syngeneic or allogeneic grafts varying in compatibility from HLA-matched siblings to HLA-partially-matched unrelated donors. In a multivariate Cox time-to-rejection analysis, only busulfan concentration remained a significant determinant of rejection, P = 0.0154. An average concentration of busulfan at steady-state of at least 200 ng/ml was needed to avoid rejection of a matched-sibling graft, while 600 ng/ml was needed to avoid rejection of HLA-partially-matched related or HLA-matched unrelated donor grafts. The toxicity of the cytoreductive regimen correlated with busulfan average concentration at steady-state (rs = 0.717). Busulfan clearance/F expressed relative to body weight, ideal body weight or surface area declined with age during the first decade of life. Over the entire span of age, the coefficient of variation in clearance/F for all ages was similar when clearance/F was expressed in absolute terms (ml/min) and when adjusted for body surface area; the coefficient of variation was greater for clearance/F when expressed relative to total or ideal body weight. We conclude that busulfan concentration in plasma is an important determinant of graft survival and regimen-related toxicity, and that the variability of busulfan pharmacokinetics with age precludes the use of a fixed dose for all ages and indications.

Geminivirus replication origins have a modular organization.

Tomato golden mosaic virus (TGMV) and bean golden mosaic virus (BGMV) are closely related geminiviruses with bipartite genomes. The A and B DNA components of each virus have cis-acting sequences necessary for replication, and their A components encode trans-acting factors are required for this process. We showed that virus-specific interactions between the cis- and trans-acting functions are required for TGMV and BGMV replication in tobacco protoplasts. We also demonstrated that, similar to the essential TGMV AL1 replication protein, BGMV AL1 binds specifically to its origin in vitro and that neither TGMV nor BGMV AL1 proteins bind to the heterologous origin. The in vitro AL1 binding specificities of the B components were exchanged by site-directed mutagenesis, but the resulting mutants were not replicated by either A component. These results showed that the high-affinity AL1 binding site is necessary but not sufficient for virus-specific origin activity in vivo. Geminivirus genomes also contain a stem-loop sequence that is required for origin function. A BGMV B mutant with the TGMV stem-loop sequence was replicated by BGMV A, indicating that BGMV AL1 does not discriminate between the two sequences. A BGMV B double mutant, with the TGMV AL1 binding site and stem-loop sequences, was not replicated by either A component, indicating that an additional element in the TGMV origin is required for productive interaction with TGMV AL1. These results suggested that geminivirus replication origins are composed of at least three functional modules: (1) a putative stem-loop structure that is required for replication but does not contribute to virus-specific recognition of the origin, (2) a specific high-affinity binding site for the AL1 protein, and (3) at least one additional element that contributes to specific origin recognition by viral trans-acting factors.