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Background: Among heart transplant (HT) recipients who develop advanced graft dysfunction, cardiac re‐transplantation may be considered. A smaller subset of patients will experience failure of their second allograft and undergo repeat re‐transplantation. Outcomes among these individuals are not well‐described. Methods: Adult and pediatric patients in the United Network for Organ Sharing (UNOS) registry who received HT between January 1, 1990 and December 31, 2020 were included. Results: Between 1990 and 2020, 90 individuals received a third HT and three underwent a fourth HT. Recipients were younger than those undergoing primary HT (mean age 32 years). Third HT was associated with significantly higher unadjusted rates of 1‐year mortality (18% for third HT vs. 13% for second HT vs. 9% for primary HT, p <.001) and 10‐year mortality (59% for third HT vs. 42% for second HT vs. 37% for primary HT, p <.001). Mortality was highest amongst recipients aged >60 years and those re‐transplanted for acute graft failure. Long‐term rates of CAV, rejection, chronic dialysis, and hospitalization for infection were also higher. Conclusions: Third HT is associated with higher morbidity and mortality than primary HT. Further consensus is needed regarding appropriate organ stewardship for this unique subgroup. [ABSTRACT FROM AUTHOR]

Donor‐specific antibodies (DSA) are associated with antibody‐mediated rejection (AMR) and poor patient survival. In heart transplant, the efficacy of intermittent intravenous immunoglobulin (IVIg) in reducing de novo DSA levels and treating AMR has not been characterized. We retrospectively studied a cohort of 19 patients receiving intermittent IVIg for elevated DSA and examined changes in DSA levels and graft function. Intermittent IVIg infusions were generally safe and well tolerated. Overall, 23 of 62 total DSA (37%) were undetectable after treatment, 21 DSA (34%) had MFI decrease by more than 25%, and 18 (29%) had MFI decrease by less than 25% or increase. The average change in MFI was ‐51% ± 71% (P <.001). Despite reductions in DSA, among the six patients (32%) with biopsy‐confirmed AMR, left ventricular ejection fraction (LVEF) decreased in five (83%) and cardiac index (CI) decreased in three (50%). Conversely, LVEF increased in 91% and CI increased in 70% of biopsy‐negative patients. All six AMR patients were readmitted during treatment, four for confirmed or suspected rejection. IVIg infusions may stabilize the allograft in patients with elevated DSA and negative biopsies, but once AMR has developed does not appear to improve allograft function despite decreasing DSA levels. [ABSTRACT FROM AUTHOR]

Abstract: The expression of CSDC9 encoding S-adenosylmethionine decarboxylase (SAMDC) is developmentally and spatially regulated in carnation. To examine the regulation of the SAMDC gene, we analyzed the spatial expression of CSDC9 with a 5′-flanking β-glucuronidase fusion in transgenic tobacco plants. GUS was strongly expressed in flower, pollen, stem and vein of cotyledons. Expression in both anther and stigma was under developmental control; analysis of a series of mutants with deletions of the 5′-flanking region demonstrated differential activation in petal, anther, stigma and pollen grains. All the major cis-regulatory elements required for pollen-specific transcription were located in the upstream region between −273 and −158. This region contains four putative elements related to gibberellin induction (pyrimidine boxes, TTTTTTCC and CCTTTT) and pollen-specific expression (GTGA and AGAAA). In addition, the first 5′-leader intron was necessary for tissue-specific expression. [Copyright &y& Elsevier]

We cloned a cDNA encoding caltractin, a 20 kDa calcium-binding protein, from Dunaliella salina (DSCALT). The Ca2+-bound mobility shift detected in Chlamydomonas caltractin was hardly detectable in DSCALT. Also, some differences were found in the electrophoretic mobility between the native DSCALT and the bacterial-expressed DSCALT. This difference may have resulted from the posttranslational modification. Immunoblot analysis revealed that this protein might be localized mainly in the basal body complex, the major microtubule organizing center (MTOC) in D. salina and the functional homologue of the centrosome in the animal cell. [ABSTRACT FROM AUTHOR]

The role of Ca2+ and protein phosphorylation in the transduction of the ethylene signal resulting in induction of 1-aminocyclopropane-l-carboxylic acid (ACC) oxidase has been studied in peas (Pisum sativum L.) by a pharmacological approach. 2,5-Norbornadiene (NBD) and aminoethoxy-vinylglycine (AVG) reduced the basal level of ACC oxidase transcript and its enzyme activity. Only NBD was shown to inhibit the ethylene response, the accumulation of ACC oxidase transcript and the stimulation of its enzyme activity. Ethylene influenced 45Ca2+ influx into the segment tissues from pea epicotyls, and ethylene glycol-bis(rβ-aminoethyl ether)N,N,N'N'-tetraacetic acid (EGTA), a Ca2+ chelator, inhibited the ethylene response. Ca2+ depletion by pre-treatment with EGTA also blocked the ethylene response, which almost completely recovered when Ca2+ was added exogenously after Ca2+ depletion. Ca2+ channel blockers, verapamil, and LaCl3, used to certify the role of extracellular Ca2+, all inhibited the ethylene response. A protein kinase inhibitor, 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7), and protein phosphatase inhibitors, vanadate and okadaic acid, also inhibited the ethylene response. The results of the present study suggest that Ca2+ influx from the extracellular space, protein phosphorylation, and dephosphorylation are required for the induction of ACC oxidase by ethylene. [ABSTRACT FROM AUTHOR]

Arginine decarboxylase (EC 4.1.1.19) was purified from soybean, Glycine max, hypocotyls by a procedure which includes ammonium sulfate fractionation, acetone precipitation, gel filtration chromatography, and affinity chromatography. Using this procedure, ADC was purified to one band in non-denaturing PAGE. The purified ADC has an Mr of 240 kDa based on gel filtration chromatography and is a trimer of identical subunits which has an estimated Mr of 74 kDa based on SDS-PAGE. ADC is active between 30 and 50°C and has a Km value of 46.1 μM. ADC is very sensitive to agmatine or putrescine but not to spermidine or spermine. In the presence of 0.5 mM agmatine (or putrescine), the enzyme activity was inhibited by 70%. However, at the same concentration of spermidine (or spermine), the enzyme activity was inhibited by only 10–20%. [ABSTRACT FROM AUTHOR]

Arginine decarboxylase (ADC) is one of the key enzymes in the biosynthesis of putrescine in plants. The regulation of its activity depends on the physiological condition, developmental stage, and type of tissue. We have cloned ADC cDNA from soybean (Glycine max) hypocotyls to understand the regulation mechanisms of this enzyme activity. Using the cDNA clone, we examined the relationship between changes in the ADC activity and the level of ADC mRNA during development, in different tissues, and upon acid stress. The ADC activity began to increase 2 d after initiation of germination, reached a peak at the 5th d, and then declined. This change in the enzyme activity was preceded by similar changes in the level of the mRNA. The ADC activity was expressed tissue-specifically; this expression was well corelated with the mRNA content of the respective tissues. Incubation of the 5-d-old hypocotyls in pH 3 potassium phosphate solution caused a rapid increase in ADC activity. Within 2 h of acid treatment, the ADC activity increased more than threefold. This increase was also preceded by a corresponding increase in the mRNA content and was also regulated tissue-specifically. These results suggest that the change in the content of ADC mRNA has an important role in the regulation of the enzyme activity during early development, in different tissues, and upon acid stress. [ABSTRACT FROM AUTHOR]

Three full length 1-aminocyclopropane-l-carboxylate (ACC) oxidase cDNA clones (pNG-ACOl, 1,254 bp; pNG-ACO2,1,198 bp; and pNG-ACO3,1,053 bp) were isolated from the TMV-treated leaf cDNA library of Nicotiana glutinosa plant. They share a high degree of sequence identity (78–81%) throughout the coding regions but are divergent within the 3′-untranslated regions. The gene-specific probes were prepared using these regions to investigate the differential expression of the ACC oxidase gene family in various organs and in response to a multitude of biotic and abiotic stresses in N. glutinosa plants. All three genes were transcriptionally active displaying unique patterns of expression. Both the pNG-ACOl and pNG-ACO3 transcripts highly accumulated during the senescence of leaves, while the pNG-ACO2 mRNA was constitutively present. In addition, the NG-ACO1 and NG-ACO3 transcripts were predominantly found in roots whereas the NG-ACO2 mRNA was mainly in stems. Upon TMV infection, both NG-ACO1 and NG-ACO3 were markedly induced, but in mock treatment which has an effect of mild wounding, only the NG-ACO3 gene was induced. Furthermore, salicylic acid and CuSO4 treatments of leaves increased the level of NG-ACO1 and NG-ACO3 transcripts, while they did not affect the NG-ACO2 gene expression. Results showed that both the NG-ACO1 and NG-ACO3 genes were highly inducible by ethylene and methyl jasmonate treatments, with NG-ACO3 being more responsive. By contrast, NG-ACO2 did not respond to these growth regulators. Thus, it appears that there are two groups of ACC oxidase transcripts expressed in leaf tissue of N. glutinosa, either stress-induced or constitutive. The possible molecular mechanism of differential regulation of ACC oxidase gene expression and its physiological significance are discussed. [ABSTRACT FROM AUTHOR]

The effect of a synthetic cytokinin, 6-benzylaminopurine (BAP), on gene expression of Rho1Ps in shoot apex segments of garden pea was examined by Northern blot hybridization using32P-labelled 560 bp partial Rho1Ps cDNA fragment as the probe. The application of 1012 M BAP, the lowest concentration tested, for 24h to the segments strongly activated the synthesis of Rho1Ps transcripts as much as 7 times compared with those in BAP-untreated segments. In addition, the Rho1Ps transcripts synthesis was enhanced by BAP in a concentration dependent manner, suggesting that BAP is concretly involved in the Rho1Ps gene expression in the segments. A time course analysis of BAP on Rho1Ps gene expression exhibited that BAP was closely related not only to the Rho1Ps transcripts synthesis but also to the degradation of Rho1Ps transcripts. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the clinical implications of adjunctive molecular gene expression analysis (MMDx ) of biopsy specimens in heart transplant (HT ) recipients with suspected rejection., Introduction: Histopathological evaluation remains the standard method for rejection diagnosis in HT. However, the wide interobserver variability combined with a relatively common incidence of "biopsy-negative" rejection has raised concerns about the likelihood of false-negative results. MMDx, which uses gene expression to detect early signs of rejection, is a promising test to further refine the assessment of HT rejection., Methods: Single-center prospective study of 418 consecutive for-cause endomyocardial biopsies performed between November 2022 and May 2024. Each biopsy was graded based on histology and assessed for rejection patterns using MMDx. MMDx results were deemed positive if borderline or definitive rejection was present. The impact of MMDx results on clinical management was evaluated. Primary outcomes were 1-year survival and graft dysfunction following MMDx-guided clinical management. Secondary outcomes included changes in donor-specific antibodies, MMDx gene transcripts, and donor-derived cell-free DNA (dd-cfDNA) levels., Results: We analyzed 418 molecular samples from 237 unique patients. Histology identified rejection in 32 cases (7.7%), while MMDx identified rejection in 95 cases (22.7%). Notably, in 79 of the 95 cases where MMDx identified rejection, histology results were negative, with the majority of these cases being antibody-mediated rejection (62.1%). Samples with rejection on MMDx were more likely to show a combined elevation of dd-cfDNA and peripheral blood gene expression profiling than those with borderline or negative MMDx results (36.7% vs 28.0% vs 10.3%; p<0.001). MMDx results led to the implementation of specific antirejection protocols or changes in immunosuppression in 20.4% of cases, and in 73.4% of cases where histology was negative and MMDx showed rejection. 1-year survival was better in the positive MMDx group where clinical management was guided by MMDx results (87.0% vs 78.6%; log rank p=0.0017)., Conclusions: In our cohort, MMDx results more frequently indicated rejection than histology, often leading to the initiation of antirejection treatment. Intervention guided by positive MMDx results was associated with improved outcomes.