Marrow transplantation with or without donor buffy coat cells for 65 transfused aplastic anemia patients

Sixty-five multiply transfused patients with severe aplastic anemia were given cyclophosphamide followed by grafts anemia were given cyclophosphamide followed by grafts from HLA-identical siblings. The effect of the administration of viable donor buffy coat cells following the marrow inoculum was evaluated with regard to graft rejection and survival. Results in 43 patients so treated are presented along with those in 22 concurrent patients given marrow alone. Most patients given buffy coat had positive in vitro tests of sensitization indicating a high risk for graft rejection, while all but one of the patients given marrow alone had negative tests. Thirty of the 43 (70%) patients given marrow and buffy coat are alive between 10 and 61 mo (median 36) after grafting; 4 died after graft rejection and 6 with acute or chronic graft-versus-host disease (GVHD). Eleven of the 22 (50%) patients given marrow alone are alive between 29 and 65 mo (median 52); 7 died after graft rejection and 3 with GVHD. The addition of buffy coat cell infusions to the marrow inoculum reduced the risk of rejection and increased survival in the currently reported transfused patients when compared to patients grafted before 1976. However, there was an increased risk of chronic GVHD. Recipients of marrow from female donors survived slightly better (73%) than recipients of male marrow (58%).     

Ein neuer Fall von schwerem Faktor XIII-Mangel

Zusammenfassung Bei einem SÄugling mit angeborenem homozygoten Faktor XIII-Mangel traten in den ersten Lebensmonaten eine schwere retroperitoneale und eine intracerebrale Blutung mit Ausbildung eines posthÄmorrhagischen Hydrocephalus auf. Mit der Transglutaminationsreaktion und dem Antiserum-Hemmtest war keine Faktor XIII-AktivitÄt me\bar. In der quantitativen Immunelektrophorese nach Laurell war die eigentlich wirksame Untereinheit A nicht nachweisbar, wÄhrend die Konzentration der Untereinheit S auf 47 % der Norm vermindert war. Nach Substitution mit 250 E. Faktor XIII-Konzentrat wurde enzymatisch eine Faktor XIII-AktivitÄt von 23 % gemessen. Die immunologisch bestimmte Konzentration der Untereinheit A entsprach dem Anstieg der Faktor XIII-AktivitÄt, die Konzentration der Untereinheit S nahm um 20 % zu. Im Alter von 8 Monaten wurde durch wiederholte Bestimmungen der Faktor XIII-AktivitÄt über einen Zeitraum von 39 Tagen nach Substitution der Turnover des Fibrinstabilisierenden Faktors durch eingehende Gerinnungsanalysen bestimmt. Die Halbwertszeit berechnete sich auf 4,7 Tage. Unter einer Dauersubstitutionstherapie mit 250 E. Faktor XIII im Abstand von 6 Wochen blieb das Kind blutungsfrei und entwickelte sich normal.     

Early changes in phosphatidylcholine metabolism in human acute promyelocytic leukemia cells stimulated to differentiate by phorbol ester

The HL-60 leukemia cell line derived from a human acute promyelocytic leukemia is stimulated to differentiate into macrophages within 24-28 hr after exposure to the phorbol ester, 12-O-tetradecanoylphorbol-13- acetate (TPA). We studied early alterations (within 90 min of exposure to TPA) in phosphatidylcholine metabolism in HL-60 cells and found that phosphatidylcholine synthesis by methylation is phosphatidylethanolamine was inhibited in a dose-dependent fashion. In contrast, synthesis of phosphatidylcholine from endogenous choline was enhanced and correlated inversely with the degree of inhibition of the methylation pathway. Phorbol ester congeners of TPA caused similar alterations in phosphatidylcholine metabolism in direct relationship to their capacity to induce differentiation in HL-60 cells. Perturbation of phosphatidylcholine metabolism is an early membrane even in TPA- induced HL-60 cell differentiation.     

Acute allograft rejection and immunosuppression: influence on endogenous melatonin secretion

Abstract: Melatonin displays a dose‐dependent immunoregulatory effect in vitro and in vivo. Exogenous high‐dose melatonin therapy exerted an immunosuppressive effect, abrogating acute rejection (AR), significantly prolonging transplant survival. Endogenous melatonin secretion, in response to heterotopic rat cardiac allograft transplantation (Tx), was investigated during the AR response and under standardized immunosuppressive maintenance therapy with cyclosporin A (CsA) and rapamycin (RPM). Recipients of syngeneic transplants, and recipients of allogeneic grafts, either untreated or receiving immunosuppressive therapy constituted the experimental groups. Endogenous circadian melatonin levels were measured at 07:00, 19:00, and 24:00 hr, using a novel radioimmunoassay (RIA) procedure, under standardized 12‐hr‐light/dark‐conditions (light off: 19:00 hr; light on: 07:00 hr), before and after Tx. Neither the operative trauma, nor the challenge with a perfused allograft or the AR response influenced endogenous melatonin peak secretion. Immunosuppressive therapy with CsA led to a significant increase in peak secretion, measured for days 7 (212 ± 40.7 pg/mL; P < 0.05), 14 (255 ± 13.9 pg/mL; P < 0.001), and 21 (219 ± 34 pg/mL; P < 0.01) after Tx, as compared with naïve animals (155 ± 25.8 pg/mL). In contrast, treatment with RPM significantly decreased the melatonin peak post‐Tx up to day 7 (87 ± 25.2 pg/mL; P < 0.001), compared with naïve animals (155 ± 25.8 pg/mL). These findings imply a robust nature of the endogenous circadian melatonin secretion kinetics, even against the background of profound allogeneic stimuli. Immunosuppressive maintenance therapy with CsA and RPM modulated early melatonin secretion, indicating a specific secondary action of these drugs. Further studies are necessary to disclose the long‐term effect of immunosuppressive therapy on circadian melatonin secretion in transplant recipients.     

Dendritic cell homeostasis is maintained by nonhematopoietic and T‐cell‐produced Flt3‐ligand in steady state and during immune responses

Lymphoid‐tissue dendritic cells (DCs) are short‐lived and need to be continuously replenished from bone marrow‐derived DC progenitor cells. Fms‐related tyrosine kinase 3 is expressed during cellular development from hematopoietic progenitors to lymphoid‐tissue DCs. Fms‐related tyrosine kinase 3 ligand (Flt3L) is an essential, nonredundant cytokine for DC progenitor to lymphoid tissue DC differentiation and maintenance. However, which cells contribute to Flt3L production and how Flt3L cytokine levels are regulated in steady state and during immune reactions remains to be determined. Here we demonstrate that besides nonhematopoietic cells, WT T cells produce Flt3L and contribute to the generation of both classical DCs (cDCs) and plasmacytoid DCs in Flt3L^?/? mice. Upon stimulation in vitro, CD4⁺ T cells produce more Flt3L than CD8⁺ T cells. Moreover, in vivo stimulation of naïve OT‐II CD4⁺ T cells with OVA leads to increase of pre‐cDCs and cDCs in draining lymph nodes of Flt3L^?/? mice in a partially Flt3L‐dependent manner. Thus, Flt3L‐mediated lymphoid tissue DC homeostasis is regulated by steady‐state T cells as well as by proliferative T cells, fostering local development of lymphoid organ resident DCs.     

Exploring the utility of whole‐exome sequencing as a diagnostic tool in a child with atypical episodic muscle weakness

The advent of whole‐exome next‐generation sequencing (WES) has been pivotal for the molecular characterization of Mendelian disease; however, the clinical applicability of WES has remained relatively unexplored. We describe our exploration of WES as a diagnostic tool in a 3½‐year old female patient with a 2‐year history of episodic muscle weakness and paroxysmal dystonia who presented following a previous extensive but unrevealing diagnostic work‐up. WES was performed on the proband and her two parents. Parental exome data was used to filter potential de novo genomic events in the proband and suspected variants were confirmed using di‐deoxy sequencing. WES revealed a de novo non‐synonymous mutation in exon 21 of the calcium channel gene CACNA1S that has been previously reported in a single patient as a rare cause of atypical hypokalemic periodic paralysis. This was unexpected, as the proband's original differential diagnosis had included hypokalemic periodic paralysis, but clinical and laboratory features were equivocal, and standard clinical molecular testing for hypokalemic periodic paralysis and related disorders was negative. This report highlights the potential diagnostic utility of WES in clinical practice, with implications for the approach to similar diagnostic dilemmas in the future.     

Identifying misbonded atoms in the 2019 CoRE metal–organic framework database

Databases of experimentally-derived metal–organic framework (MOF) crystal structures are useful for large-scale computational screening to identify which MOFs are best-suited for particular applications. However, these crystal structures must be cleaned to identify and/or correct various artifacts. The recently published 2019 CoRE MOF database (Chung et al., J. Chem. Eng. Data, 2019, 64, 5985–5998) reported thousands of experimentally-derived crystal structures that were partially cleaned to remove solvent molecules, to identify hundreds of disordered structures (approximately thirty of those were corrected), and to manually correct approximately 100 structures (e.g., adding missing hydrogen atoms). Herein, further cleaning of the 2019 CoRE MOF database is performed to identify structures with misbonded or isolated atoms: (i) structures containing an isolated atom, (ii) structures containing atoms too close together (i.e., overlapping atoms), (iii) structures containing a misplaced hydrogen atom, (iv) structures containing an under-bonded carbon atom (which might be caused by missing hydrogen atoms), and (v) structures containing an over-bonded carbon atom. This study should not be viewed as the final cleaning of this database, but rather as progress along the way towards the goal of someday achieving a completely cleaned set of experimentally-derived MOF crystal structures. We performed atom typing for all of the accepted structures to identify those structures that can be parameterized by previously reported forcefield precursors (Chen and Manz, RSC Adv., 2019, 9, 36492–36507). We report several forcefield precursors (e.g., net atomic charges, atom-in-material polarizabilities, atom-in-material dispersion coefficients, electron cloud parameters, etc.) for more than five thousand MOFs in the 2019 CoRE MOF database.

The 2019 CoRE MOF database was cleaned by identifying structures containing isolated atoms, overlapping atoms, misplaced hydrogens, and under/over-bonded carbons.