Surface stratification determines the interfacial water structure of simple electrolyte solutions

The distribution of ions at the air/water interface plays a decisive role in many natural processes. Several studies have reported that larger ions tend to be surface-active, implying ions are located on top of the water surface, thereby inducing electric fields that determine the interfacial water structure. Here we challenge this view by combining surface-specific heterodyne-detected vibrational sum-frequency generation with neural network-assisted ab initio molecular dynamics simulations. Our results show that ions in typical electrolyte solutions are, in fact, located in a subsurface region, leading to a stratification of such interfaces into two distinctive water layers. The outermost surface is ion-depleted, and the subsurface layer is ion-enriched. This surface stratification is a key element in explaining the ion-induced water reorganization at the outermost air/water interface.

Depth-profiling alkyl chain order in unsaturated lipid monolayers on water

Unsaturated lipids with C=C groups in their alkyl chains are widely present in the cell membrane and food. The C=C groups alter the lipid packing density, membrane stability, and persistence against lipid oxidation. Yet, molecular-level insights into the structure of the unsaturated lipids remain scarce. Here, we probe the molecular structure and organization of monolayers of unsaturated lipids on the water surface using heterodyne-detected sum-frequency generation (HD-SFG) spectroscopy. We vary the location of the C=C in the alkyl chain and find that at high lipid density, the location of the C=C group affects neither the interfacial water organization nor the tail of the alkyl chain. Based on this observation, we use the C=C stretch HD-SFG response to depth-profile the alkyl chain conformation of the unsaturated lipid. We find that the first 1/3 of carbon atoms from the headgroup are relatively rigid, oriented perpendicular to the surface. In contrast, the remaining carbon atoms can be approximated as free rotators, introducing the disordering of the alkyl chains.

Spontaneous Appearance of Triiodide Covering the Topmost Layer of the Iodide Solution Interface Without Photo-Oxidation

Ions containing iodine atoms at the vapor-aqueous solution interfaces critically affect aerosol growth and atmospheric chemistry due to their complex chemical nature and multivalency. While the surface propensity of iodide ions has been intensely discussed in the context of the Hofmeister series, the stability of various ions containing iodine atoms at the vapor-water interface has been debated. Here, we combine surface-specific sum-frequency generation (SFG) vibrational spectroscopy with ab initio molecular dynamics simulations to examine the extent to which iodide ions cover the aqueous surface. The SFG probe of the free O-D stretch mode of heavy water indicates that the free O-D group density decreases drastically at the interface when the bulk NaI concentration exceeds ∼2 M. The decrease in the free O-D group density is attributed to the spontaneous appearance of triiodide that covers the topmost interface rather than to the surface adsorption of iodide. This finding demonstrates that iodide is not surface-active, yet the highly surface-active triiodide is generated spontaneously at the water-air interface, even under dark and oxygen-free conditions. Our study provides an important first step toward clarifying iodine chemistry and pathways for aerosol formation.

Bulklike Vibrational Coupling of Surface Water Revealed by Sum-Frequency Generation Spectroscopy

Vibrational coupling between interfacial water molecules is important for energy dissipation after on-water chemistry, yet intensely debated. Here, we quantify the interfacial vibrational coupling strength through the linewidth of surface-specific vibrational spectra of the water's O─H (O─D) stretch region for neat H_{2}O/D_{2}O and their isotopic mixtures. The local-field-effect-corrected experimental SFG spectra reveal that the vibrational coupling between hydrogen-bonded interfacial water O─H groups is comparable to that in bulk water, despite the effective density reduction at the interface.

Does the Sum-Frequency Generation Signal of Aromatic C-H Vibrations Reflect Molecular Orientation?

Organic molecules with aromatic groups at the aqueous interfaces play a central role in atmospheric chemistry, green chemistry, and on-water synthesis. Insights into the organization of interfacial organic molecules can be obtained using surface-specific vibrational sum-frequency generation (SFG) spectroscopy. However, the origin of the aromatic C-H stretching mode peak is unknown, prohibiting us from connecting the SFG signal to the interfacial molecular structure. Here, we explore the origin of the aromatic C-H stretching response by heterodyne-detected SFG (HD-SFG) at the liquid/vapor interface of benzene derivatives and find that, irrespective of the molecular orientation, the sign of the aromatic C-H stretching signals is negative for all the studied solvents. Together with density functional theory (DFT) calculations, we reveal that the interfacial quadrupole contribution dominates, even for the symmetry-broken benzene derivatives, although the dipole contribution is non-negligible. We propose a simple evaluation of the molecular orientation based on the aromatic C-H peak area.

True Origin of Amide I Shifts Observed in Protein Spectra Obtained with Sum Frequency Generation Spectroscopy

Accurate determination of protein structure at interfaces is critical for understanding protein interactions, which is directly relevant to a molecular-level understanding of interfacial proteins in biology and medicine. Vibrational sum frequency generation (VSFG) spectroscopy is often used for probing the protein amide I mode, which reports protein structures at interfaces. Observed peak shifts are attributed to conformational changes and often form the foundation of hypotheses explaining protein working mechanisms. Here, we investigate structurally diverse proteins using conventional and heterodyne-detected VSFG (HD-VSFG) spectroscopy as a function of solution pH. We reveal that blue-shifts of the amide I peak observed in conventional VSFG spectra upon lowering the pH are governed by the drastic change of the nonresonant contribution. Our results highlight that connecting changes in conventional VSFG spectra to conformational changes of interfacial proteins can be arbitrary, and that HD-VSFG measurements are required to draw unambiguous conclusions about structural changes in biomolecules.

Surface Potential at Electrolyte/Air Interfaces: A Quantitative Analysis via Sum-Frequency Vibrational Spectroscopy

We conduct a quantitative phase-sensitive sum-frequency vibrational spectroscopic investigation on the air/water interface with various atmospherically relevant ions in water in submolar concentrations. At electrolyte concentrations below 0.1 M, the spectral changes of the OH-stretching resonance induced by ions exhibit no ion specificity and resemble the lineshape of the third-order nonlinear optical susceptibility of bulk water. These findings, along with the result of invariant free OH resonance, indicate that the primary effect of the electric double layer of ions on the interfacial structure arises from the mean-field-induced molecular alignment in a subsurface bulklike hydrogen-bonding network. Analysis of the spectra allows us to determine quantitatively the surface potentials for six electrolyte solutions (MgCl₂, CaCl₂, NH₄Cl, Na₂SO₄, NaNO₃, and NaSCN). Our results agree well with the predictions of Levin's continuum theory, implying fairly small electrostatic correlations for the studied divalent ions.

Ions Speciation at the Water-Air Interface

In typical aqueous systems, including naturally occurring sweet and salt water and tap water, multiple ion species are co-solvated. At the water-air interface, these ions are known to affect the chemical reactivity, aerosol formation, climate, and water odor. Yet, the composition of ions at the water interface has remained enigmatic. Here, using surface-specific heterodyne-detected sum-frequency generation spectroscopy, we quantify the relative surface activity of two co-solvated ions in solution. We find that more hydrophobic ions are speciated to the interface due to the hydrophilic ions. Quantitative analysis shows that the interfacial hydrophobic ion population increases with decreasing interfacial hydrophilic ion population at the interface. Simulations show that the solvation energy difference between the ions and the intrinsic surface propensity of ions determine the extent of an ion's speciation by other ions. This mechanism provides a unified view of the speciation of monatomic and polyatomic ions at electrolyte solution interfaces.

On the Fresnel factor correction of sum-frequency generation spectra of interfacial water

Insights into the microscopic structure of aqueous interfaces are essential for understanding the chemical and physical processes on the water surface, including chemical synthesis, atmospheric chemistry, and events in biomolecular systems. These aqueous interfaces have been probed by heterodyne-detected sum-frequency generation (HD-SFG) spectroscopy. To obtain the molecular response from the measured HD-SFG spectra, one needs to correct the measured ssp spectra for local electromagnetic field effects at the interface due to a spatially varying dielectric function. This so-called Fresnel factor correction can change the inferred response substantially, and different ways of performing this correction lead to different conclusions about the interfacial water response. Here, we compare the simulated and experimental spectra at the air/water interface. We use three previously developed models to compare the experiment with theory: an advanced approach taking into account the detailed inhomogeneous interfacial dielectric profile and the Lorentz and slab models to approximate the interfacial dielectric function. Using the advanced model, we obtain an excellent quantitative agreement between theory and experiment, in both spectral shape and amplitude. Remarkably, we find that for the Fresnel factor correction of the ssp spectra, the Lorentz model for the interfacial dielectric function is equally accurate in the hydrogen (H)-bonded region of the response, while the slab model underestimates this response significantly. The Lorentz model, thus, provides a straightforward method to obtain the molecular response from the measured spectra of aqueous interfaces in the H-bonded region.

Polarization-Dependent Heterodyne-Detected Sum-Frequency Generation Spectroscopy as a Tool to Explore Surface Molecular Orientation and Ångström-Scale Depth Profiling

Sum-frequency generation (SFG) spectroscopy provides a unique optical probe for interfacial molecules with interface-specificity and molecular specificity. SFG measurements can be further carried out at different polarization combinations, but the target of the polarization-dependent SFG is conventionally limited to investigating the molecular orientation. Here, we explore the possibility of polarization-dependent SFG (PD-SFG) measurements with heterodyne detection (HD-PD-SFG). We stress that HD-PD-SFG enables accurate determination of the peak amplitude, a key factor of the PD-SFG data. Subsequently, we outline that HD-PD-SFG can be used not only for estimating the molecular orientation but also for investigating the interfacial dielectric profile and studying the depth profile of molecules. We further illustrate the variety of combined simulation and PD-SFG studies.

Accurate molecular orientation at interfaces determined by multimode polarization-dependent heterodyne-detected sum-frequency generation spectroscopy via multidimensional orientational distribution function

Many essential processes occur at soft interfaces, from chemical reactions on aqueous aerosols in the atmosphere to biochemical recognition and binding at the surface of cell membranes. The spatial arrangement of molecules specifically at these interfaces is crucial for many of such processes. The accurate determination of the interfacial molecular orientation has been challenging due to the low number of molecules at interfaces and the ambiguity of their orientational distribution. Here, we combine phase- and polarization-resolved sum-frequency generation (SFG) spectroscopy to obtain the molecular orientation at the interface. We extend an exponentially decaying orientational distribution to multiple dimensions, which, in conjunction with multiple SFG datasets obtained from the different vibrational modes, allows us to determine the molecular orientation. We apply this new approach to formic acid molecules at the air–water interface. The inferred orientation of formic acid agrees very well with ab initio molecular dynamics data. The phase-resolved SFG multimode analysis scheme using the multidimensional orientational distribution thus provides a universal approach for obtaining the interfacial molecular orientation.

Pediatric hematology/oncology healthcare professional emotional health during COVID-19

Objectives

Little is known about the impact of coronavirus disease 2019 (COVID‐19) on healthcare professional emotional health in pediatric hematology/oncology. Primary objective was to describe anxiety, depression, positive affect, and perceived stress among pediatric hematology/oncology healthcare professionals following a COVID‐19 outbreak. Secondary objectives were to compare these outcomes based on contact with a positive person, and to identify risk factors for worse outcomes.

Materials and methods

We included 272 healthcare professionals working with pediatric hematology/oncology patients. We determined whether respondents had direct or indirect contact with a COVID‐19‐positive individual and then measured outcomes using the Patient‐Reported Outcomes Measurement Information System (PROMIS) depression, anxiety, and positive affect measures, and the Perceived Stress Scale.

Results

Among eligible respondents, 205 agreed to participate (response rate 75%). Sixty‐nine (33.7%) had contact with a COVID‐19‐positive person. PROMIS anxiety, depression, and positive affect scores were similar to the general United States population. Those who had contact with a COVID‐19‐positive individual did not have significantly different outcomes. In multiple regression, non‐physicians had significantly increased anxiety (nurses: p = 0.013), depression (nurses: p = 0.002, pharmacists: p = 0.038, and other profession: p = 0.021), and perceived stress (nurses: p = 0.002 and other profession: p = 0.011) when compared to physicians.

Conclusions

Pediatric hematology/oncology healthcare professionals had similar levels of anxiety, depression, and positive affect as the general population. Contact with a COVID‐19‐positive individual was not significantly associated with outcomes. Non‐physician healthcare professionals had more anxiety, depression, and perceived stress when compared to physicians. These findings may help to develop programs to support healthcare professional resilience.

Disentangling Sum-Frequency Generation Spectra of the Water Bending Mode at Charged Aqueous Interfaces

The origin of the sum-frequency generation (SFG) signal of the water bending mode has been controversially debated in the past decade. Unveiling the origin of the signal is essential, because different assignments lead to different views on the molecular structure of interfacial water. Here, we combine collinear heterodyne-detected SFG spectroscopy at the water-charged lipid interfaces with systematic variation of the salt concentration. The results show that the bending mode response is of a dipolar, rather than a quadrupolar, nature and allows us to disentangle the response of water in the Stern and the diffuse layers. While the diffuse layer response is identical for the oppositely charged surfaces, the Stern layer responses reflect interfacial hydrogen bonding. Our findings thus corroborate that the water bending mode signal is a suitable probe for the structure of interfacial water.

The Bending Mode of Water: A Powerful Probe for Hydrogen Bond Structure of Aqueous Systems

Insights into the microscopic structure and dynamics of the water's hydrogen-bonded network are crucial to understand the role of water in biology, atmospheric and geochemical processes, and chemical reactions in aqueous systems. Vibrational spectroscopy of water has provided many such insights, in particular using the O-H stretch mode. In this Perspective, we summarize our recent studies that have revealed that the H-O-H bending mode can be an equally powerful reporter for the microscopic structure of water and provides more direct access to the hydrogen-bonded network than the conventionally studied O-H stretch mode. We discuss the fundamental vibrational properties of the water bending mode, such as the intermolecular vibrational coupling, and its effects on the spectral lineshapes and vibrational dynamics. Several examples of static and ultrafast bending mode spectroscopy illustrate how the water bending mode provides an excellent window on the microscopic structure of both bulk and interfacial water.

Affinity of Hydrated Protons at Intrinsic Water/Vapor Interface Revealed by Ion-Induced Water Alignment

Protons at the water/vapor interface are relevant for atmospheric and environmental processes, yet characterizing their surface affinity on the quantitative level is still challenging. Here we utilize phase-sensitive sum-frequency vibrational spectroscopy to quantify the surface density of protons (or their hydronium form) at the intrinsic water/vapor interface through inspecting the surface-field-induced alignment of water molecules in the electrical double layer of ions. With hydrogen halides in water, the surface adsorption of protons is found to be independent of specific proton-halide anion interactions and to follow a constant adsorption free energy, ΔG ≈ -3.76 (±0.79) kJ/mol, corresponding to a partitioning coefficient of the surface with respect to bulk water by 3.3∼6.2, for bulk ion concentrations up to 0.3 M. Our spectroscopic study not only is of importance in atmospheric chemistry but also offers a microscopic-level basis to develop advanced quantum-mechanical models for molecular simulations.

Direct Quantification of Water Surface Charge by Phase-Sensitive Second Harmonic Spectroscopy

We developed and verified a phase-sensitive second harmonic generation spectroscopic scheme that allows for direct determination of the absolute surface charge density and surface potential of a water interface without the need for prior interfacial information. The method relies on selective probing of surface-field-induced reorientation order of water molecules in the electrical double layer and is, hence, independent of the interfacial molecular bonding structure. Application of this technique to a mixed surfactant monolayer on water suggests the manifest effect of the chain-chain interactions among the monolayer on adsorption of soluble ionic surfactants. We also deduce the third-order nonlinear susceptibility of bulk water and prove its applicability to analysis of charges of various water interfaces. In addition, we show that Debye-Hückle theory should be avoided in the spectroscopic analysis for its potential significant error, as evidenced experimentally and theoretically.

Hemophagocytic lymphohistiocytosis is a sign of poor outcome in pediatric Epstein-Barr virus-associated post-transplant lymphoproliferative disease after allogeneic hematopoietic stem cell transplantation

EBV-related PTLD developing after HSCT is a potentially life-threatening disease. HLH is uncommon after allogeneic HSCT. Data on outcome of patients with PTLD and concomitant HLH after allogeneic HSCT are limited. In this retrospective study, we collected demographic, clinical, laboratory, and outcome data for 408 patients who underwent allogeneic HSCT from 2006 to 2015. Graft source included CB (n = 135; 33.1%), PBSCs (n = 34; 8.3%), and BM (n = 239; 58.6%). Eight out of 408 patients (2%) developed EBV-PTLD with a median age at HSCT of 5.9 years (range: 2.3-17.3). All eight patients received ATG as part of the conditioning regimen. Graft source was PBSC in three patients (37.5%), BM in four patients (50%), and CB in one patient (12.5%). Donors were matched unrelated in five patients (62.5%) and matched sibling in three patients (37.5%). Seven out of eight patients developed EBV-PTLD within the first 100-day post-HSCT. Lymph node biopsy revealed early lesions in three patients, polymorphic in three patients, and monomorphic PTLD in two patients. Three patients (37.5%) died within 1 month of EBV-PTLD diagnosis. All deceased patients developed HLH manifestations with two of them meeting HLH diagnostic criteria and one having an incomplete workup. PTLD after allogeneic HSCT with manifestations of HLH is associated with high mortality. Early identification and treatment of EBV-PTLD seems imperative to control the disease, especially if signs of HLH are evolving.

A Multicenter Retrospective Analysis Stressing the Importance of Long-Term Follow-Up after Hematopoietic Cell Transplantation for β-Thalassemia

Allogeneic hematopoietic cell transplantation (HCT) is curative in patients with β-thalassemia major. However, most reports on HCT outcomes lack long-term follow-up data with the exception of single-center reports. An international multicenter retrospective data collection and analysis was conducted in 176 β-thalassemia patients who were 1 year or beyond after first HCT to evaluate follow-up methods and outcomes at 7 centers. Median age at HCT was 5.5 years (range, .6 to 18.5), and median follow-up was 7 years (range, 1 to 20). HCT was predominantly from HLA-matched related donors (91%) with bone marrow as stem cell source (91%) and myeloablative conditioning regimens (88%). Late mortality or persistent chronic graft-versus-host disease (GVHD) was rare (<2%). Graft rejection was reported in 23% (24% of these occurred beyond 1 year) post-HCT. Of 119 patients with donor chimerism results available for ≥4 years post-HCT, 50% had >95%, 22% had 50% to 95%, 7% had 20% to 50% and 25 (21%) had <20% donor chimerism. Organ dysfunction was identified in 10% pre-HCT and in 20% post-HCT even without complete clinical details on all patients. Hypogonadism and elevated creatinine for age were most commonly reported and significantly higher in recipients ≥ 7 years at the time of HCT (P = .007) and in those with pre-existing morbidity before HCT (P = .02). Outcomes were unaffected by pre-HCT ferritin or GVHD. Mean z scores for height and weight were low at baseline and remained low post-HCT (79%), confirming that growth impairment from disease lacked recovery post-HCT during this follow-up period. HCT for β-thalassemia has a high rate of cure and low mortality, especially in the young and from HLA-matched related donors. Half of the number of recipients live with mixed chimerism that requires continued follow-up because of a risk of late graft rejection (14%). Organ function after HCT when <7 years of age was generally preserved. Hypogonadism, renal dysfunction, and growth impairment that failed to correct were late complications identified most frequently in older transplant recipients. Systematic follow-up of individual organs such as lung and heart were inadequate but important. These data support the development of simple measures of uniformly tracking long-term HCT outcomes and organ functions in children and adolescents who undergo HCT for thalassemia, allowing for systematic identification and implementation of standardized surveillance strategies and interventions.

The safety of autologous and metabolically fit bone marrow mesenchymal stromal cells in medically refractory Crohn's disease - a phase 1 trial with three doses

BACKGROUND

Mesenchymal stromal cells ability to reset immune functionalities may be useful in Crohn's disease.

AIM

To perform a first-in-human phase 1 safety clinical trial of metabolically fit autologous bone marrow-derived mesenchymal stromal cells in 12 subjects with Crohn's disease utilising three doses.

METHODS

Autologous mesenchymal stromal cells were derived from marrow aspirate and propagated for 2-3 weeks with fibrinogen depleted human platelet lysate and subsequently administered to subjects without interval cryobanking. Twelve subjects received a single mesenchymal stromal cell intravenous infusion of 2, 5 or 10 million cells/kg BW(n = 4/group). Infused mesenchymal stromal cells were analysed for cell surface marker expression, IDO(indoleamine 2,3-dioxygenase) upregulation by IFNγ stimulation, and inhibition of third party peripheral blood mononuclear cell proliferation in vitro. The primary end point measured was safety and tolerability; clinical response was assessed as a secondary endpoint.

RESULTS

All patients tolerated the mesenchymal stromal cell infusion well and no dose limiting toxicity was seen. Seven patients had serious adverse events of which five were hospitalisations for Crohn's disease flare. Two of these serious adverse events were possibly related to the mesenchymal stromal cells infusion. Five subjects showed clinical response 2 weeks after the infusion. Mesenchymal stromal cell phenotype, cytokine responsiveness, and peripheral blood mononuclear cell proliferation blockade were not different among the patients.

CONCLUSION

Single infusion of fresh autologous bone marrow mesenchymal stromal cells propagated ex vivo using human platelet lysate-supplemented media was safe and feasible at intravenous doses of up to 10 million cells/kg BW in patients with Crohn's disease.

Unrelated cord blood transplantation in children with sickle cell disease: review of four-center experience

UCBT was performed in seven children with SCD and stroke (HLA match 4/6 n=5; 5/6 n=2). Four received myeloablative regimens (BU, CY, ATG plus FLU in one patient). One had primary graft failure, three had sustained engraftment, two with grade III-IV GVHD (one died, one developed chronic GVHD), one with stable mixed chimerism. Three patients treated with reduced-intensity regimens (FLU, BU or CY, ATG, TLI) failed to engraft; one engrafted after second UCBT (HU, TT, RXA, ALZ, TBI). Four patients (57%) developed viral infections. Engraftment, GVHD, and infection remain challenges.

Transplantation of unrelated placental blood cells in children with high-risk sickle cell disease

The lack of healthy HLA-identical sibs limits the use of allogeneic hematopoietic cell transplantation in children with high-risk sickle cell disease (SCD). We evaluated unrelated placental blood cell transplantation (UPBCT) after a preparative regimen of busulfan, cyclophosphamide and antithymocyte globulin in three children with SCD who had cerebrovascular accidents (CVAs) and did not have HLA-matched sib donors. The placental blood cell units were matched with the recipients at four of six HLA-A, HLA-B and HLA-DRB1 antigens. Neutrophil levels above 0.5 x 10(9)/l occurred at 23, 38 and 42 days after UPBCT, and platelet levels above 50 x 10(9)/l without transfusions occurred at 62, 81 and 121 days after UPBCT. All patients developed acute graft-versus-host disease (GVHD; two grade II, one grade III), and one developed extensive chronic GVHD. One patient had graft failure and autologous hematopoietic recovery. Two patients have complete donor hematopoietic chimerism without detectable hemoglobin S or symptoms of SCD at 40 and 61 months, respectively, after UPBCT. These observations demonstrate the feasibility of UPBCT in children with SCD. Further studies of UPBCT for SCD are needed but, because of risks of procedure-related morbidity and graft rejection, should be restricted to pediatric patients with high-risk manifestations of SCD.

Haploidentical vs autologous hematopoietic stem cell transplantation in patients with acute leukemia beyond first remission

This is a retrospective comparison of partially mismatched related donor transplantation (PMRDT) and autotransplantation (ABMT) in advanced acute leukemia. Patients underwent T-cell-depleted PMRDT (n=164) or ABMT (n=131) for acute myeloid leukemia (n=130) or acute lymphoblastic leukemia (n=165). Fewer PMRDT patients were in remission (29 vs 85%; P<0.0001). The 5-year cumulative incidence of transplant-related mortality (TRM) was 52% after PMRDT and 16% after ABMT (P<0.0001). The 5-year cumulative incidence of relapse was 32% after PMRDT and 54% after ABMT (P=0.006). The actuarial unadjusted 5-year disease-free survival (DFS) was 16% after PMRDT and 30% after ABMT. In Cox's regression analysis, PMRDT (P<0.0001) and age >15 years (P=0.002) were associated with higher TRM, active disease (P=0.0021), ABMT (P=0.0074) and male sex (P=0.011) with higher relapse, and age >15 years (P=0.0007) and PMRDT (P=0.047) with lower DFS. Amongst second remission patients, TRM was higher after PMRDT (P=0.0003), relapse was higher after ABMT (P=0.034), and 5-year DFS was comparable (32% ABMT and 25% PMRDT). ABMT, if feasible, may be preferable to PMRDT in advanced acute leukemia patients since lower relapse after PMRDT is offset by higher TRM. If an autograft is not feasible because of nonavailability of autologous cells or very advanced disease, PMRDT is a potential alternative.

Should we be performing more combined hematopoietic stem cell plus solid organ transplants?

Both bone marrow and solid organ transplants (SOTs) can be life saving for a wide variety of diseases. We reviewed the literature and summarized the experiences of dual transplants. In total, 37 patients received a SOT for organ failure after a previous hematopoietic stem cell transplant. In all, 12 subjects received SOTs followed by a bone marrow transplant, while three patients received simultaneous SOTs and bone marrow transplants. Of these 52 patients, 37 were alive at the time of the original report at follow-up times ranging from 3 months to 8 years. A special registry for data collection may prove helpful for obtaining long-term follow-up data and providing outcome information that may improve future patient survival.

Allogeneic transplantation from HLA-matched sibling or partially HLA-mismatched related donors for primary refractory acute leukemia

Allogeneic transplantation is successful in a minority of patients with primary refractory acute leukemia (PRAL). An HLA-matched sibling donor (MSD) is available only in 30-40% of the patients, whereas a partially mismatched related donor (PMRD) is available for most. We compared the outcome of 24 MSD (median age 24 years) and 19 PMRD (median age 34 years; P = 0.04) allograft recipients with PRAL. All MSD patients received non-T cell-depleted marrow whereas all PMRD patients received partially T cell-depleted marrow. All evaluable PMRD patients and 90% of the evaluable MSD patients attained CR. Six patients in each group with recurrent/persistent disease died. Ten PMRD (3-year probability 70%) and 14 MSD (3-year probability 63%) patients died of treatment-related causes. At the last follow-up, three PMRD (18-50 months; 3-year probability 14%) and four MSD (20-166 months; 3-year probability 20%) patients were alive and well. We conclude that allogeneic transplantation is a viable therapeutic option for PRAL. PMRD transplantation is a reasonable alternative in patients with no MSD, and results in similar outcome. In terms of identifying a donor and harvesting cells, a PMRD transplant is significantly quicker than an unrelated donor transplant - a point of great practical importance in the setting of failed induction chemotherapy where time is of the essence.

Partially mismatched related donor bone marrow transplantation as salvage for patients with AML who failed autologous stem cell transplant

Treatment options for patients who relapse are limited and the outcome is dismal. Between August 1993 and January 1999, 17 patients, median age 26 (4-44) years, underwent T cell depleted bone marrow transplant from partially mismatched related donors (PMRD), as a salvage for AML relapsing after an autograft. The median time from auto-transplant to relapse was 7 months (1.5-24) and the interval between transplants was 10 months (3-30). All patients had active leukemia at time of transplant. Donors were siblings (n = 8), parents (n = 2), daughters (n = 4) and others (n = 3), and 82% were > or = 2 major HLA antigen mismatched with the recipient. The conditioning therapy included total body irradiation in 14 patients and was busulfan-based in three. Graft-versus-host disease (GVHD) prophylaxis consisted of partial T cell depletion along with post-transplant immunosuppression. Median day to engraftment was 16 days (12-20). Acute GVHD was seen in six patients, and chronic GVHD in four of 13 surviving beyond 100 days. Ten patients died of non-relapse causes, at 1-588 (median 77) days. Two patients relapsed at 3 and 4 months. Five patients (29%) are surviving leukemia-free 42-84 months post transplant (median 68 months). A short interval between transplants was predictive of early relapse but not mortality. Age <18 and <2 organ toxicities were marginally predictive of better survival. We conclude that BMT from PMRD is a reasonable option for patients with refractory AML post autograft.

Epstein-Barr virus-associated B cell lymphoproliferative disorder following mismatched related T cell-depleted bone marrow transplantation

Epstein-Barr virus (EBV) is closely associated with the progressive and often fatal lymphoproliferative disorders (LPD) in post bone marrow transplantation (BMT) and immunocompromised hosts. The incidence increases significantly when alternative donors or manipulation of marrow graft are used. A total of 318 consecutive BMT from partially mismatched related family donors (PMRD) were performed between February 1993 and June 1998. Known risk factors for the development of EBV-LPD were analyzed which included HLA mismatches, T cell depletion, antithymocyte globulin (ATG), and graft-versus-host disease (GVHD). Eighteen patients (5.7%) developed EBV-LPD at a median of 137 days post BMT (range 48-617). The estimated probability of developing EBV-LPD was 0.13 (95% CI 0.07-0.19) at 5 years. The incidence of grade II to IV GVHD was 19.2%, which translated into an increased trend of EBV-LPD. No correlation with other risk factors was observed. Treatment consisted of supportive antiviral agents, tapering of immunosuppressive regimens, donor leukocyte infusions and radiation. Three patients are alive and disease-free at a median follow-up of 69 months (range 36-71). We observed a lower than expected incidence of EBV-LPD despite existing multiple high-risk factors. We believe prevention and early control of GVHD may contribute to this finding.

In vitro generation of Epstein-Barr virus-specific cytotoxic T cells in patients receiving haplo-identical allogeneic stem cell transplantation

Use of a partially mismatched related donor (PMRD) is an option for patients who require allogeneic transplantation but do not have a matched sibling or unrelated donor. Epstein-Barr virus (EBV)-induced lymphoma is a major cause of mortality after PMRD transplantation. In this study, we present a clinical grade culture system for donor-derived EBV-specific cytotoxic T cells (CTLs) that do not recognize haplo-identical recipient cells. The EBV-specific CTLs were tested for cytolytic specificity and other functional properties, including ability to transgress into tissues, propensity for apoptosis, degree of clonality, stability of dominant T-cell clones, and Tc and Th phenotypes. The EBV-specific CTLs were routinely expanded to greater than 80 x 10(6) over a period of 5 weeks, which is sufficient for clinical application. A CD8+ phenotype predominated, and the CTLs were highly specific for donor lymphoblastoid cell lines (LCLs) without killing of recipient targets or K562. Vbeta spectratyping showed an oligoclonal population that was stable on prolonged culture. The EBV-specific CTLs were activated (D-related human leukocyte antigen [HLA-DR+], L-selectin+/-) and of memory phenotype (CD45RO+). Expression of the integrin VLA-4 suggested that these CTLs could adhere to endothelium and migrate into tissues. The Bcl-2 message was upregulated, which may protect the CTLs from the apoptosis. The first demonstration of overexpression of bcl-2 in human memory CTLs. In addition, we show that lymphoblastoid cell lines used to generate CTLs are readily genetically modified with recombinant lentivirus, indicating that genetically engineered antigen presentation is feasible.

Formation of heavy metal species during PVC-containing simulated MSW incineration

The effect of PVC-derived chlorine on heavy metal emissions in MSW incineration was investigated using a tubular furnace and simulated MSW spiked with PVCs and heavy metals (Cd, Cr, Cu, and Zn). The molar ratio of the chlorine content to that of the heavy metal (Cl/M ratio) was varied from 3-200 as one parameter. The results indicated that the major species found in the fly ash were chlorides of alkaline and alkali-earth metals, whereas those identified in the bottom ash were MgSiO3, SiO2 and some complex aluminates and silicates. The emission of heavy metals and/or their compounds, with extreme and medium volatility, tended to be enhanced within the lower Cl/M range, whereas those with a refractory volatility were likely to be affected within the higher Cl/M range. However, those with an extremely refractory volatility were less affected by an increase of the Cl/M ratio. The variation of speciation and partitioning in MSW combustion as affected by the Cl/M ratio are discussed.

The effects of FeCl3 on the distribution of the heavy metals Cd, Cu, Cr, and Zn in a simulated multimetal incineration system

Recognizing that waste-derived chlorine can enhance heavy metal emissions by forming volatile metallic chlorides during municipal solid waste (MSW) combustion, and that in Taiwan, FeCl3-containing sewage sludge may either be landfilled or coincinerated with other MSW, this study thus investigated the effects of FeCl3 on the speciation and partitioning of heavy metals in a multimetal incineration system by using a tubular furnace and FeCl3-spiked simulated wastes. The molar ratio of chlorine content to heavy metal content (referred to as the Cl/ M ratio), ranging from 3 to 200, was used as a parameter to evaluate the effects of chlorine on the movement of heavy metals between the incinerator discharges. Results indicate that speciation and partitioning were related to the affinity between the chlorine and the heavy metals and between chlorine and hydrogen in the combustion system. The effectiveness of increasing the Cl/M ratio to the formation potential of metallic chlorides and on the shift of heavy metals from the bottom ash to the fly ash and/or the flue gases was found to have in increasing order as follows: Zn>Cu>Cr, a phenomenon basically reflecting the volatility of the heavy metals and their chlorides formed during combustion.

Allogeneic bone marrow transplantation from partially mismatched related donors as therapy for primary induction failure acute myeloid leukemia

The outcome of acute myeloid leukemia patients with primary refractoriness to conventional chemotherapy is extremely poor. Allogeneic bone marrow transplants with matched sibling or matched unrelated donors provide 10-20% disease-free survival in this setting. We analyzed our transplant experience using readily available partially mismatched related donor (PMRD) in patients with primary induction failure (PIF) AML. Between March 1994 and December 1998, 13 patients with PIF AML were transplanted from 0-3 HLA antigen mismatched donors. All 12 evaluable patients engrafted at a median of day +16. Ten (77%) patients survived at least 100 days after transplant. Acute GVHD (grade II) was observed in one of 12 patients. Chronic GVHD was seen in one of 10 patients surviving beyond day 100. The major cause of failure was relapse of disease in six occurring 3-12 months after PMRD BMT. Three patients are alive without disease 14, 36 and 45 months post BMT with Karnofsky scores of 100%. The actuarial 3-year probabilities of relapse and disease-free survival were 0.54 and 0.19, respectively. We concluded that a PMRD graft is a viable option, comparable to the use of matched related or unrelated donors, in patients with PIF AML in whom time is of the essence.

Stabilization of heavy metals in sewage sludge composting process

This study investigated the stabilization of heavy metals in a sewage sludge composting process using kaoline addition. The results indicate that the temperature increased rapidly to the thermophilic phase (>55 degrees C) at day 1. The additives enhanced the rate of biodegradation and microbial activity during the co-composting process. The changes in pH (ranging from 8 to 8.5) and electrical conductivity (EC) (< or =3 mS/cm) were in compliance with the best conditions during the co-composting process. The C/N ratio was determined in each co-compost sample as an indicator of the co-compost maturity. From the end product of the co-compost experiment, changes in the ratios indicate that the additives promote the co-compost maturation rate. Based on the physicochemical characteristics of the co-compost, the potential use for sewage sludge resource recovery as manure is suggested. The total concentrations of Pb, Cd, Cr, Cu, and Zn in the co-compost product were far below the limit values for agricultural use. The leachability of Pb, Cu, and Cr decreased with increasing co-composting time. That is, the kaoline additive has an inhibitory capacity for leaching heavy metals. The Cd concentrations in the sludge compost were below the detection limits. Because the total concentration of Zn was high in the sludge compost and most soluble Zn was leachable, the leachability of Zn ranged from 25% to 29%. As a result of the physicochemical characteristics and heavy metal stabilization, the selected additive was shown to improve the sewage sludge compost quality and provide information for agricultural applications.

Non-myeloablative allogeneic transplantation ('microallograft') for refractory myeloma after two preceding autografts: feasibility and efficacy in a patient with active aspergillosis

A 59-year-old man with a 4-year history of light chain myeloma relapsing after two preceding autografts and salvage therapy with thalidomide underwent a peripheral blood stem cell (PBSC) transplant from his HLA-identical sister after conditioning with 100 mg/m2 melphalan. Graft-versus-host disease (GVHD) prophylaxis comprised cyclosporine. Despite pulmonary infiltrates and sinusitis at the time of the allograft, it was decided to proceed with the transplant because the myeloma was refractory and rapidly progressive. Sputum cultures obtained 2 days before the allograft grew Aspergillus fumigatus 2 days post transplant. A fumigatus grew repeatedly on specimens obtained post transplant. Prompt hematologic recovery was seen with full donor-type chimerism. The fungal infection subsided gradually on a combination of amphotericin B lipid complex and itraconazole. A second aliquot of donor PBSC was infused electively on day +42 to induce graft-versus-myeloma. Complete remission of the myeloma was achieved by 75 days post transplant. No acute GVHD was seen. No chronic GVHD was seen at 16 weeks when he received the third PBSC infusion. He is currently alive and well in remission 9 months post transplant. This case demonstrates the safety and potential usefulness of allogeneic PBSC transplantation with reduced-intensity conditioning in patients with markedly compromised performance status.

Evaluation of the half-life of intravenous human cytomegalovirus immune globulin in patients receiving partially mismatched related donor bone marrow transplantation

STUDY OBJECTIVE

To evaluate the pharmacokinetics and use of intravenous human cytomegalovirus immune globulin (CytoGam) in allogeneic bone marrow transplantation (BMT).

DESIGN

Prospective, nonrandomized, nonblinded, single-center study.

SETTING

University teaching hospital.

PATIENTS

Five consecutive patients with hematologic malignancies receiving partially mismatched related donor BMT with a uniform conditioning regimen including total body irradiation and chemotherapy.

INTERVENTION

Serum immunoglobulin and cytomegalovirus (CMV) titers were measured before and 24 hours after the first CytoGam infusion on day -6 during the conditioning regimen.

MEASUREMENTS AND MAIN RESULTS

These levels were measured every 5 days, and a second dose was administered when the CMV titer returned to 25-50% of the 24-hour level. The half-life of CytoGam was approximately 7 days.

CONCLUSION

We believe this is the first report of CytoGam's half-life in allogeneic BMT. The information may prove vital in a future study in which the agent's potential beneficial effects can be maximized.

Partially mismatched related-donor bone marrow transplantation for pediatric patients with acute leukemia: younger donors and absence of peripheral blasts improve outcome

PURPOSE

To extend access to bone marrow transplantation (BMT), we used partially mismatched related donors (PMRD) for pediatric patients with acute leukemia. In this report we sought to determine pretransplantation factors that might predict outcome.

PATIENTS AND METHODS

Of 67 such patients, 43 had acute lymphocytic leukemia and 24 had acute myelogenous leukemia. At the time of transplantation, 41 patients were in relapse. Donors included 40 parents, 24 siblings, and three cousins. HLA disparity of two to three major antigens was detected in two thirds of the donor-recipient pairs. Conditioning therapy, including total-body irradiation and chemotherapy followed by graft-versus-host disease (GvHD) prophylaxis with partial T-cell depletion of the graft using T10B9 or OKT3, was combined with posttransplantation immunosuppression.

RESULTS

Estimated probability (EP) of engraftment was 0.96 and was not affected by donor-antigen mismatch (AgMM; P =.732). EP of grades 2 to 4 acute GvHD was 0.24 and was not affected by recipient AgMM (P =.796). EP of disease-free survival was 0.26 at 3 years but improved to 0.45 when donors were younger than 30 years (P<.001). EP of relapse at 3 years was 0.41 and reduced with younger donors' age. For patients who were in relapse at the time of transplantation, absence of blasts was associated with a lower relapse rate (0.46 v. 0.84; P =. 083), similar to that of patients in remission.

CONCLUSION

PMRD-BMT in pediatric leukemia resulted in high engraftment and low GvHD rates. To improve outcomes, younger donors should be sought, and clinicians should attempt to reduce peripheral blasts in patients who are in relapse.

Effects of chlorides on emissions of toxic compounds in waste incineration: study on partitioning characteristics of heavy metal

Chlorides derived from plastics and food residue content in MSW will affect the formation and partitioning of metal chlorides in the incineration discharges. Our study investigated the effects of waste-derived chlorides on the partitioning of heavy metals in a single-metal combustion system. The results indicate that the heavy metal partitioning behaviors are mainly affected by the presence of chloride, alkaline metals (i.e., Na, K) and moisture in the wastes. The configuration of the metal partitioning is determined by the availability of chlorine, hydrogen, and alkaline metals, or the extent to which the elements may divide from their compounds at a given combustion temperature. The effects of chlorides, including PVC, C2Cl4, FeCl3, NaCl and KCl, were also discussed.

Late onset Epstein-Barr virus-associated lymphoproliferative disease after allogeneic bone marrow transplant presenting as breast masses

We report a patient who developed breast masses 17 months after a T cell-depleted partially mismatched related donor (PMRD) bone marrow transplant (BMT) for chronic myeloid leukemia. The patient had severe chronic graft-versus-host disease (GVHD) and the masses were due to Epstein-Barr virus (EBV) lymphoproliferative disease (LPD). The patient expired from fungal pneumonia after chemotherapy for the EBV-LPD.

Outcome of second bone marrow transplantation following a uniform conditioning regimen as therapy for malignant relapse

Twenty-three second bone marrow transplants (BMT) were performed between October 1987 and January 1994 for patients with malignant relapse following initial BMT. For first BMT, twenty-one of 23 (91%) were conditioned with cyclophosphamide plus total body irradiation. For second BMT, a uniform conditioning regimen consisting of busulfan and cyclophosphamide was used. Eleven patients had chronic myelogenous leukemia, seven acute leukemia, four lymphoma, and one myelodysplastic syndrome. Median patient age at second BMT was 32 years, the median time between first BMT and relapse was 22 months, and the median time to second BMT after relapse was 5 months. The second BMT marrow source included: autologous marrow (1), unrelated donors (4), new matched sibling donors (5) and same matched sibling donors as the first BMT (13). The Kaplan-Meier disease-free survival and survival rates at 3 years were 38 and 43%, respectively (median follow-up of survivors was 45 and 48 months, respectively), and five patients survive disease-free at 4-6 years. Nine of the 13 deaths occurred within 100 days after second BMT; eight had relapsed within 1 year of the first BMT. We conclude that: (1) second BMT can offer durable long-term survival in certain patients, especially those who relapse late after first transplant; (2) busulfan and cyclophosphamide is a suitable conditioning regimen for second BMT.